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To make sound clinical decisions when treating patients with knee disorders, it is necessary to understand the various pathologies, surgical procedures, and associated precautions and to identify presenting structural and functional impairments, activity limitations (functional limitations), and possible participation restrictions (disabilities). In this section, common pathologies and surgical procedures are presented and related to corresponding preferred practice patterns (groupings of impairments) described in the Guide to Physical Therapist Practice3 (Table 21.1). Conservative and postoperative management of these conditions is described in this section.
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+++
Joint Hypomobility: Nonoperative Management
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Common Joint Pathologies and Associated Impairments
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OA and rheumatoid arthritis (RA), as well as acute joint trauma, can affect the knee articulations. In addition, decreased flexibility and adhesions develop in the joints and surrounding tissues any time the knee joint is immobilized for a period of time such as following an injury, surgery, or fracture in the related bones. Reflex inhibition and resulting weakness of the quadriceps femoris muscle occurs because of joint distention.272 The etiology of arthritic and joint symptoms and general management guidelines are described in Chapter 11; this section applies that information to management of the knee joint.
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Osteoarthritis (Degenerative Joint Disease)
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OA, often referred to as degenerative joint disease (DJD), is the most common disease affecting weight-bearing joints. Articular cartilage destruction typically is more apparent on the medial than the lateral aspect of the knee (Fig. 21.5).
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++
One-third of individuals older than age 65 have radiographic evidence of OA.16 Pain, muscle weakness, medial joint laxity, and limitation of joint motion affect function and lead to disability. Deformity such as genu varum commonly develops in the knees. Knee instability (the sensation of knee buckling or shifting) is also frequently reported by individuals with knee OA and significantly contributes to impaired physical function.78
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FOCUS ON EVIDENCE
An investigation of 52 patients with medial knee OA by Schmitt and associates246 found that self-reported knee instability contributed to limited function during daily living. However, the findings of the study showed no direct relationship between the severity of reported knee instability and the amount of medial joint laxity, varus alignment of the knee, or quadriceps muscle strength (maximum voluntary isometric contraction.
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Factors such as excess weight, joint trauma, developmental deformities, weakness of the quadriceps muscle, and abnormal tibial rotation are identified as risk factors for developing OA of the knee.16
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Posttraumatic arthritis of the knee occurs in response to any injury that affects the joint structures, particularly following acute ligament and meniscal tears. Joint swelling (effusion) may be immediate, indicating bleeding within the joint, or progressive (more than 4 hours to develop), indicating serous effusion. Acute symptoms include pain, limited motion, and muscle guarding. Trauma, including repetitive microtrauma, is a common cause of degenerative changes in the knee joint.
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Early-stage rheumatoid arthritis (RA) usually manifests first in the hands and feet. With progression of the disease process, the knees also may become involved. The joints become warm and swollen, and limited motion develops. In addition, a genu valgum deformity commonly develops during the advanced stages of this disease.
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Postimmobilization Hypomobility
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When the knee has been immobilized for several weeks or longer, such as during healing of a fracture or after surgery, the capsule, muscles, and soft tissue develop contractures, and motion becomes restricted. Adhesions may restrict caudal gliding of the patella, which limits knee flexion, and may cause pain as the patella is compressed against the femur. An extensor lag may occur with active knee extension if the patella does not glide proximally when the quadriceps muscle contracts.274 This usually occurs after operative repairs of some knee ligaments, when the knee is immobilized in flexion for a prolonged period.
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Common Structural and Functional Impairments
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With joint involvement, the pattern of restriction at the knee is usually more loss of flexion than extension.
When there is effusion (swelling within the joint), the joint assumes a position near 25° of flexion, the position at which there is the greatest capsular distensibility. Little motion is possible because of the swelling.
Symptoms of joint involvement, such as distention, stiffness, pain, and reflex quadriceps inhibition, may cause extensor (quadriceps) lag in which the active range of knee extension is less than the passive range available.274
Impaired balance responses also have been reported in patients with arthritis.295
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Common Activity Limitations and Participation Restrictions (Functional Limitations and Disabilities)
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With acute symptoms and in advanced stages of degeneration, there is pain during motion, weight bearing, and gait that may interfere with work or routine household and community activities.
There is limitation of, or difficulty controlling, weight-bearing activities that involve knee flexion, such as sitting down and rising from a chair or a commode, descending or ascending stairs, stooping, or squatting.75
With end-stage arthritis, physical activity is markedly curtailed with less participation in leisure activities (e.g., walking, gardening, swimming, athletic activities) and household activities (e.g., dusting, washing floors, cleaning, shopping).285
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Joint Hypomobility: Management—Protection Phase
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See Chapter 11 for general guidelines for the management of acute joint lesions and specific guidelines for OA and RA.
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Control Pain and Protect the Joint
++
Patient education. It is important to teach the patient methods to protect the joint including bed positioning, use of splints in order to avoid deforming contractures, range-of-motion (ROM) and muscle-setting exercises to maintain mobility and promote blood flow, and safe functional activities that reduce stresses on the knee.
++
Functional adaptations. Instruct the patient to minimize stair-climbing, use elevated seats on commodes, and avoid deep-seated or low chairs in order to minimize stressful knee flexion ranges while bearing weight. If necessary during an acute flare of arthritis, have the patient use crutches, canes, or a walker to distribute forces through the upper extremities while walking.
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Maintain Soft Tissue and Joint Mobility
++
Passive, active-assistive, or active ROM. Use ROM techniques within the limits of pain and available motion. The patient may be able to perform active ROM in the gravity-eliminated, side-lying position, or self-assisted ROM.
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Grade I or II joint distraction and anterior/posterior glides. Apply gentle joint techniques, if tolerated, with the joint in or near resting position (25° flexion). These techniques are used to inhibit pain as well as maintain joint mobility. Stretching is contraindicated at this stage.
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Maintain Muscle Function and Prevent Patellar Adhesions
++
Setting exercises. Perform pain-free quadriceps ("quad sets") and hamstring muscle-setting exercises with the knee in various pain-free positions, quad sets with leg raises, and submaximal closed-chain muscle setting exercises. Muscle-setting exercises are described in detail in the last section of this chapter. Quad sets may help maintain mobility of the patella when the tibiofemoral joint is immobilized and therefore are routinely taught following surgery or when the joint is immobilized.
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Joint Hypomobility: Management—Controlled Motion and Return to Function Phases
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As joint effusion decreases and joint tissues are able to tolerate increased stresses, the goals of treatment change to deal with the impairments that interfere with functional activities. The patient is progressed through controlled motion exercises and activities that focus on safely returning to desired functional outcomes.
++
Inform the patient about his or her condition, what to expect regarding recovery, and how to protect the joints.
Teach the patient safe exercises to do at home, how to progress them, and how to modify them if symptoms are exacerbated by the disease or from overuse. Exercises that include specifically designed strengthening, stretching, ROM, and use of a stationary bicycle have been shown to improve functional outcomes in patients with OA in a home exercise program.58 It is important to emphasize that maintaining strength in the supporting muscles helps protect and stabilize the joint and that balance exercises help reduce the incidence of falls.
Instruct the patient to perform active ROM and muscle-setting techniques frequently during the day, especially prior to bearing weight, in order to reduce the painful symptoms that occur with initial weight bearing.75
The patient with OA or RA should be cautioned to alternate activity with rest.
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FOCUS ON EVIDENCE
In a randomized, controlled study58 of 134 patients with OA of the knees, a clinic treatment group (n=66) underwent treatment that consisted of supervised exercise, manual therapy, and home exercises for 4 weeks. A home exercise group (n=68) performed home exercises only (instructions and a follow-up examination were provided for the same exercises as the clinic treatment group). Outcomes that were measured consisted of the distance walked in 6 minutes and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Both groups improved in the outcome measures at 4 weeks; the clinic treatment group improved 52% on the WOMAC, whereas the home exercise group improved 26%. Both groups improved 10% on the 6-minute walk distances. At 1 year, there was no difference between the groups, and both groups demonstrated improvement over baseline measurements. However, it was noted that the clinic treatment group was less likely to be taking medication for the arthritis and was more satisfied with the outcome of their rehabilitation. The lack of long-term maintenance highlights the importance of patient education and adherence to a prescriptive long-term home exercise program.
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Decrease Pain from Mechanical Stress
++
Continue use of assistive devices for ambulation, if necessary. The patient may progress to using less assistance or may ambulate for periods without assistance. Continue use of elevated seats on commodes and chairs, if needed, to reduce the mechanical stresses imposed when attempting to stand.75
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Increase Joint Play and Range of Motion
++
PRECAUTION: Do not increase ROM unless the patient has sufficient strength to control the motion already available. A mobile weight-bearing joint with inadequate muscle control causes impaired stability and makes lower extremity weight-bearing function difficult.
++
Joint mobilization. When there is loss of joint play and decreased mobility, joint mobilization techniques should be used. Apply grade III or IV sustained or oscillatory techniques to the tibiofemoral and patellofemoral articulations with the joint positioned at the end of its available range before applying the mobilization technique. (See Figures 5.49 through 5.54 and their descriptions in Chapter 5.) As ROM increases, it is important to emphasize the rotational accessory motions that accompany flexion and extension.129
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To increase flexion, position the tibia in medial rotation and apply the posterior glide against the anterior aspect of the medial tibial plateau.
To increase extension, position the tibia in lateral rotation and apply the anterior glide against the posterior aspect of the lateral tibial plateau.
Medial and lateral gliding of the tibia on the femur may also be done to regain mobility for flexion and extension.
++
Stretching techniques. Passive and PNF stretching techniques are used to increase extensibility of the muscles and extracapsular noncontractile soft tissues that restrict knee motion. Specific techniques are described in the last section of this chapter.
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PRECAUTIONS: Techniques that force the knee into flexion by using the tibia as a lever or by using strong quadriceps contractions (during a hold-relax maneuver) may exacerbate joint symptoms.
++
Incorporate the following to minimize joint trauma from stretching.
++
Mobilize the patellofemoral and tibiofemoral joints before stretching in order to improve gliding of the joint surfaces during the stretch maneuvers.
Apply soft tissue or friction massage to loosen adhesions or contractures prior to stretching. Include deep massage around the border of the patella.
Modify the intensity of contraction when applying PNF stretching techniques to range-limiting muscles in order to decrease the effects of joint compression. If the hold-relax technique aggravates anterior knee pain when attempting to increase knee flexion, use the agonist contraction technique to the hamstring muscles to minimize compression from a strong quadriceps muscle contraction.
Use low-intensity, long-duration stretches within the patient's tolerance.
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Mobilization with movement. Mobilization with movement (MWM) may be applied to increase ROM and/or decrease the pain associated with movement by improving joint tracking. Mulligan190 states that MWM is more effective with loss of flexion than extension. The principles of MWM are described in Chapter 5.
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MWM: Lateral or Medial Glides
++
Patient position and procedure: Supine for extension or prone for flexion. Apply a pain-free medial or lateral glide to the tibial plateau manually or through the use of a mobilization belt. The direction of glide is often in the direction of the pain (i.e., lateral knee pain responds best to a lateral glide of the tibia and medial knee pain to a medial glide).190
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While sustaining the mobilization, ask the patient to move to the end of the available pain-free range of flexion or extension.
Add pain-free overpressure to achieve the benefit of end-range loading.
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MWM: Internal Tibial Rotation for Flexion—Manual Technique
++
Patient position and procedure: Supine with the knee flexed to the end of its available pain-free range. Apply internal rotation mobilization to the tibia with manual pressure from one hand on the anteromedial tibial plateau simultaneously with pressure from the other hand on the posterolateral tibial plateau, posterior to the fibular head.
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MWM: Internal Rotation for Flexion—Self-Treatment
++
Patient position and procedure: Standing with the foot of the involved leg on a chair and knee flexed. Position the foot such that the tibia is internally rotated. Have the patient apply internal rotation pressure against the anteromedial and posterolateral tibial plateaus and shift the weight forward to flex the knee to the end of the available pain-free range (Fig. 21.7).
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Improve Muscle Performance in Supporting Muscles
++
Exercises identified in this section are described in detail in the last section of this chapter.
++
Progressive strengthening. Begin with multiple-angle isometrics to both knee flexors and extensors and active ROM exercises in open- and closed-chain positions using a moderate progression of repetitions and resistance in arcs of pain-free motion. Exercise intensity should be within the tolerance of the joint and not exacerbate symptoms.
++
When performing open-chain exercises, patients experience less pain with faster speeds and lighter resistance than when doing the exercises slowly with heavy resistance.
Resistance through the midrange (45° to 90°) tends to exacerbate patellofemoral pain because of the compressive forces on the patella. Apply resistance in arcs of motion that are pain-free on either side of the symptomatic range. This could be done using manual or mechanical resistance in the pain-free ranges.
Strengthen both hip and ankle musculature using open-and closed-chain exercises in order to balance forces throughout the lower extremities and progress the patient toward functional independence. (See Chapters 20 and 22 for hip and ankle exercises.)
++
Muscular endurance training. Increase repetitions at each resistance level before increasing resistance.
++
Functional training. Climbing steps, sitting down and rising up from chairs and commodes, and using safe body mechanics to lift objects from the floor are often compromised in individuals with knee arthritis. It is imperative to strengthen the knee musculature using modifications of functional activities, progressing the difficulty as strength improves.
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Step-up and step-down exercises (forward, backward, lateral). Begin with a low step height, and progress to the step height the patient requires for home and community mobility. Progress to functional activities, such as climbing stairs or ladders, depending on the desired outcomes.
Wall slides and minisquats to 90°, if tolerated. Stay within a range that does not exacerbate symptoms or cause crepitation. Practice sitting down and sit-to-stand with arm assistance to and from various chair heights. Determine if chair adaptation is needed for safe function. Correct lower extremity alignment and posterior weight shift are imperative to activate and strengthen the gluteus maximus for total lower extremity control.
Partial lunges. This activity is progressed to include lunging to pick up small objects from the floor. Lunges are an effective way to teach body mechanics for an individual with unilateral knee impairment. Concentrate on trunk control during the motion. Have the patient activate the lumbopelvic musculature to stabilize the pelvis during the lunge activity.
Balance activities. Balance activities are initiated at the level the patient can control. Detailed suggestions are outlined in Chapters 8 and 23.
Ambulation. Decrease use of assistive devices as quadriceps strength improves to a manual muscle test level of 4/5 and as gait is normalized and symmetrical. Practice walking on a variety of terrains and up and down ramps, and reverse directions, first with assistance and then independently.
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Improve Cardiopulmonary Endurance
++
Select and adapt activities to minimize irritating stresses on the knee.
++
Swimming, water aerobics, and aquatic exercises provide an environment for improving muscular and cardiopulmonary function with minimal joint trauma.
Bicycling is a low-impact form of exercise. Adjust the seat height so the knee goes into complete extension (but not hyperextension) when the pedal is down. On a stationary bike, use low resistance.
High impact activities—with caution. For some patients, progression to running or jumping rope and other high-impact, faster-paced, or more intense activities can be undertaken so long as the joint remains asymptomatic. If joint deformity is present and proper biomechanics cannot be restored, the patient probably cannot progress to these activities.
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Outcomes
Two systematic reviews of studies designed to examine evidence of the effects of exercise in the management of hip and knee OA describe support for aerobic exercise and strengthening exercises to reduce pain and disability.239,240 The consensus of expert opinion cited by Roddy239 is that: (1) there are few contraindications; and (2) exercise is relatively safe in patients with OA, but it should be individualized and patient-centered with consideration for age, comorbidity, and general mobility. Similarly the Cochrane Database of Systematic Reviews,81 the Philadelphia Panel Evidence-Based Clinical Practice Guidelines,223 and more recently a summary of systematic reviews of studies on physical therapy interventions for patients with knee OA123 indicated that there is evidence to support strengthening, stretching, and functional exercises as interventions for the management of knee pain as the result of OA and to improve physical function.
In another study that followed 285 patients with knee OA for 3 years, investigators found that factors that protected the individuals from poor functional outcomes included strength and activity level, as well as factors such as mental health, self-efficacy, and social support.255
An outcome review57 summarized that moderate- or high-intensity exercises for patients with RA have minimal effect on the disease activity but that there is insufficient radiological evidence on the effect on large joints. The review also indicated that long-term moderate- or high-intensity exercises that are individualized to protect radiologically damaged joints improve aerobic capacity, muscle strength, functional ability, and psychological well-being of patients with RA. A 24-month follow-up study by the same researchers revealed a better attainment of muscle strength in participants who continued with the exercise program than those who did not.56
Finally, a recent systematic review by the Osteoarthritis Research Society International recommended a referral to a physical therapy as a nonpharmacological intervention to improve functional capacity of patients with symptomatic OA underscoring the important role of physical therapy for regaining function.313
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Joint Surgery and Postoperative Management
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A range of surgical options for management of arthritis of the knee is available when joint pain and synovitis cannot be controlled with conservative therapy and appropriate medical management or when destruction of articular surfaces, deformity, or restriction of motion have progressed to the point that functional abilities are significantly impaired.
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The surgical procedure selected depends on the patient's signs and symptoms, activity level and age, type of disease, severity of articular damage or joint deformity, and involvement of other joints. Arthroscopic débridement and lavage are used to remove loose bodies that may be causing swelling and intermittent locking of the knee.17,251 A number of procedures to repair damaged articular cartilage have been developed. Abrasion arthroplasty, a procedure designed to smooth worn articular surfaces and stimulate growth of replacement cartilage has met with only limited success.17,251 More recently developed procedures used to repair small, localized articular cartilage defects of the knee, such as microfracture,92,253 osteochondral autograft transplantation (mosaicplasty),12,103,137 and autologous chondrocyte implantation,45,93,298 appear to hold promise.
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Synovectomy was the procedure of choice in the past for a young patient with unremitting joint effusion, synovial proliferation, and/or pain as the result of RA or juvenile RA (JRA) but with minimal destruction of articular surfaces.35,218,251 However, it is now used infrequently. Osteotomy of the distal femur or proximal tibia (an extraarticular procedure) redistributes weight-bearing forces between the tibia and femur in an attempt to reduce joint pain during weight-bearing activities and delay the need for arthroplasty of the knee.17,35,251 In the past, high tibial osteotomy was considered a surgical option for the active patient younger than age 50 to 55 years without active systemic disease and significant limitation of motion or joint deformity. However, because arthroplasty is now performed in younger patients than was the case a decade or two ago, osteotomy is an infrequently selected surgical option.39
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When erosion of articular surfaces becomes severe and pain is unremitting, total knee arthroplasty (total knee replacement) is the surgical procedure of choice to reduce pain, correct deformity, and improve functional movement.119,160,249 Only in highly selective situations is arthrodesis (fusion) of the knee used as a salvage procedure to provide a patient with a stable and pain-free knee.
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Regardless of the type of surgery selected, the goals of surgery and postoperative management are to: (1) reduce pain; (2) correct deformity or instability; and (3) restore lower extremity function. Carefully progressed postoperative rehabilitation is essential for optimal functional outcomes.
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Repair of Articular Cartilage Defects
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Injuries of the ligaments or menisci of the knee and acute or chronic patellofemoral dysfunction often are associated with damage to an articular surface of the knee. Surgical management of chondral defects has proved challenging because of the limited capacity of articular cartilage to heal.45,144 However, several surgical procedures introduced during the 1990s are available for repairing small lesions in the symptomatic knee when nonoperative management or arthroscopic débridement and lavage have been unsuccessful.
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Procedures include microfracture,92,144,253,275 osteochondral autograft transplantation/mosaicplasty,12,18,103,137 and autologous chondrocyte implantation.93,144,298 These procedures are designed to stimulate growth of hyaline cartilage for repair of focal defects of articular cartilage and for preventing progressive deterioration of joint cartilage leading to osteoarthritis.45,144
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Descriptions of procedures specific to the knee are presented in this section. Regardless of the cartilage procedure selected, each requires the patient's ability and willingness to adhere to a lengthy rehabilitation process.
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Indications for Surgery
++
The primary indication for repair of an articular cartilage defect is a symptomatic knee caused by a small to relatively large focal lesion of the tibiofemoral or patellofemoral joint. Sites typically involved are the weight-bearing portions of the medial or lateral femoral condyles, the trochlear groove, and the articulating facets of the patella.
++
Selection criteria when choosing the procedure include the size of the chondral lesion (in general, defects greater than 1 to 2 cm2 but no more than 4 cm2 are considered suitable for repair), the depth of the lesion, the location of the lesion, the elapsed time since the occurrence of the defect, and the patient's age and intended activity level. Most patients who undergo articular cartilage repair are young and active.45,144
++
CLINICAL TIP
A system for classification of cartilage lesions developed by the International Cartilage Repair Society is based on a five-point grading scale. Lesions range from grade 0 (normal cartilage without notable defects) to grade 4 (severely abnormal, full-thickness osteochondral defects).31
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Microfracture. Microfracture is indicated for repair of very small defects, usually of the medial or lateral femoral condyle or the posterior aspect of the patella. The procedure is performed arthroscopically and involves the use of a nonmotorized awl to systematically penetrate the subchondral bone and expose the bone marrow. The procedure is designed to stimulate a marrow-based repair response leading to local ingrowth of cartilaginous repair tissue (fibrocartilage) to repair the lesion.45,92,144,253,275
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Osteochondral autograft transplantation/mosaicplasty. For focal lesions involving chondral or subchondral tissue of the weight-bearing surfaces of the knee, osteochondral graft transplantation may be selected. It is an arthroscopic or mini open procedure involving transplantation of intact articular cartilage along with some underlying bone, resulting in a bone-to-bone graft.12,18,103,137 Rather than using a single piece of tissue and creating a similar size osteochondral defect at the donor site, mosaicplasty is used in which multiple, small-diameter osteochondral plugs are harvested and press-fit into the chondral defect.12,18,103,137
++
Donor sites typically are nonweight-bearing, nonarticulating portions of the supracondylar ridge of the lateral femoral articulating surfaces or elsewhere in the knee.12
++
Autologous chondrocyte implantation. This procedure, also referred to as chondrocyte transplantation, is used for full-thickness chondral and osteochondral defects (2 to 4 cm2) of the femoral condyles or patella.45,93,298 The procedure occurs in two stages. First, healthy articular cartilage is harvested arthroscopically from the patient. Then chondrocytes are extracted from the articular cartilage, cultured for several weeks, and processed in a laboratory to increase the volume of healthy tissue. The second phase is the implantation phase, which currently requires an arthrotomy (open procedure). After the chondral defect sites have been débrided, they are covered with a periosteal patch, typically harvested from the proximal medial tibia and secured with fibrin glue. Then millions of autologous chondrocytes are injected under the patch and into the articular defect.
++
Patient positioning during the first 4 hours after surgery is critical. Patients are positioned so the effect of gravity distributes the chondrocytes evenly along the base of the defect.232 For example, after a patellofemoral repair, the patient is placed in the prone position.
++
Maturation of the implanted chondrocytes is a lengthy process. It may take as long 6 months for the graft site to become firm and as long as 9 months for the graft to become as durable as the healthy tissue surrounding the graft.93
++
Osteochondral allograft transplantation. For defects larger than 4 cm2, the only option for repair—although used infrequently—is an osteochondral allograft of intact articular cartilage from a cadaveric donor. However, only fresh, intact grafts, which are in limited supply and can be stored only a few days, can be used. A frozen allograft cannot be used because freezing the graft material kills the articular chondrocytes, leading to graft failure.45,144
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Other procedures. If coexisting ligament or meniscus pathology or tibiofemoral or patellofemoral malalignment are identified prior to or concomitant with surgical repair, reconstruction or realignment must be carried out for the articular cartilage repair to be successful. The most common procedures are ACL reconstruction and meniscus repair for tibiofemoral articular defects and lateral retinacular release for patellar defects.12,93
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BOX 21.2 Special Considerations and Precautions for Rehabilitation after Articular Cartilage Repair*
The larger the lesion, the slower/more cautious the progression of rehabilitation.
Early but controlled ROM is advocated to facilitate the healing process and begins immediately or within a day or two after surgery (CPM, passive or assisted exercise).
Controlled (protected) weight bearing initiated as early as possible is beneficial to the healing process, but adherence to weight-bearing restrictions is critical.
Duration and degree of weight-bearing restrictions vary with the size of the defect and type and location of the repair.*
Longer period of protected weight bearing for osteochondral transplantation/mosaicplasty and autologous chondrocyte implantation than after microfracture
Longer period of protected weight bearing for a femoral condyle repair (up to 8 to 12 weeks) than for a patellar defect (up to 4 weeks)
Full weight bearing is delayed for as long as 8 to 12 weeks
Protective bracing may be used postoperatively.
Typically locked in extension, except during exercise
Worn during weight-bearing activities 4 to 6 weeks
Worn during sleep for as many as 4 weeks
An unloading brace may be used after repair of a femoral condyle defect to shift the weight away from the repair during the period of protected weight bearing
Return to functional activity.148
Generally, low-impact sports, such as swimming, skating, rollerblading, and cycling, are permitted at about 6 months
High-impact sports, such as jogging, running, and aerobics are permitted at:
Higher-impact sports, such as tennis, basketball, football, and baseball, are permitted at 12–18 months.
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Postoperative Management
++
A cautiously progressed and closely monitored rehabilitation program after articular cartilage repair procedures is critical for a successful outcome. The components and progression of a rehabilitation program, including exercise, ambulation, and functional activities, must be graded to protect the repair or graft and prevent further articular damage while applying controlled stresses to stimulate the healing process.
++
The progression of postoperative exercises and functional activities after microfracture, osteochondral autologous transplantation, and autologous chondrocyte implantation has many common elements, yet they vary to some degree. Detailed postoperative protocols, as well as comprehensive clinical practice guideline for each of these procedures, have been published in the literature.12,93,137,148,232 In addition to the type of repair employed, the rehabilitation progression is based on the size, depth, and location of the articular defect, the need for concomitant surgical procedures, and patient-related factors such as age, body mass index, health history, and preoperative activity level.
++
The goals during rehabilitation after articular cartilage repair are similar to those found for most knee rehabilitation programs presented in this chapter. Protected weight bearing over an extended period of time and early motion are essential after articular cartilage repair to promote maturation and maintain the health of the repaired or implanted cartilage. Special considerations for exercise and weight bearing associated with the various articular cartilage procedures are summarized in Box 21.2.12,93,137,148,232,298
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Total Knee Arthroplasty
++
Total knee arthroplasty (TKA), also called total knee replacement, is a widely performed procedure for advanced arthritis of the knee primarily in older patients (≥70 years of age) with osteoarthritis. However, during the decade between 1990 and 2000, the proportion of younger patients undergoing TKA increased significantly. During this period the proportion of knee replacements performed in the 40- to 49-year-old age group increased by 95.2% and in the 50- to 59-year-old age group by 53.7%. This indicates the criteria for TKA, traditionally reserved for the patient older than 65 years of age, have broadened.122
++
The primary goals of TKA are to relieve pain and improve a patient's physical function and quality of life.184,249
+++
Indications for Surgery
++
The following are common indications for TKA.119,160,249
++
Severe joint pain with weight bearing or motion that compromises functional abilities
Extensive destruction of articular cartilage of the knee secondary to advanced arthritis
Marked deformity of the knee such as genu varum or valgum
Gross instability or limitation of motion
Failure of nonoperative management or a previous surgical procedure
++
Prosthetic replacement of one or more surfaces of the knee joint began to develop during the 1960s. To address problems with early designs, semiconstrained, two-component designs evolved. For the patient with severe anterior knee pain resulting from advanced patellofemoral deterioration, a three-component, total condylar design that included resurfacing the patellofemoral joint was developed. For advanced arthritis of just the medial or lateral aspect of the knee, the unicompartmental (unicondylar) knee arthroplasty (UKA) was developed as an alternative to TKA.192,212,243,284
++
A therapist's knowledge of the different types of TKA and UKA used today enhances communication between the therapist and surgeon and provides a foundation for decisions made during rehabilitation.
++
Types of knee arthroplasty. Contemporary knee replacement procedures can be divided into several categories based on component design, surgical approach, and type of fixation (Box 21.3).120,160,189,192,249,284 One category is based on the number of components implanted or articulating surfaces replaced. Another is based on the degree of constraint (i.e., the amount of inherent congruency/stability in the design). Most TKA procedures today involve a two-component (bicompartmental), semiconstrained prosthetic system to replace the proximal tibia and distal femur (Fig. 21.8). These systems typically are composed of a modular or nonmodular femoral component with a metal articulating surface and a single all-polyethylene or metal-backed modular or nonmodular tibial component with a polyethylene articulating surface.120,160,249
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BOX 21.3 Total Knee Arthroplasty: Design, Surgical Approach, Fixation Number of Compartments Replaced
Unicompartmental: only medial or lateral joint surfaces replaced
Bicompartmental: entire femoral and tibial surfaces replaced
Tricompartmental: femoral, tibial, and patellar surfaces replaced
Implant Design Surgical Approach Implant Fixation Cemented
Uncemented
Hybrid
++
Occasionally, a tricompartmental design, which also resurfaces the posterior aspect of the patella with a polyethylene component, is selected if the patellofemoral joint is symptomatic.119,160,249 For the younger patient (< 55 years of age) with advanced disease of only the medial or lateral aspect of the knee joint, a unicompartmental design often is selected to replace just one tibial and one femoral condyle.192,212,243,249,284
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Intact medial and lateral collateral ligaments are necessary prerequisites for semiconstrained and unconstrained TKA.119,160,249 Fully constrained designs, now used infrequently, are reserved for the low-demand patient who has marked instability of the knee, extensive bone loss, or severe deformity or who has had previous TKA revisions.119,160 Contemporary fully constrained designs are not hinged but have inherent medial-lateral (ML) and anterior-posterior (AP) stability and some degree of rotation of the tibia on the femur to lessen the problem of progressive loosening of the prosthetic components over time.119,160
++
TKA designs also are classified as mobile-bearing or fixed-bearing. The most recent development in the evolution of TKA is the introduction of the mobile-bearing, bicompartmental prosthetic knee. A mobile-bearing knee has a rotating platform inserted between the femoral and tibial components whose top surface is congruent with the femoral implant (round-on-round articulation) but whose undersurface is flat for rotation and sliding of the tibial component (flat-on-flat articulation).38,189,249 A fixed-bearing knee does not have such an insert.60,249 The purpose of the mobile-bearing insert is to decrease long-term wear of the polyethylene tibial component. A mobile-bearing knee design is recommended most often for the active patient, younger than 55 to 65 years of age.249
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Another way to classify TKA design is based on the status of the posterior cruciate ligament (PCL). Designs are described as cruciate-retaining or cruciate-excising/substituting.119,160,208,211,249 Although the ACL is routinely excised during knee replacement—except with UKA—the PCL can be preserved or sacrificed. If the PCL is intact to provide posterior stability to the knee, one of several cruciate-retaining designs that require less congruency and allow some degree of AP glide can be used. If the PCL is irreparably deficient, a cruciate-excising/substituting prosthesis is selected. This type of design has inherent posterior stability from the congruency of the components, a posterior prominence in the tibial component, or a cam-post mechanism built into the design. Cruciate-retaining and cruciate-excising designs can have a fixed-bearing or mobile-bearing design.249
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Surgical approach. TKA and UKA procedures are also described in terms of the surgical approach employed.26,41,192,249 Since the inception of knee arthroplasty, an open approach requiring a relatively long anterior incision traditionally has been employed to provide sufficient exposure of the knee joint during the procedure. A recent advance is the development of minimally invasive knee arthroplasty.26,192 As with traditional joint arthroplasty, minimally invasive arthroplasty is an open procedure. However, minimally invasive TKA involves a smaller incision and less soft tissue disruption to reduce postoperative pain and increase the rate of postoperative recovery. Standard (traditional) and minimally invasive surgical approaches are described later in this section.
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Fixation. The method of fixation—cemented, uncemented, or "hybrid"—is another way to classify TKA procedures—that is, implants are held in place with acrylic cement, bone ingrowth (uncemented), or a combination of these two methods.160,210,231,297 Initially, almost all total knee replacements relied on cemented fixation. In fact, cemented fixation revolutionized knee arthroplasty.119,231 However, a long-term complication associated with early designs of cemented prostheses was biomechanical loosening, primarily of the tibial component at the bone-cement interface. Young, active patients were believed to be at highest risk for component loosening.297
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To address the problem of loosening, cementless (biological) fixation relying on rapid growth of bone into the surfaces of a porous-coated or beaded prosthesis was introduced and recommended primarily for the young, active patient.119,160,210,249,297 In addition, the use of a hydroxyapatite coating on the prosthesis has been advocated to enhance the ingrowth of bone.251 However, long-term follow-up demonstrated that although the femoral component reliably achieved fixation to bone tibial component, loosening occurred at an even higher rate with all-cementless fixation compared with cemented fixation.210,297 This finding gave rise to the "hybrid" TKA, which combines cemented fixation of the tibial component and cementless fixation of the femoral component.
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Currently, all-cemented fixation is used most often and all-cementless used least often. A surgeon's decision whether to employ hybrid fixation is based on the patient's age, bone quality, and expected activity level and the tightness of fit of the femoral component achieved during surgery.249 Design modifications to augment fixation of the tibial component (e.g., with pegs or screws) continue, although the long-term value of these design changes has yet to be determined.119,311
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In summary, research continues on the biomechanics of knee arthroplasty, modifications of designs, development of better methods of fixation and new materials with better wear qualities, as well as improved surgical techniques and use of sophisticated instrumentation for alignment and placement of prosthetic components. Ongoing developments in all of these areas will continue to contribute to the success of current-day and improvement of future TKA procedures.249,311
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One of several variations of standard or minimally invasive approaches with an incision along the midline or anteromedial aspect of the knee can be used. Key features of these two types of approaches are compared in Table 21.2.26,41,192,249 A quadriceps-splitting or a quadriceps-sparing approach is used to reach the capsule for an arthrotomy. The knee is flexed; and osteophytes, menisci, and the ACL are resected. If a posterior cruciate-substituting prosthesis is to be implanted, the PCL is also excised.
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A series of surgical techniques are performed prior to inserting the implants.120,249 Contemporary TKA employs computer-assisted, image-guided surgery to ensure precise placement and alignment of the components. Small portions of the distal femur and proximal tibia are removed and prepared for the implants. If a patellar implant is indicated, the patellar surface also is prepared and the prosthesis inserted. After trial components are inserted, soft tissue tension, collateral ligament balance, ROM, and patellar tracking are assessed. The lateral retinaculum may be released to improve patellar tracking.138,249 Permanent components are inserted, and the capsule and other soft tissues are repaired. The area is thoroughly irrigated, and the wound is closed with the knee positioned in extension and a small suction drain in place. A sterile dressing is placed over the incision, and the area is covered from foot to thigh with a compression wrap.
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Overall, the incidence of complications after TKA is low. Intraoperative complications during knee arthroplasty, such as an intercondylar fracture or damage to a peripheral nerve (e.g., the peroneal nerve), are uncommon. Because minimally invasive TKA is considered more technically challenging than conventional TKA, early reports suggest that the rate of intraoperative complications, such as fracture or malpositioning of an implant, is higher with a minimally invasive than a standard approach.26 An increased incidence of intraoperative technical errors, which can affect outcomes, is associated with patient obesity.124
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Early and late postoperative complications include infection, joint instability, polyethylene wear, and component loosening. As with arthroplasty of other joints, there is a risk of wound-healing problems and deep vein thrombosis (DVT) during the first few months after surgery. Although the incidence of deep periprosthetic infection is low, it is the most common reason for early failure and the need for revision arthroplasty. In contrast, polyethylene wear of the patellar and tibial components is the most common late complication requiring revision.52,191 The incidence of biomechanical loosening has been reduced significantly with the newer prosthetic designs and improved surgical techniques.191,250 If mechanical loosening develops over time, it occurs most often at the tibial component and more often with cementless or hybrid TKAs than fully cemented replacements.210
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Other postoperative complications that can compromise a patient's functional recovery include limited knee flexion, joint instability leading to subluxation,52,249 and patellar instability or tracking problems leading to impaired function of the extensor mechanism (most often an extensor lag).138,249 Additionally, obesity has been shown to limit outcomes in a patient's mobility after TKA compared to nonobese patients.124
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Postoperative Management
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Goals and interventions during progressive phases of postoperative rehabilitation after TKA are summarized in Table 21.3. Guidelines are similar for management after UKA. Interventions also may include preoperative patient education on an individual or group basis.251 Following surgery, patients routinely receive gait training and exercise instruction while hospitalized and in a subacute rehabilitation facility. Many patients also receive home-based or outpatient therapy after discharge from inpatient care.
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A patient is advanced from one phase of rehabilitation to the next based on an evaluation of their signs and symptoms and responses to selected interventions rather than solely at designated time periods. Accordingly, the timelines noted in Table 21.3 and described in the following sections are intended to serve only as general guidelines.
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NOTE: The postoperative guidelines in Table 21.3 and the following sections reflect recommendations for patients who have undergone primary TKA in which a standard surgical approach was used. The suggested timelines for the progression of exercises and weight bearing tend to be more rapid after UKA than TKA and minimally invasive compared with traditional arthroplasty but slower after complex revision arthroplasty versus primary arthroplasty.
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Immobilization and Early Motion
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Typically, after primary TKA, the knee is immobilized in a bulky compression dressing for a day, or sometimes continuous passive motion (CPM) is initiated in the recovery room or within a day after surgery. After complicated revision arthroplasty, an extended period of immobilization may be required. The position of immobilization after primary TKA is usually extension.249 Although uncommon, an alternative approach is to immobilize the knee in a 90° flexion splint immediately after surgery and for brief intervals during the next day or two to achieve knee flexion as soon as possible while maintaining knee extension with exercises.112
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During the initial postoperative period, it may be advisable to have a patient wear a posterior extension splint during ambulation until quadriceps control is reestablished. An extension splint also is indicated at night for a patient who is having difficulty achieving full knee extension after surgery or who had a significant preoperative knee flexion contracture.39,249
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In the past, CPM was used routinely during a patient's hospital stay after TKA.95 At that time, a number of studies describing the benefits of CPM, such as decreased need for postoperative pain medication, decreased incidence of deep vein thrombosis, and increased or more rapid recovery of ROM, were reported in the literature.126,151,171 However, in some of the investigations that reported greater ROM with CPM, the knees of patients in the control groups, who did not undergo CPM, were immobilized for several days to a week after surgery.126,171
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Customary practice for the past two decades has been to initiate early postoperative exercise except in some instances of complex revision arthroplasty.66
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FOCUS ON EVIDENCE
To evaluate postoperative CPM in the context of current practice, several randomized, controlled studies have been conducted comparing the effects of early postoperative exercise with and without the use of CPM after TKA.14,43,55,152 The results of these studies have demonstrated that although the addition of CPM in the recovery room or within a day after surgery increased the rate of return of knee flexion during the early postoperative period in one study,43 it provided no significant long-term benefits as to gains in ROM and functional mobility.
Although CPM continues to be used at the surgeon's discretion, the literature currently reflects that it is either no longer recommended after primary TKA55,210 or, if used, is recommended as an adjunct to—not a replacement for—a postoperative exercise program.14,43,55,152,249
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Weight-Bearing Considerations
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The extent to which weight bearing is allowable after primary TKA depends on the type of prosthesis implanted, the type of fixation used, the patient's age, size, and bone quality, and whether a knee immobilizer is worn during ambulation or transfers. With cemented fixation, weight bearing typically is permitted as tolerated immediately after surgery using crutches or a walker. During the first few days after surgery, use of a knee immobilizer may be required. The patient progresses to full weight bearing over a 6-week period.231
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With biological/cementless fixation, recommendations for weight bearing vary from permitting only touch-down weight bearing for 4 to 8 weeks while using crutches or a walker210 to weight bearing as tolerated within a few days after surgery while using crutches or a walker.39,249,251
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Cane use is indicated during progression from partial to full weight bearing. Ambulation without an assistive device, particularly during outdoor walking, is not advisable until the patient has attained full or nearly full, active knee extension and adequate strength of the quadriceps and hip musculature to control the operated lower extremity.39,160,210,251
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Goals and exercises for progressive phases of postoperative rehabilitation after current-day TKA, noted in Table 21.3, are discussed in the following sections.10,39,66,175,180,225,251,312 Precautions for exercise during rehabilitation are summarized in Box 21.4.
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Many of the exercises described for the early phase of rehabilitation were reported in a consensus document developed by physical therapists on the management of patients during the period of hospitalization after TKA.66 Prior to discharge from inpatient rehabilitation, a home exercise program serves as the foundation for the remainder of the rehabilitation process, with some patients also undergoing home-based or outpatient rehabilitation for a limited number of visits.
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Box 21.4 Exercise Precautions Following TKA
Monitor the integrity of the surgical incision during knee flexion exercises. Watch for signs of excessive tension on the wound, such as drainage or skin blanching.
Postpone SLRs in side-lying positions for 2 weeks after cemented arthroplasty and for 4 to 6 weeks after cementless/hybrid arthroplasty to avoid varus and valgus stresses to the operated knee.
Confer with the surgeon to determine when it is permissible to initiate exercises against low-intensity resistance. It may be as early as 2 weeks or as late as 3 months postoperatively.23a
If a posterior cruciate-sacrificing (posterior-stabilized) prosthesis was implanted, avoid hamstring strengthening in a sitting position to reduce the risk of posterior dislocation of the knee.39
Tibiofemoral joint mobilization techniques to increase knee flexion or extension may or may not be appropriate, depending on the design of the prosthetic components. It is advisable to discuss the use of these techniques with the surgeon before initiating them.
Postpone unsupported or unassisted weight-bearing activities until strength in the quadriceps and hamstrings is sufficient to stabilize the knee.
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Exercise: Maximum Protection Phase
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The focus of management during the first phase of rehabilitation and the acute/inflammatory and early subacute stage of tissue healing, which extends for about 4 weeks, is to control pain and swelling (with cold and compression), achieve independent ambulation and transfers while using a walker or crutches, prevent early postoperative medical complications, such as pneumonia and deep vein thrombosis, and minimize the adverse effects of postoperative immobilization. The goal is to attain 90° of knee flexion and full knee extension by the end of this first phase of rehabilitation. However, full knee extension may not be possible until joint swelling has subsided.
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It is well established that pain and joint swelling limit the function of the quadriceps muscle. In addition, there is a high correlation between quadriceps muscle weakness and impaired functional abilities during the initial period of recovery after TKA.182 Regaining quadriceps muscle strength, particularly in terminal extension, as early as possible after TKA is essential for functional control of the knee during ambulation and negotiating stairs. In addition to early postoperative exercise, neuromuscular electrical stimulation or biofeedback may be recommended as it has been shown to be safe when initiated as early as 2 days following surgery.8,180
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FOCUS ON EVIDENCE
A study by Mizner and co-investigators183 measured the voluntary activation and force-producing capacity of the quadriceps femoris muscle group in 52 patients (mean age, 64.9 years; range 49 to 78 years) 3 to 4 weeks after unilateral, cemented primary TKA for OA and in 52 healthy individuals (mean age, 72.2 years; range, 64 to 85 years) without knee pathology. All patients in the TKA group had participated in a standard exercise program following surgery. Force production (maximum voluntary isometric contraction) and volitional activation of the quadriceps muscle group of the operated limb were, respectively, 64% and 26% less in the TKA group than in the healthy group. There was a weak relationship (r2=0.17) between these results and postoperative knee pain. There were no significant differences in quadriceps muscle force production and volitional activation of the noninvolved knees in the TKA group compared with the healthy group. Based on the results of their study, the investigators recommended the use of neuromuscular electrical muscle stimulation or biofeedback as an adjunct to an individualized postoperative exercise program to augment quadriceps muscle force production after TKA.
Results of a prospective, randomized, controlled study conducted by Avramidis and colleagues8 support the use of neuromuscular electrical stimulation in addition to a postoperative exercise program after TKA. Thirty patients scheduled to undergo primary TKA were randomly assigned to two groups (15 patients per group). Postoperatively, patients in both groups underwent an individualized program of exercise and gait training. In addition, the treatment group received electrical stimulation to the vastus medialis muscle 4 hours a day for 6 weeks beginning on postoperative day two. Patients in the electrical stimulation group demonstrated a significantly faster walking speed than those in the control group at 6 weeks and 12 weeks postoperatively.
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Goals and interventions. The following goals and exercise interventions are included in the initial phase of rehabilitation after TKA.10,39,66,175,180,251,312
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Prevent vascular and pulmonary complications.
Control pain and swelling.
Minimize reflex inhibition or loss of strength of knee and hip musculature.
Muscle-setting exercises of the quadriceps (preferably coupled with neuromuscular electrical stimulation), hamstrings, and hip extensors and abductors
Active-assisted and active straight leg raise (SLR) exercises in supine and prone positions the first day or two after surgery, postponing SLRs in side-lying positions for as long as 2 weeks after cemented TKA and for as long as 4 to 6 weeks after cementless/hybrid replacement to avoid varus or valgus stresses to the operated knee
Active-assisted ROM (A-AROM) progressing to active ROM (AROM) of the knee while seated and standing for antigravity knee extension and flexion, respectively.
As weight bearing on the operated lower extremity permits, terminal knee extension in standing, wall slides in a standing position, minisquats, and partial lunges to develop control of the knee extensors and reduce the risk of an extensor lag
Maintain or improve strength of the contralateral lower extremity.
Regain knee ROM.
Heel-slides in a supine position or while seated with the foot on the floor to increase knee flexion
Neuromuscular facilitation and inhibition technique, such as the agonist-contraction technique (described in Chapter 4), to decrease muscle guarding, particularly in the quadriceps, and increase knee flexion
Gravity-assisted knee flexion by having the patient sit and dangle the lower leg over the side of a bed
Gravity-assisted or self-assisted knee extension in the supine or long-sitting position by periodically placing a rolled towel under the heel and leaving the knee unsupported or in a seated position with the heel on the floor and pressing downward just above the knee with both hands
Gentle inferior and superior patellar gliding techniques to prevent restricted mobility
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PRECAUTION: Avoid placing a pillow under the knee while lying supine or while seated with the operated leg elevated to reduce the risk of developing a knee flexion contracture.
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Improve trunk stability and balance.
Reestablish functional mobility.
Gait training adhering to weight-bearing restrictions with use of appropriate assistive device
Functional training (bed mobility, sit-to stand transfers, basic ADL)
Criteria to progress. The criteria to progress to the intermediate phase of rehabilitation include the following.
Minimal swelling and pain
Well-healed incision with no signs of infection
Independent basic ADL and ambulation with appropriate assistive device
AROM approaching full or nearly full, active knee extension and 90° knee flexion
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Exercise: Moderate Protection/Controlled Motion Phase
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The emphasis of the intermediate phase of rehabilitation, which begins at about 4 weeks and extends to 8 to 12 weeks postoperatively, is to achieve approximately 110° knee flexion and active knee extension to 0° and gradually to regain lower extremity strength and muscular endurance, balance, cardiopulmonary endurance, and additional functional mobility.
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By 4 to 6 weeks postoperatively, if nearly full knee extension has been achieved and the strength of the quadriceps is sufficient, most patients transition to using a cane during ambulation activities. This makes it possible to focus on normalizing the patient's gait, sit-to-stand, and stair ascent and descent patterns and improving the speed and duration of walking. In general, most improvements in a patient's functional abilities and quality of life tends to occur by 3 months postoperatively.127
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Goals and interventions. The goals and exercise interventions for the intermediate phase of rehabilitation are the following.10,39,66,175,182,225,251,312
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Increase strength and endurance of knee and hip musculature.
Multiple-angle isometrics and low-intensity dynamic resistance exercises of the quadriceps, hamstrings, and hip musculature (extensors, abductors, external rotators) against a light grade of elastic resistance or a cuff weight around the ankle
Resisted SLRs in various positions to increase the strength of hip and knee musculature
As weight bearing allows, continue or begin closed-chain exercises including resisted terminal knee extension in standing, standing wall slides, minisquats, partial lunges, and the sit-to-stand task emphasizing proper lower extremity alignment. Include scooting forward and backward on a wheeled stool to improve functional control of the knee.
Add forward and backward, progressing to lateral step-ups and step-downs (initially using a low step and increasing the height of the step). Reinforce proper lower extremity alignment. To progress, perform step-ups against elastic resistance.
Stationary cycling with the seat positioned as high as possible to emphasize knee extension
Include strengthening exercises for the nonoperated lower extremity
Continue to increase knee ROM.
Low-intensity self-stretching using a prolonged stretch or hold-relax technique to increase knee flexion and extension if limitation persists. Flexibility of the hip flexors, hamstrings, and calf muscles also may need to be increased for standing and ambulation activities.
Stationary cycling with seat lowered to increase knee flexion
Grade III inferior or superior patellar mobilization techniques to increase knee flexion or extension, respectively, if insufficient patellar mobility is restricting ROM
Improve standing balance and trunk stability.
Trunk stabilization exercises
Proprioceptive and balance training progressing from bilateral to unilateral stance on stable surface, then to balance activities on an unstable surface
Functional reaching activities while standing or stooping
Tandem walking, grapevine walking initially in parallel bars for safety (See Chapter 23 for additional activities.)
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PRECAUTION: A progression of balance activities for patients with TKA is typically safe to begin about 8 weeks postoperatively but must be based on the ability to control the knee during stance, weight-bearing restrictions, and the absence of pain.225
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FOCUS ON EVIDENCE
Following TKA or UKA, patients often report difficulty kneeling or the inability to kneel even a year after surgery. Although many functional activities, such as housework and gardening, involve kneeling, patient education about this skill often is not included in postoperative rehabilitation. Jenkins and associates125 conducted a single-blind, prospective, randomized, controlled study to investigate the impact of kneeling instruction following partial knee replacement. All patients participated in postoperative rehabilitation, but at 6 weeks after surgery, only half received a single physical therapy intervention of advice and instruction on kneeling. At 1 year following surgery, patient-reported kneeling ability was significantly better in the group who received kneeling advice and instruction than in the group that did not. As such, the investigators suggested that kneeling advice and instruction should be included in postoperative rehabilitation after partial knee replacement. Although the findings of this study may have implications for patients who have undergone TKA, the investigators pointed out that the results of the study can be applied to patients following only partial knee replacement.
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Criteria to progress. The following criteria typically must be met to progress to the final phase of rehabilitation following TKA.
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AROM: full knee extension (no extensor lag), 110° knee flexion
Quadriceps/hamstring and hip muscle strength: at least 70% (or 4/5 muscle testing grade) compared to uninvolved leg
Minimal to no pain during exercises and ambulation with or without a cane
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Exercise: Minimum Protection/Return to Function Phase
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Beginning at approximately 8 to 12 weeks and beyond after surgery, the emphasis of the final phase of rehabilitation is on task-specific strengthening exercises, proprioceptive and balance training, advanced functional training (see Chapter 23), and continued cardiopulmonary conditioning so that the patient develops the strength, power, balance, and endurance needed to return to a full level of functional activities in the community. (Refer to Table 21.3 for a summary of goals and interventions during the final phase of rehabilitation.)
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Despite persistent strength and power deficits, altered movement patterns and insufficient speed and endurance during functional activities, patients often are discharged from supervised therapy 2 to 3 months postoperatively after attaining functional ROM of the knee and the ability to ambulate independently with an assistive device. However, deficits in physical function have been shown to persist for an average of 10 months291 to a year or more after surgery.182
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It is likely that some patients, especially those living in the community, could benefit from an intensive exercise program during the late phases of rehabilitation to perform demanding physical activities more efficiently, such as ascending and descending stairs and returning to selected recreational activities.
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FOCUS ON EVIDENCE
Moffet and associates184 conducted a single-blind, randomized, controlled study to determine the effectiveness of an intensive, supervised functional training program initiated 2 months after primary TKA for OA. Patients in the experimental group (n=38) participated in facility-based, twice-weekly, 60- to 90-minute exercise sessions consisting of hip and knee strengthening exercises, task-specific functional exercises, and aerobic conditioning. These exercises were preceded by a warm-up and followed by a cool-down period. The full cohort of exercises was phased in gradually during the first 2 weeks of the program. Patients also received a home program to be followed on the days they did not participate in the supervised program. Patients in the control group (n=39) participated in a home exercise program for 6 weeks with periodic home visits by a therapist. No exercise-related adverse events occurred during the study.
Patients were evaluated by means of the 6-minute walk test and two functional outcome and quality-of-life (QOL) measures prior to beginning the exercise program (baseline measurement at 2 months after surgery), at the conclusion of the 6-week exercise program, and at 6 and 12 months postoperatively. The two groups were comparable at baseline. At the conclusion of the intervention and at the 6- and 12-month follow-ups, patients in the intensive exercise group walked significantly longer distances (walked at a faster speed) during the 6-minute walk test than did those in the control group. Functional abilities and QOL measures also were significantly better for the intensive exercise group than the control group immediately after the 6-week program and at 6 months postoperatively. At 1 year after surgery there were no significant differences in function or QOL measures between the two groups.
The investigators concluded that an intensive, functionally oriented exercise program initiated 2 months after primary TKA was safe and effective for improving physical function and quality of life.
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With the trend toward an increasing number of young (< 60 years of age) and active patients undergoing TKA,122 patient education is essential to help patients understand the detrimental effects of repetitive, high-impact activities (work-related, fitness-related, recreational) on the prosthetic implants and to learn how to select activities that promote fitness but are least likely to reduce the longevity of the prosthetic knee.106,139,169 Accordingly, patients are advised to participate in low-impact physical activities after TKA to reduce the risk of component wear and mechanical loosening over time and the premature need for revision arthroplasty.
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For the patient who wishes to participate in athletic activities after TKA, there are a number of considerations. Factors that influence participation include the level of demand (intensity and load) of an athletic activity, a patient's body weight, overall level of fitness, and preoperative experience with the activity and the technical quality of the knee replacement and related soft tissue balancing or reconstruction.106,139
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Physical activities for fitness and recreation that are highly recommended, recommended with caution, or not recommended after TKA are noted in Box 21.5.106,139,169
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Outcomes
Although the ideal knee replacement that replicates the normal biomechanics of the native knee joint has yet to be developed, knee arthroplasty has been shown to be a successful procedure for patients with advanced joint disease. Extensive research has been published in the orthopedic literature on patient-related outcomes and the survivorship associated with a wide variety of prosthetic designs, surgical techniques, methods of fixation, and types of materials.119,120,154,249,311 Because of the variability of procedures and the fact that outcomes are often based on nonrandomized, retrospective studies, it has been difficult to draw general conclusions.250 However, a recent large-scale (2,352 patients), multicenter, randomized study comparing patient-related outcomes following three variations of total knee component designs demonstrated no significant differences in clinical, functional, and quality of life improvements in the randomized groups at 2 years following surgery.127
Patient-related outcomes after knee arthroplasty that have the most influence on patient satisfaction are relief of pain and an improved ability to perform necessary and desired functional activities for an extended number of years. Approximately 90% of patients who undergo primary TKA can expect 10 to 20 years of satisfactory function before revision arthroplasty may need to be considered.249 For example, Dixon and colleagues60 reported a 92.6% survival rate of modular, fixed-bearing TKA in patients followed for a minimum of 15 years.
Parameters typically measured by means of self-report and performance-based instruments to determine the success of knee replacement surgery are the level of pain, overall QOL, knee ROM, strength of the knee musculature, and a patient's ability to perform functional activities safely and with ease. An understanding of evidence-based outcomes following TKA can assist a therapist in developing realistic goals with a patient and better determining a patient's prognosis.
Pain relief. Almost all patients who undergo knee arthroplasty report a significant reduction of pain during knee motion and weight bearing, with most patients reporting good to excellent pain relief.86,249,250,293
ROM. Improvements in knee ROM are not as predictable as relief of pain. Stiffness often persists after the initial recovery from surgery has occurred.86 However, it also has been reported that ROM may continue to improve as many as 12 to 24 months postoperatively.265 Factors that influence postoperative ROM include preoperative ROM, the underlying disease, obesity, postoperative pain, and whether a primary or a revision arthroplasty was performed. Complications such as component malpositioning, inadequate soft tissue balancing or reconstruction, infection, and mechanical loosening of an implant can adversely affect postoperative ROM.215,262
Patients with restricted ROM preoperatively often continue to have limited knee flexion, extension, or both postoperatively despite an aggressive postoperative exercise program.262,265 In fact, the most important predictor of long-term postoperative knee ROM is preoperative ROM.145,248,262 For example, in a study of 358 patients who underwent primary TKA for OA, total ROM of the knee was 110° preoperatively and 113° postoperatively due to a reduction in the average knee flexion contracture from 12° to 9°.248 The results of several other studies found that despite patients' participation in an outpatient or home-based postoperative rehabilitation program, there was no significant change in preoperative versus postoperative knee ROM at 6 months10,182 or at 12 months after surgery.230
Differences in prosthetic design, such as mobile-bearing versus fixed-bearing38,249 or PCL-retaining versus PCL-substituting (posterior stabilized) designs,208,211,249 and in the method of fixation210,249 do not appear to affect ROM outcomes after primary TKA. A comparison of five designs of posterior cruciate-substituting implants, for example, showed no significant differences in the extent of improvement of knee ROM among designs.248
Limited knee ROM has a substantial impact on postoperative function, particularly if knee flexion is less than 90° and knee extension is limited by more than 10° to 15°.249 With less than 90° to 100° of knee flexion, it is difficult to negotiate stairs, and having less than 105° makes it difficult to stand up from a standard height chair without using arm support.249 In a retrospective study of more than 5,000 total knee arthroplasties, Ritter and associates237 determined that an even greater degree of knee flexion was necessary for optimal postoperative function. Results of their study indicated that functional outcomes were highest when at least 128° of knee flexion was achieved following surgery but were substantially compromised if < 118° was achieved. In contrast, lack of full knee extension because of contracture or an extensor lag is thought to be a source of a patient's perception of knee pain or instability during ambulation activities, particularly when ascending and descending stairs.138,249
Strength and endurance. It takes a minimum of 3 to 6 months after surgery for a patient to regain strength in the quadriceps and hamstrings of the operated knee to a preoperative level.138,182,265 Quadriceps weakness tends to persist longer after knee arthroplasty than does knee flexor weakness.265 Furthermore, quadriceps weakness of the contralateral (nonoperated) side is a predictor of impaired functional outcomes at 1 and 2 years following unilateral TKA.312
Studies of patients after unilateral TKA with a conventional surgical approach have demonstrated that quadriceps strength in the operated leg correlates highly with performance on tests of functional abilities during the first 6 months after surgery.182 For example, a study by Farquhar and associates70 demonstrated that at 3 months post-TKA, patients had quadriceps weakness and an altered sit-to-stand movement pattern reflected by the use of increased hip flexion and greater reliance on hip extensor strength, thus reducing the demand on the knee extensors when rising from a chair. Of additional interest was the finding that at 1 year after surgery, despite improved symmetry of quadriceps strength, the altered sit-to-stand pattern persisted, perhaps as the result of habit.70
Quadriceps strength is also significantly less than in similarly aged healthy individuals 6 months to a year after surgery72,86,182,293 and the noninvolved leg 1 to 2 years postoperatively.242,263 It has been suggested that eversion of the patella during a conventional surgical approach may contribute to impaired function of the quadriceps mechanism after surgery.154,263
Given the number of studies that have identified significant quadriceps weakness after TKA and the high correlation between quadriceps strength and functional performance, there is substantial evidence to support the importance of quadriceps-strengthening exercises in postoperative rehabilitation programs to optimize function after TKA.
Physical function and activity level. The greatest and most rapid improvements in physical performance following TKA occur during the first 12 weeks with an additional but small amount of improvement occurring beyond 12 weeks.132 Relief of pain appears to significantly improve a patient's QOL and ability to perform functional activities. However, just 1 month after TKA, functional performance is dramatically worse than the preoperative level of function, despite a patient's participation in a rehabilitation program the day after surgery.10
A systematic review of the literature by Ethgen and colleagues69 revealed that a patient's postoperative level of function and QOL, as measured by self-report questionnaires, typically begins to surpass the preoperative level at approximately 3 months, with most improvement in function occurring by 6 months. However, results of some studies have shown that additional improvements may occur for a year or more postoperatively.265,293
Overall, when comparing preoperative with postoperative function, patients with high preoperative scores on functional measures achieved a higher level of function postoperatively than patients with low preoperative functional scores.80
A survey by Weiss and colleagues296 of 176 patients (mean age, 70.5 years) 1 year or more after TKA identified patients' level of participation in activities of graduated difficulty and determined which activities were most important to patients. The survey also identified activities that were difficult after TKA. The results of the survey indicated that in addition to basic activities of daily living (ADL)—walking, stair-climbing, personal care—patients performed a wide range of therapeutic and recreational activities after TKA. The activities in which the highest percentage of patients participated were stretching exercises (73%), leg-strengthening exercises (70%), gardening (57%), and stationary cycling (51%). These same activities were rated as important by patients. Functions that were the most difficult and most often caused knee pain were squatting (75%) and kneeling (70%).
Bradbury and colleagues28 studied the pre- and postoperative sports participation of 160 patients who had undergone TKA 5 years earlier. Preoperatively, there were no significant differences in knee ROM, walking abilities, and radiographs in the patients who did and did not participate in sports activities. Postoperatively, the investigators found that 51 (65%) of the 79 patients (mean age, 73 years at the 5-year follow-up) who had regularly (at least twice a week) participated in sports activities during the year prior to surgery were participating in some type of sport at the 5-year follow-up. Patients were more likely to return to low-impact rather than high-impact activities. Of the patients who did not regularly participate in a sport before surgery, none took up a sport postoperatively.
Despite an overall positive impact of TKA on physical function, long-term studies indicate that functional abilities typically remain below norms for age-matched, healthy populations.10,72,80 A follow-up study of 276 community-dwelling patients 6 months after primary TKA revealed that overall physical function improved significantly for all patients, although 60% reported moderate to extreme difficulty descending stairs and 64% continued to have a similar degree of difficulty with heavy household tasks.128
Results of another study indicated that 1 year after TKA, despite a relative absence of pain and some improvement in functional abilities, significant deficits in strength and function were apparent when compared with the abilities of age-matched, healthy individuals.293 The post-TKA patients had less strength of the knee musculature, slower walking and stair-climbing speeds, and a higher perceived level of exertion during activities than healthy individuals. The authors pointed out that the post-TKA patients as a group were heavier than the control group and suggested that general physical deconditioning may have contributed to the postoperative group's functional limitations. This study emphasized the need for inclusion of a low-impact aerobic conditioning program during rehabilitation after TKA.
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BOX 21.5 Recommendations for Participation in Physical Activities Following TKA Highly Recommended
Recommended If Experienced Before TKA Not Recommended
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Patellofemoral Dysfunction: Nonoperative Management
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Related Patellofemoral Pathologies
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Historically, the differential diagnosis of patellofemoral (PF) pathologies has been plagued with confusion, largely related to the use of broadly inclusive terminology such as chondromalacia patellae and patellofemoral pain syndrome (PFPS). In an attempt to more clearly identify the anatomical structures involved and the biomechanical changes leading to dysfunction, several classification systems have been proposed. These classifications include guidelines for intervention based on impairments and activity limitations.115,302
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Instability includes subluxation or dislocation of a single or recurrent episode. There may be an abnormal Q-angle, dysplastic trochlea (shallow groove or flat lateral femoral condyle), patella alta, tight lateral retinaculum, and inadequate medial stabilizers (vastus medialis oblique muscle [VMO] and medial patellofemoral ligament [MPFL]). There may be associated fractures. Usually the instability is in a lateral direction. The dislocation may derive from direct trauma to the patella or from a forceful quadriceps contraction while the foot is planted and the femur is externally rotating while the knee is flexed. Recurrent dislocation is usually an indication for surgery to redirect the forces through the patella.
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PF Pain with Malalignment or Biomechanical Dysfunction
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Patellofemoral pain reportedly due to malalignment or biomechanical dysfunction includes impairments that cause an increased functional Q-angle such as femoral anteversion, external tibial torsion, genu valgum, or foot hyperpronation. There may be a tight lateral retinaculum, weak VMO muscle, neuromuscular deficits in the hip musculature, incompetent MPFL, patella alta, patella baja, generalized laxity, or dysplastic femoral trochlea. There is usually abnormal patellar tracking, and there may be discordant firing of the quadriceps muscle.115
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CLINICAL TIP
Although it is widely reported that PF malalignment is seen in patients with PFPS and may be a precursor of or may contribute to symptoms, the evidence to support the existence of abnormal alignment in PFPS is lacking. Specifically, because there is little evidence to support the validity and reliability of various testing procedures currently used to measure patellar position and tracking, whether performed in weight-bearing or nonweight-bearing positions, only assumptions can be made as to the presence of malalignment in PFPS.306
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PF Pain Without Malalignment
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Patellofemoral pain without malalignment includes many subcategories of lesions that cause anterior knee pain.
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Soft tissue lesions. Soft tissue lesions include plica syndrome, fat pad syndrome, tendonitis, IT band friction syndrome, and bursitis.
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Plica syndrome describes a condition related to irritation of remnants of embryological synovial tissue around the patella. With chronic irritation, the tissue becomes an inelastic, fibrotic band that is tender during palpation. When acute, the tissue is painful during palpation. The band is usually palpable medial to the patella, although there are variations in its location.23,131
Fat pad syndrome involves irritation of the infrapatellar fat pad from trauma or overuse.
Tendonitis of the patellar or quadriceps tendons, sometimes called jumper's knee, typically occurs from overuse as the result of repetitive jumping. Tenderness occurs along the attachment of the tendon to the patella. Symptoms may be exacerbated secondary to tightness quadriceps.294
IT band friction syndrome is irritation of the IT band as it passes over the lateral femoral condyle. Contributing factors could be tight tensor fasciae latae or gluteus maximus (see discussion in Chapter 20). Because the IT band attaches to the patella and lateral retinaculum, it may cause anterior knee pain.
Prepatellar bursitis, also known as housemaid's knee, is the result of prolonged kneeling or recurrent minor trauma to the anterior knee. When inflamed, there may be restricted motion due to swelling and pain caused by direct pressure or pressure from the patellar tendon.
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Tight medial and lateral retinacula or patellar pressure syndrome. There is increased contact pressure of the patella in the trochlear groove.
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Osteochondritis dissecans of the patella or femoral trochlea. Osteochondral lesions result in pain on the retro surface of the patella that is worse during squatting, stooping, ambulating, and descending steps. The knee may give way or lock. There may be loose bodies within the joint.
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Traumatic patellar chondromalacia. With chondromalacia, there is softening and fissuring of the cartilaginous surface of the patella, which is diagnosed with arthroscopy or arthrography.115 It may eventually predispose the joint to degenerative arthritis or basal degeneration of the middle and deep zones of the cartilage.94 Causes of degeneration may include trauma, surgery, prolonged or repeated stress, or lack of normal stress such as during periods of immobilization.209
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PF osteoarthritis. Osteoarthritis may be idiopathic or post-traumatic and is diagnosed by radiographic changes consistent with degeneration.
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Apophysitis. Osgood-Schlatter disease (traction apophysitis of the tibial tuberosity) and Sinding-Larsen Johansson syndrome (traction apophysitis on the inferior pole of the patella) occur during adolescence as a result of overuse during rapid growth. They are self-limiting conditions.
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Symptomatic bipartite patella. Most bipartite patellae (due to patellar ossification variants) are asymptomatic, but trauma may disrupt the chondro-osseous junction leading to symptoms.115
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Trauma. Trauma includes tendon rupture, fracture, contusion, and articular cartilage damage that results in inflammation, swelling, limited motion, and pain with dysfunction whenever contracting the quadriceps, such as during stair climbing, squatting, and resisted knee extension.
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The cause of anterior knee pain may be direct trauma, overuse, faulty patellar tracking from malalignment due to anatomical variations or soft tissue length and strength imbalances in the hip, knee, or ankle/foot; degeneration; or a combination of these factors.33,61,166,227,228,245,260,292,294,308 An attempt should be made to determine the causative factors based on the patient's history and a comprehensive and sequential examination.
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Consensus on Factors Leading to PF Symptoms
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A consensus statement summarizing input from leaders and researchers studying PF pain categorized factors leading to PFPS into local, distal, and proximal influences. The following are examples of these factors.54
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Local factors. Local factors include structures around the joint itself, such as infrapatellar fat pad, ligaments, quadriceps tendon, medial and lateral retinaculum, and subchondral bone. Symptoms may be provoked by faulty mechanics. Walking and squatting increase PF joint stress.
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Distal factors. Factors arising from the foot include an externally rotated foot during relaxed stance, rearfoot eversion at heel strike, delayed or prolonged rearfoot eversion during walking and running, and increased midfoot mobility.
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Proximal factors. Factors arising from the hip region include altered hip kinematics of increased hip adduction and internal rotation during specific tasks such as running and single-limb activities of squatting, jumping, and drop landing. These may be associated with hip abductor and eternal rotator muscle weakness.
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Common Impairments, Activity Limitations, and Participation Restrictions
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Structural and functional impairments. Impairments that may be associated with PF dysfunction include the following.33,61,142,166,224,227,228,245,260,290,292,294,308
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Pain in the retropatellar region
Pain along the patellar tendon or at the subpatellar fat pads due to irritation
Patellar crepitus; swelling or locking of the knee
Altered lower extremity alignment (Fig. 21.9), specifically increased hip adduction and internal rotation and dynamic knee valgus (valgus collapse) that occurs during weight-bearing activities, such as ascending and descending stairs, squatting, or landing after a jump121,172,227,228,229,238,271
Weakness of the hip abductor, external rotator, and/or extensor muscles24,121,172,224,227-228,238,271
Weakness, inhibition, or altered recruitment or timing of firing of the VMO muscle49
Decreased flexibility of the tensor fasciae latae, hamstrings, quadriceps, or gastrocnemius and soleus muscles224,227
Overstretched medial retinaculum
Restricted lateral retinaculum, IT band, or fascial structures around the patella
Decreased medial gliding or medial tipping of the patella
Pronated foot
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FOCUS ON EVIDENCE
There are a substantial number of studies that have found altered lower extremity kinematics and/or strength and activation deficits of hip musculature in individuals (primarily females) with versus those without PF pain.24,121,172,224,227,228,229,238,271 Overall, the findings of most of these studies have revealed greater hip adduction and/or internal rotation during weight-bearing activities that involve knee flexion, such as squatting, ascending or descending stairs, or landing from a jump, in individuals with PF pain compared with noninvolved controls. Decreased strength of hip extensors, external rotators, and/or abductors, typically measured during a maximum voluntary isometric contraction, has also been identified in those with PF pain.
It is important to point out that the results of studies have not been consistent. For example, the association between weakness of specific hip muscles in individuals with PFPS and abnormal lower extremity kinematics is not absolute. McKenzie and colleagues172 reported diminished strength of hip extensors, abductors, and external rotators, as well as excessive hip adduction and internal rotation during stair descent and ascent. Souza and colleagues271 also reported that females with PFPS had significantly decreased strength of the hip extensors and abductors and excessive internal rotation but not increased hip adduction during step-down movements, a drop-jump, and running. In contrast, Bolgla and colleagues24 identified weakness of the hip abductors and external rotators in females with PFPS but no evidence of abnormal hip kinematics during stair descent. The inconsistent findings may be attributed to a number of factors including differences in weight-bearing tasks and measurement techniques.
Although these studies suggest that an interdependence exists between the knee and more proximal regions of the body, specifically the hip, pelvis, and trunk, it is also important to recognize that because of the retrospective nature of these studies, the findings demonstrate associations—not cause-and-effect relationships—among altered hip mechanics, deficits in hip muscle performance, and signs and symptoms of PF dysfunction.109,227,229
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Activity limitations and participation restrictions. Limitations and restrictions associated with the impairments include the following.
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Limited performance of basic ADL as the result of pain or poor knee control (valgus collapse)
Pain-related limitations of functional mobility (e.g., reduced ability to get in or out of a chair or car, ascend and descend stairs, walk, jump, or run) that are necessary to carry out ADL and IADL, work, and community, recreational, or sport activities
Inability to maintain prolonged flexed knee postures, such as sitting or squatting, as the result of pain and stiffness in the knee
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Patellofemoral Symptoms: Management—Protection Phase
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When symptoms are acute, treat them as any acute joint problem—with modalities, rest, gentle motion, and muscle-setting exercises in pain-free positions. Pain and joint effusion inhibit the quadriceps,279 so it is imperative to reduce irritating forces. Splinting the patella with a brace or tape may unload the joint and relieve the irritating stress.
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Patellofemoral Symptoms: Management—Controlled Motion and Return to Function Phases
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When signs of acute pain and inflammation are no longer present, management is directed toward correcting or modifying the biomechanical factors that may be contributing to the impairment. Because no one factor or combination of factors has been identified as the direct cause or effect of PF pain symptoms, it is imperative to develop interventions that address the scope of impairments identified during the examination.228 It is also important to integrate the concept of regional interdependence in the application of exercise interventions by addressing proximal weakness and tightness, impaired stability, and distal malalignment that may place excessive stress through the PF joint.109,227
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Management during the controlled motion and return to function phases of rehabilitation typically emphasizes increasing strength, dynamic control, and pain-free mobility of the knee and hip; modifying abnormal movement strategies that may contribute to impairments; and improving stability of the pelvis and trunk, balance, and functional abilities.
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Instructions. Because end-range stress and prolonged postures tend to exacerbate symptoms, instruct the patient to avoid positions and activities that provoke the symptoms.
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Minimize or avoid stair climbing and descending until the hip and knee muscles are strengthened to a level at which they can control knee function without symptoms.
Do not sit with the knees flexed excessively for prolonged periods. During sitting, periodically perform ROM of the knee to relieve stasis.
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Home exercise program. Implement a home exercise program to reinforce supervised training. Prior to discharge, provide instructions for a safe progression of exercises and functional activities.
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Increase Flexibility of Restricting Tissues
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Identify any structures that could be contributing to faulty mechanics and establish a stretching program. The gastrocnemius, soleus, quadriceps, hamstring, and tensor fasciae latae (TFL) muscles have been identified as specific muscles with reduced flexibility in individuals with patellofemoral dysfunction.224,227,290 Self-stretching techniques are described in the exercise section of this chapter. Techniques to stretch the two-joint muscles that cross the hip and knee are described in Chapter 20, and those that cross the knee and ankle are described in Chapter 22.
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Because restrictions related to insertion of the IT band and the lateral retinaculum may contribute to decreased patellar mobility and faulty patellar tracking in some patients with PFPS, specific techniques to address these impairments are described in this section.
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Patellar mobilization: medial glide. Position the patient side-lying. Stabilize the femoral condyles with one hand under the femur, and glide the patella medially with the base of the other hand (Fig. 21.10).97 There is usually greater mobility with the knee near extension; progress by positioning the knee in greater flexion prior to performing the medial glide.
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Medial tipping of the patella. Position the patient supine. Place the thenar eminence at the base of the hand over the medial aspect of the patella. Apply a posterior force to tip the patella medially. While the patella is held in this position, apply friction massage with the other hand along the lateral border (Fig. 21.11). Teach the patient to self-stretch in this manner.
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Patellar taping. Although the use of patellar taping to realign the patella and provide a prolonged stretch has been recommended in early resources,97,166 the primary benefit of taping identified in two systematic reviews of the literature22,49 is the reduction of anterior knee pain during provoking activities. However, it is not clear whether pain relief is the result of patellar realignment from taping.
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FOCUS ON EVIDENCE
A multicenter, single-blind study demonstrated little to no change in patellar alignment as the result of three different patellar taping techniques. A decrease of symptoms in 71 subjects with PFPS did occur, but the reduction of symptoms occurred regardless of the direction in which the tape was applied.305 The investigators suggested that taping may alter proprioceptive input and increase tolerance to functional training and therefore should be used while the focus of treatment addresses proximal weakness.
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Improve Muscle Performance and Neuromuscular Control
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Because many possible diagnoses fall under the category of PFPS, various biomechanical influences may be the precipitating or perpetuating cause of the symptoms. Impaired strength, endurance, and control of the knee extensors and hip musculature (extensors, external rotators, and abductors), as well as impaired stability of the trunk and pelvis, must be addressed.227,228,229
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However, not all patients with PF symptoms benefit from the same exercises. Consequently, it is imperative that the therapist design a progression of exercises that addresses the specific impairments of each patient. Exercises to improve muscle performance and functional control in associated regions proximal and distal to the knee are described in Chapters 16, 20, and 22, respectively. Additional lower extremity exercises are described in Chapter 23.
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VMO Emphasis: A Closer Look
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Although it is not possible to isolate contraction of the VMO, it is accepted that the line of pull of this component of the quadriceps muscle influences the tracking of the patella. Consequently, one aspect of management traditionally has been directed toward developing awareness of the VMO contraction during quadriceps muscle activation. Tactile cues over the muscle belly, electrical stimulation, or biofeedback can be implemented to reinforce the VMO contraction during knee extension exercises.
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It is now well accepted that exercise programs for patients with PFPS should target regions proximal to the knee.85,161,195,290 However, substantial attention also has been given to the need for activating the VMO through various weight-bearing and nonweight-bearing exercises and functional activities.6,49,61,166 As discussed in this section, however, evidence is inconsistent regarding the onset timing and activation of the VMO in individuals with and without PFPS, the role of the VMO/VL ratio, and the effectiveness of various nonweight-bearing and weight-bearing exercises and functional activities to promote VMO activation.49,116,130,142,165,269,292 Evidence about selected exercises is summarized in the following section, but further investigation is warranted.
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Nonweight-Bearing (Open-Chain) Exercises
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NOTE: There is controversy regarding compressive forces and stress on the PF joint with open-chain exercises.67,96 The type of resistance (constant, variable, or isokinetic) places different demands on the quadriceps muscle in terms of maximum effort at various ranges. The resultant force from the quadriceps tendon and patellar tendon and the patellar contact area also vary through the ROM. Therefore, the stress on the articulating surface of the patella varies. There is little or no contact of the patella with the trochlear groove from 0° to 15° of flexion,67 so pain felt in that range could derive from irritation of the patellar fat pads or synovial tissue. Greatest patellar stress is at 60° and compression loads at 75°, so pain may be provoked in these ranges when maximum torque from the resistance force is applied in these ranges.67 Where the pathology is located affects where in the range the patient feels pain.96 It is recommended that when examining the patient, the range where pain is felt be noted and resistance loads that cause pain in that range be avoided.
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Quadriceps setting (quad sets) in pain-free positions. Have the patient set the quads with the knee in various positions while focusing on developing tension in the VMO. Because the site of irritation varies among patients with PF dysfunction, identify pain-free positions to ensure nondestructive loading.67,96
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Quad sets with straight-leg raise. Have the patient perform straight-leg raising (SLR) exercises in supine or long-sitting positions to target quadriceps control. Because many fibers of the VMO originate on the adductor tendons and medial intramuscular septum, it was suggested a number of years ago that simultaneous activation of the hip adductors during contraction of the quadriceps might provide a firm base for the VMO.34 As a result, some exercise programs for treatment of PFPS6,61,166 have recommended combining SLR exercises with isometric hip adduction or external rotation of the femur (so that the adductors contract during the SLR exercises). However, a study using electromyography (EMG) demonstrated that SLR exercises performed in the supine position with simultaneous external rotation of the femur or resisted isometric hip adduction were no more effective in activating the VMO relative to the VL than SLR exercises performed with the femur in neutral rotation.130
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Progression of resisted isometrics. Initiate multiple-angle isometrics against resistance to knee extension in pain-free positions as tolerated by the patient. During resisted isometrics of the knee extensors, have the patient simultaneously resist medial rotation of the tibia to optimize activation of the VMO.142
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FOCUS ON EVIDENCE
Because the lower fibers of the VMO attach to the anteromedial aspect of the proximal tibia via the medial extensor aponeurosis, it is thought that the fibers may resist lateral tibial rotation during resisted knee extension. LaPrade and colleagues142 carried out a study to determine if active medial rotation of the tibia led to preferential recruitment of the VMO over the VL. Investigators also sought to further explore the effect of hip adduction during resisted knee extension.
Study participants with and without PFPS performed five different isometric knee extension exercises in various combinations of hip adduction and medial rotation of the tibia while in a sitting position with the knee flexed. Results of the study showed no significant differences in VMO/VL ratios between the PFPS group and the controls during any of the exercise conditions. Results also demonstrated that the VMO/VL ratio was highest when there was simultaneous resistance to knee extension and medial tibial rotation (initiated in 30° of lateral tibial rotation). However, the ratio was not significantly higher than when resisted knee extension alone was performed. During simultaneous resisted hip adduction and knee extension, VMO and VL recruitment was almost equivalent, indicating no preferential activation of the VMO, and VMO activation also was less than with resisted knee extension alone. This study did not evaluate the effects of exercise on pain or improved function.
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Short-arc terminal extension. Begin with the patient supine and knee flexed around 20° (see Fig. 21.23). If tolerated and the motion is not painful, apply light resistance at the ankle. Strengthening in terminal extension trains the muscle to function where it is least efficient because of its shortened position and where there is minimal patellar compression because it is superior to the femoral groove. End-range knee extension is needed when lifting the leg into bed and moving the covers, as well as when lifting the leg into a car.
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PRECAUTION: If there is irritation of the synovial lining of the suprapatellar pouch or bursa, terminal knee extension may be painful and should be avoided until the pain subsides.
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Weight-Bearing (Closed-Chain) Exercises
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A progression of closed-chain/axial-loading exercises, typically performed in weight-bearing positions, should be a major component of an exercise program for PFPS to reduce PF symptoms, increase muscle performance and dynamic control of knee, hip, and trunk, and to improve neuromuscular control/response time and balance.25,110,161,195,290 As discussed previously, if excessive valgus alignment of the knee occurs during weight-bearing activities involving knee flexion (squats, lunges, stair ascent or descent, or landing from a jump), it may be indicative of weakness of hip abductors, extensors, and/or external rotators. Strengthening these muscle groups in weight-bearing positions and practicing movement strategies in proper alignment should be a priority.110,161,227,228,290
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PRECAUTION: Because there are higher patellar compressive loads when the knee is flexed beyond 60° during weight bearing, exercises and activities with the knee flexed beyond this angle may provoke symptoms. Use caution when the patient is ready to progress beyond 60°. Have the patient carefully monitor symptoms and stop the exercise if symptoms develop.
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CLINICAL TIP
When selecting weight-bearing exercises for patients with PFPS, it is important to know that some activate the VMO to a greater extent than others. An EMG study9 of five weight-bearing exercises in single-leg stance demonstrated the following from greatest to least VMO recruitment: wall squat (wall slide), forward step-up, minisquat, reverse step-up, and lateral step-up. (Refer to the last section of this chapter and Chapter 23 for detailed descriptions of various weight-bearing exercises.)
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If full weight bearing is painful, begin with partial weight-bearing exercises. Progress exercises in standing as tolerated.
To improve strength and muscular endurance, have the patient perform multiple repetitions of appropriate exercises until PF symptoms or loss of control just begins to occur. Do not push beyond that point in order to avoid faulty mechanics or loss of control.
Initiate terminal knee extension against light resistance in standing for end-range knee control (see Fig. 21.26).
Introduce bilateral progressing to unilateral minisquats, which may be useful for improving patellar tracking, early in the exercise program when weight bearing and partial squatting are tolerated and do not provoke symptoms (see Fig. 21.27). Be sure that the knees remain aligned over the toes during squatting.
Progress dynamic exercises by adding double-leg, then single-leg standing wall slides, short-step, then long-step lunges, and forward, backward, and lateral step-ups and step-downs to the exercise program. Add elastic resistance for further challenge.
+
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NOTE: Based on a study of adults without PFPS, there is some evidence to suggest that the VMO/VL ratio is higher during single-leg minisquats than a maximum voluntary isometric quadriceps contractions performed in a standing position.116
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Select resistance equipment for progressive strengthening and muscular endurance training that incorporates weight bearing, such as the seated leg press, the Total Gym® unit, and the stepping machine.
Combine balance and agility training with strengthening exercises in weight-bearing positions.
Include plyometric training for individuals wishing to return to high-demand activities if symptoms do not recur (see Chapter 23).
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CLINICAL TIP
When using a seated leg press to strengthen the hip and knee extensors, combining isometric hip adduction with resisted extension provides no additional benefit compared with performing the exercise with the hips in neutral in the frontal plane.269
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Functional Activities
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Practice simulated functional activities and activity-specific drills without provoking symptoms to prepare the patient to return to the desired activities (see Chapter 23). If abnormal lower extremity alignment occurs during weight-bearing activities despite improvements in muscle strength and endurance, integrate movement reeducation into activity-specific drills to reinforce proper movement strategies.
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Modify Biomechanical Stresses
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Assess lower extremity mechanics, and modify any faulty alignment. If the patient exhibits excessive foot pronation, a foot orthosis, such as a medial wedge, may reduce the stresses at the knee and decrease PF pain.65,100 However, in adults without PFPS, use of a either a medial or lateral wedge or no wedge has been shown to have no significant impact on activation of the VMO and VL muscles during a single-leg minisquat and a maximum isometric contraction of the quadriceps in a standing position.116
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Outcomes
Two systematic reviews of the literature focusing on quality randomized, controlled studies for PFPS have revealed that interventions most effective for reducing pain and improving function were quadriceps strengthening, acupuncture, and combinations of interventions that include quadriceps strengthening with patellar taping and use of biofeedback.22,49 The effectiveness of a patellar brace was neither refuted nor supported, nor was the use of manual therapy techniques, such as stretching and manipulation. A more recent evaluation of the scope and quality of systematic reviews on the effectiveness of treatment of PFPS also supported the findings of the earlier reviews.13
No particular exercise approach has been found to be superior to another for reducing symptoms and improving function. Consequently, there is ongoing debate as to whether nonweight-bearing or weight-bearing exercises yield better outcomes. Herrington and Al-Sherhi110 conducted a study on the effects of nonweight-bearing versus weight-bearing exercises in a group of male participants with patellofemoral pain. Participants were randomly assigned to one of three groups: nonweight-bearing resisted knee extension exercise, weight-bearing resisted knee extension exercise, or no exercise (controls). All participants were instructed to avoid pain-provoking activities during the course of the study. The two exercise groups carried out their programs three times per week for 6 weeks. At the conclusion of the study the two exercise groups showed a significant reduction in pain and improvement in overall function and strength of the knee extensors. However, there were no significant differences between the two exercise groups following the treatment program, indicating that both forms of resistance exercise were equally effective. It should be noted that the control group exhibited a decrease in overall function and no change in pain or knee extension strength throughout the course of the study.
Although there is a substantial body of evidence indicating that decreased strength and flexibility of regions proximal to the knee are associated with PFPS, only a few studies, to date, have evaluated the effectiveness of a treatment program that targets the hip, pelvis, and trunk. Several of these studies evaluated the effect of hip strengthening,25,161,195 whereas others evaluated the effects of a combined program of strengthening hip musculature and stretching the IT band and hip flexors290 or stretching the hamstrings, IT band, and plantarflexors.85
A summary of two case studies161 indicated that, after a 14-week program of strength and endurance training of hip, pelvis, and trunk musculature, both patients reported a decrease in pain and exhibited increased hip extensor and abductor strength and improvements in functional abilities. Motion analysis of one patient following treatment showed 12° and 5° decreases respectively of hip internal rotation and adduction of the stance leg during a step-down task.
More recently, Nakagawa and colleagues195 conducted a randomized, controlled pilot study with 14 patients with PFPS to investigate the effectiveness of a quadriceps strengthening program with and without the addition of strengthening exercises for the hip abductors and external rotators. A home exercise program was carried out five times per week for 6 weeks. Pain, isokinetic eccentric torque of the quadriceps and hip abductors and external rotators, and EMG analysis of the gluteus medius activation were measured before and after the treatment program. A decrease in pain during dynamic functional activities and increased activation of gluteus medius during a maximum voluntary isometric contraction occurred only in the treatment group (the group that performed the hip strengthening exercises). Eccentric knee extensor torque increased in both groups, but there was no significant difference in eccentric hip muscle torque in either group before or after the exercise program.
Fukuda85 conducted a randomized, controlled study of 70 sedentary females with anterior knee pain: 22 received knee exercises that emphasized stretching and strengthening the knee musculature, 23 received the same program with the addition of hip strengthening and stretching, and 25 served as controls and did not receive any treatment. Interventions were three times per week for 4 weeks in the clinic only. Measures included a lower extremity functional scale, an anterior knee pain scale, and the single-limb single hop test. All groups were the same at baseline. After intervention both exercise groups showed significant improvement in function and reduced pain compared to the controls. The group that performed the combined hip and knee exercise program showed greater improvement in all measures (compared to the knee exercise group), although the measures were not statistically significant except for the reduction in pain during stair descent.
Systematic reviews and preliminary studies, such as those described in this discussion of outcomes, provide some insight into the effectiveness of various exercises for management of PFPS. However, more rigorously designed studies must be carried out to enable therapists to gear interventions to maximize each patient's outcomes.
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Patellar Instability: Surgical and Postoperative Management
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Following conservative (nonoperative) management of a primary (first-time) patellar dislocation, the rate of recurrence is between 15% to 44% and is as much as 50% after subsequent episodes.47 When nonoperative interventions fail in the management of patellar instability, including acute and recurrent dislocation or chronic subluxation and associated pain, crepitus, or degeneration of the articular surfaces of the PF joint, surgery usually is indicated.
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Surgical interventions can be used to alter the alignment of the patella, correct imbalances of the static stabilizers (see Fig. 21.4) of the patella and knee, decrease an abnormal Q-angle (see Fig. 21.3 for depiction of Q-angle measurement), improve tracking of the patella, and débride or repair articular surfaces of the PF joint. However, before a surgical procedure is selected, the etiology of symptoms and identification of factors contributing to patellar instability must be determined by a thorough physical examination and radiographic and arthroscopic evaluation.
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Overview of Surgical Options
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Types of surgical options for lateral patellar instability are noted in Box 21.6.40,46,47,86,87,88,89,114,178,179,194,216,226,233 Numerous variations of operative procedures fall under each of these categories. Some are arthroscopic procedures, whereas others involve an open approach. Often a combination of procedures is necessary.
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When soft tissue abnormalities contribute to lateral patellar instability, a proximal realignment procedure, such as repair or reconstruction of the MPFL or VMO imbrication, is often selected. A distal realignment procedure that involves a tibial tubercle osteotomy with patellar tendon transfer is selected when an osseous abnormality is the underlying cause of patellar instability. Repair of chondral lesions associated with acute or recurrent patellar dislocation or trauma may also be necessary.179 In contrast, TKA or patellectomy (a salvage procedure) is performed only for end-stage PF arthritis and collapse of the joint space.87,179,216
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BOX 21.6 Surgical Options for Management of Lateral Patellar Instability and Associated Structural Impairments Soft Tissue and Osseous Procedures for Patellar Instability
Medial patellofemoral ligament repair or reconstruction with autograft or allograft
Medial retinacular imbrication (advancement)
Lateral retinacular release, including release of the lateral patellofemoral and patellotibial ligaments
Imbrication and medialization of the VMO
Distal realignment of the extensor mechanism (anteromedialization of the tibial tubercle and insertion of the patellar tendon)
Trochleoplasty (to improve the size/shape of the trochlear groove) for trochlear dysplasia
Articular Cartilage Procedures Arthroscopic débridement
Repair of patellofemoral articular cartilage lesions (microfracture, osteochondral autograft transfer/mosaicplasty, autologous chondrocyte implantation)
Abrasion arthroplasty/chondroplasty of the posterior surface of the patella (used less frequently with the advent of surgeries to repair articular cartilage)
Procedures for End-Stage Patellofemoral Arthritis
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The two broad categories of surgery for patellofemoral instability—proximal and distal realignment of the extensor mechanism—may be performed with or without a lateral retinacular release (LRR). As an independent procedure, LRR has been shown to be useful for alleviating or reducing patellofemoral pain if the cause of the pain stems from compression of lateral structures of the knee (lateral compression syndrome) as the result of an excessive lateral tilt of the patella (without subluxation) but not for management of lateral patellar instability.47,79,87,179,226
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FOCUS ON EVIDENCE
The results of several current literature reviews46,47,233 have demonstrated that the use of LRR in isolation for recurrent or acute lateral patellar instability yields poor long-term outcomes (high recurrence rates for dislocation). According to another review,87 LRR failed to realign the patella more medially. All reviews concluded that LRR in isolation is not effective for treatment of lateral patellar instability.
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Operative procedures, other than proximal or distal extensor mechanism realignment, sometimes are used for recurrent patellar instability. Trochleoplasty, which involves deepening of the trochlear sulcus, may be indicated if trochlear dysplasia is contributing to patellar instability.47 If excessive rotational deformity of the lower extremity is determined to be an underlying cause of severe patellar malalignment and recurrent instability, a recently reported procedure—supratubercle, derotational, high tibial osteotomy—may be indicated as an alternative to proximal or distal realignment procedures.219
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After either proximal or distal extensor mechanism realignment, a number of factors influence the rate of progression of rehabilitation. They include the type of surgical procedure performed; the patient's age, general health, and severity of patellofemoral symptoms prior to surgery; the presence of other pathologies; the desired functional outcomes; and the patient's adherence to the prescribed home exercise program and motivation to return to functional activities.
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Proximal Extensor Mechanism Realignment: Medial Patellofemoral Ligament Repair or Reconstruction and Related Procedures
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Repair, realignment, or reconstruction of the static and dynamic medial patellar support structures, such as the MPFL, are surgical options performed with or without LRR for the patient with recurrent lateral patellar instability (dislocation or subluxation) and associated pain and compromised function despite a course of nonoperative treatment.4,40,47,196 MPFL repair or reconstruction also may be used following an acute, first-time lateral patellar dislocation as the result of trauma. Other proximal realignment procedures include VMO imbrication (advancement) and medial retinacular reefing/tightening. These soft tissue procedures are also appropriate for the skeletally immature patient with patellar instability or may be used in conjunction with distal realignment of the extensor mechanism involving an osteotomy in the skeletally mature patient.87,114
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Indications for Surgery
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Although opinion varies, the following are often cited as indications for MPFL repair or reconstruction or other proximal realignment procedures with or without LRR.4,40,47,87,88,114,194,196,216,226
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Deficiency (acute tear, chronic laxity) of the medial patellar support structures, in particular the MPFL, a primary static stabilizer, leading to malalignment and recurrent instability of the patella
Excessive (or abnormal) lateral tracking of the patella and insufficiency of the VMO, a primary dynamic medial stabilizer of the patella
Normal boney architecture (normal tibial tubercle-trochlear groove distance) and no evidence of patella alta trochlear dysplasia
Painful, lateral compressive forces at the patellofemoral joint and persistent lateral tilt of the patella despite a previous LRR
An appropriate realignment option for the skeletally immature patient with patellar instability114
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CONTRAINDICATIONS: Proximal realignment procedures are not appropriate for patients with articular degeneration of the medial patella, patella alta, or trochlear dysplasia, because they may exacerbate or have no impact on symptoms.87,114
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Background and Operative Overview
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Proximal realignment procedures use an open surgical approach through a medial parapatellar incision preceded by an arthroscopic examination of the knee, LRR, débridement of any loose osteochondral fragments or partial-thickness lesions, and, if necessary, microfracture for full-thickness chondral lesions.179
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MPFL repair or tightening. An acute lateral patellar dislocation usually results in disruption of the MPFL and is managed with a direct repair.40,114 Repair is also an option if the ligament is lax as the result of recurrent dislocations. To expose the MPFL, the medial retinaculum must be opened. Depending on the location(s) of the tear, the ligament is reattached to the femoral condyle or patella or to both boney surfaces with suture anchors, or the ligament fragments are repaired with nonabsorbable locking sutures in a pants-over-vest fashion.
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MPFL reconstruction. This procedure, which has many variations, is used if the MPFL is incompetent as the result of recurrent lateral dislocation or subluxation or if a previous repair or reefing of the ligament has failed. Reconstruction involves reinforcement of the MPFL with an autogenous hamstring, TFL, or quadriceps tendon graft or allograft.4,62,196
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Depending on the type of reconstruction and graft selected, the patellar and femoral ends of the graft are secured in drill holes with sutures, suture anchors, or screw fixation. In other procedures drill holes are not required, therefore eliminating the risk of patellar fracture.
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VMO imbrication (advancement). This procedure is performed to improve the resting length-tension relationship of the VMO by moving the muscle to a more central and distal location.87,194,216,226
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Lateral retinacular release and other concomitant procedures. If a lateral patellar tilt is identified, LRR is indicated to reduce the tilt and restore the balance of the patella in the trochlea.46,87,226,233 LRR is performed arthroscopically through several lateral parapatellar portals. The procedure "releases" the lateral structures supporting the patellofemoral joint, specifically the superficial and deep portions of the lateral retinaculum and the lateral patellofemoral and patellotibial ligaments by means of an incision extending from the superior lateral pole of the patella to just lateral and inferior to the patellar tendon.179 The location of the incision is such that the superior lateral and inferior lateral geniculate arteries are cut and must be cauterized immediately and tied. However, the release leaves the tendinous portion of the VL muscle intact so as not to compromise the function of the quadriceps. Electrocautery194 and, most recently, radiofrequency ablation89 are alternatives to surgically incising the retinaculum. The advantages of these methods for releasing the lateral structures are less bleeding and subsequent hemarthrosis.
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In addition to repair or reconstruction of the MPFL, sometimes the medial patellotibial and medial patellomeniscal ligaments must be tightened or repaired.87,88 A boney distal realignment procedure also may be combined with a medial soft tissue repair or reconstruction.87,88,194
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Postoperative complications that can occur with any of the patellofemoral surgeries include a superficial infection, but rarely an intra-articular infection, or a DVT. Patellar adhesions and arthrofibrosis can compromise postoperative ROM.
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In rare instances, complex regional pain syndrome can develop (see Chapter 13).48 There are also complications seen in proximal realignment procedures and LRR.87,156
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Following proximal realignment. Overtightening medial soft tissue structures or "overtensioning" the native MPFL or graft tissue during repair or reconstruction, inaccurate graft placement, and/or excessive imbrication of the VMO can exacerbate pain and increase loads on medial articular surfaces, leading to deterioration.4,40,47 Significant scarring or over-tightening of medial tissues also can cause increased patellar rotation and excessive medial tracking leading to retropatellar erosion or increased risk of medial instability of the patella.40,87 In contrast, inadequate medial tightening or VMO realignment may result in no change in patellar position, tracking, or a patient's symptoms. Although the risk of patellar fracture is low, it is a complication that can occur during MPFL reconstruction procedures that require patellar drill holes for graft placement and fixation.47
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Entrapment, irritation, or a neuroma of the saphenous nerve as it passes the adductor tubercle and splits at the pes anserine tendon can occur with any procedure involving structures on the medial side of the knee.87
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Following LRR. Several complications may occur with LRR.22,89,156 Because of the location of the geniculate artery, hemarthrosis can occur if it is not adequately cauterized during surgery. Thermal injury to overlying skin can occur with radiofrequency ablation or electrocautery.89 Another complication, postoperative medial patellar subluxation, can develop as the result of the lateral release extending too far proximally, causing weakness of the VL muscle. In rare instances following VMO advancement, rupture of the quadriceps tendon occurs.
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Postoperative Management
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Postoperative rehabilitation after MPFL repair or reconstruction or other proximal realignment procedures follows a course summarized in Table 21.4.4,40,88,156,196 The patient is progressed through each phase of rehabilitation based on signs and symptoms and the attainment of phase-specific goals.204
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Immobilization and Weight-Bearing Considerations
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A compression dressing is applied following surgery, and the knee is immobilized in a range-limiting, hinged orthosis locked in extension or in a posterior splint to prevent excessive knee flexion and protect the repaired or reconstructed soft tissues. Some surgeons allow removal of the immobilizer for early ROM in a protected range or while wearing the range-limiting orthosis within a few days after surgery,4,40,156,196 whereas others advocate continuous immobilization for a week postoperatively.114,226
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During ambulation with crutches in the early postoperative period, the knee orthosis is locked in extension. From 25% weight bearing to weight bearing as tolerated is permitted on the operated extremity. Full weight bearing with the immobilizer locked is permitted by about 4 weeks after surgery.196 Full weight bearing with the orthosis unlocked and without an assistive device is permitted only when the patient can control the knee and has achieved full, pain-free passive and active knee extension (no evidence of an extensor lag/quadriceps lag).156,226
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Exercise goals following MPFL repair or reconstruction or VMO imbrication are directed toward restoring and improving the function of the entire lower extremity and trunk, not just the knee.79,156,161,228 As with nonoperative management of patellofemoral dysfunction, many of the exercises traditionally selected for a patient's rehabilitation have focused on regaining pain-free knee ROM, maintaining patellar mobility, and recruiting the quadriceps mechanism as a unit and the VMO in particular. These interventions are designed to prevent or remediate patellar restrictions and an extensor lag.61,130,156,274,283
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A more recent but equally important postoperative focus for exercise interventions is remediating strength deficits in the trunk, pelvis, and hip abductor, external rotator, and extensor muscles and improving flexibility of the hip and ankle musculature.121,161,224,227,228
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Exercise goals, a progression of exercise interventions, and criteria to progress from one phase of rehabilitation to the next after MPFL repair or reconstruction or other proximal realignment procedures are summarized in the following sections.88,156,196 Exercise precautions after proximal and distal extensor realignment procedures are noted in Box 21.7.114,156,196
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BOX 21.7 Exercise Precautions After Proximal or Distal Realignment of the Extensor Mechanism
Initiate PROM or A-AROM→AROM exercises in a hinged, range-limiting orthosis to prevent excessive knee flexion or a valgus stress to the knee.
Progress knee flexion gradually so as not to disrupt sutures after MPFL repair or reconstruction, advancement of the VMO, or tibial tubercle osteotomy with medial transfer of the patellar tendon.
When assisting with supine-lying hip and knee flexion/extension ROM, stand on the contralateral side of the operated extremity to avoid placing a valgus stress on the knee and stretching repaired medial structures.
Perform SLR on the operated side with the orthosis locked in extension.
Begin weight-bearing exercises, such as weight shifting, in bilateral stance with the knee orthosis locked in extension.
Begin bilateral closed-chain exercises, such as minisquats, in the unlocked, range-limiting knee orthosis when 50% weight bearing on the operated side is permissible.
Continue to keep the orthosis locked in extension during closed-chain exercises or ambulation in full weight bearing until quadriceps control has been established (full, active knee extension/no extensor lag).
Postpone unilateral weight-bearing exercises that involve full weight on the operated side and without the orthosis:
Do not perform a maximum voluntary contraction (MVC) of the quadriceps for at least 12 weeks after VMO advancement or tibial tubercle osteotomy.
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Exercise: Maximum Protection Phase
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Goals and interventions. During the first 4 weeks after surgery, the repaired or reconstructed medial patellar tissues are in the acute and subacute stages of healing and vulnerable to excessive stresses. The goals and interventions during this period are directed toward achieving independent ambulation with crutches; controlling pain and swelling; preventing complications, such as a DVT or adhesions; and beginning to regain quadriceps control and ROM of the knee while protecting the reconstructed soft tissues (see Table 21.5).
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Achieve independent ambulation. Gait training with crutches for protected weight bearing and knee orthosis locked in extension
Control pain and swelling. Apply cold and compression regularly throughout the day.
Patient education. Review weight-bearing and exercise precautions with the patient to protect the repaired ligament or graft tissue while it is most vulnerable to excessive stresses (see Box 21.7). Establish and teach a home exercise program.
Restore ROM. Perform knee flexion/extension exercises (PROM→A-AROM and AROM) in the range-limiting orthosis within a day or two after surgery. Depending on the type of repair or reconstruction performed, the goal is to attain full passive and active knee extension and at least 90° flexion by the end of week 4.88,156,196 Stretch hip and ankle musculature, if restricted.
Maintain patellar mobility. Apply gentle (grades I and II) patellar mobilization (superior and inferior) to reduce pain and prevent adhesions.
Reestablish neuromuscular control and improve muscle performance. Begin gentle quadriceps setting for knee control and active superior patellar gliding with emphasis on VMO activation augmented with pain-free neuromuscular electrical muscle stimulation or biofeedback. While wearing the orthosis locked in extension, initiate SLRs in supine, prone, and side-lying positions for hip control. With the orthosis unlocked, begin partial-range heel-slides in the supine position and bilateral minisquats and heel raises when 50% pain-free weight bearing on the operated side is possible.
Criteria to progress. Criteria to progress to the intermediate phase of rehabilitation include156,196:
Minimal pain and swelling.
Incision healing well; no signs of infection.
Full, active knee extension (no evidence of extensor lag) and at least 90° of knee flexion.
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Exercise: Moderate Protection/Controlled Motion Phase
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Goals and interventions. During the intermediate phase of rehabilitation (from approximately 4 to 8 weeks postoperatively), soft tissues are in the repair and remodeling stage of healing. Full weight bearing without an assistive device but with the orthosis locked typically is permitted by 4 to 6 weeks after surgery. The patient should be able to achieve functional knee ROM by the end of this phase of rehabilitation.
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As symptoms subside and quadriceps strength improves, the focus of this phase of rehabilitation is to establish a normal gait pattern with the orthosis unlocked, continue to increase knee ROM, and increase flexibility of hip and ankle structures if restricted. It is equally important to develop strength and endurance of hip and trunk musculature, improve neuromuscular control/response time and balance, regain cardiopulmonary endurance, and progress and reinforce the home exercise program.
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Normalize the gait pattern. If full weight bearing is pain-free and quadriceps control is sufficient (no extensor lag), practice walking with crutches or a cane with the orthosis unlocked.
Restore ROM and joint mobility. Begin low-intensity, prolonged stretching and grade III joint mobilization to increase ROM of restricted areas. Achieve 0° to 120° knee ROM by the end of week 6 and 0° to 135° by the end of week 8.4,88,156 Also stretch tight musculature. Specifically evaluate the gastrocnemius, soleus, hamstring muscles, and IT band, because they have been shown to be tight in patients with PF dysfunction.224
Improve muscle performance. Progress pain-free, closed-chain (bilateral minisquats, seated leg press) and open-chain resistance training to increase strength and muscular endurance of the entire lower extremity. Place emphasis on strengthening the knee extensors and hip extensors, abductors, and external rotators. (Suggestions for a progression of nonweight-bearing and weight-bearing exercises are noted in the previous section on nonoperative management and described in the final section of this chapter and Chapter 20).
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PRECAUTION: Be certain to have the patient perform resisted exercises only in pain-free ranges and in positions consistent with weight-bearing precautions. During weight-bearing exercises, reinforce proper lower extremity alignment to avoid knee valgus during flexion.
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Improve neuromuscular control and response time, proprioception, and balance. While wearing the orthosis locked in extension, begin neuromuscular/proprioceptive training and stabilization and balance activities on a stable surface and then on unstable surfaces (minitrampoline, BOSU®, or wobble board). Place emphasis on maintaining proper lower extremity alignment. Progress from bilateral to unilateral stance and from uniplanar to multiplanar movements. As knee control improves, unlock the orthosis during training.
Improve cardiopulmonary endurance. Begin a stationary cycling program while wearing the range-limiting orthosis. Begin with a high seat adjustment and low tension. If wound healing is adequate, begin pool walking and marching or jogging in a pool.
Criteria to progress. The following criteria should be achieved to advance to the final phase of rehabilitation.156
No swelling or extensor lag
Knee ROM: 0° to 135°
Sufficient strength of knee and hip musculature (at least 75% compared to nonoperated side) to initiate lower extremity functional activities
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Exercise: Minimum Protection/Return to Function Phase
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Goals and interventions. During the final phase of rehabilitation, which extends from 8 to 12 weeks and beyond, the patient gradually participates in more demanding functional activities without recurrence of pain, patellar instability, or joint effusion. By 12 weeks postoperatively, the patient should be able to begin land-based jogging and, by 16 to 20 weeks, return to a full level of activity without symptoms. Modification of some activities, however, may be necessary.4
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Emphasize activity-specific training, always maintaining proper lower extremity alignment. Efforts should be made to modify the patient's lifestyle to avoid symptom-provoking activities, at least on a temporary basis. Develop and implement a self-managed program to continue to improve and maintain strength, flexibility, and balance, and devise a plan for adherence.
+
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NOTE: Continued use of patellar taping or a patellar tracking orthosis during exercise may be useful during the progression of exercises and transition to high-demand functional activities.
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Refer to the exercise progression previously discussed for advanced nonoperative management and selected exercises described in the final sections of this chapter and Chapter 20. More advanced exercises, including plyometric training and agility drills, are described in Chapter 23.
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Outcomes
Outcomes reported after repair or reconstruction of the MPFL (the most common proximal realignment procedures for acute and chronic patellar instability) vary considerably among studies because of the many variations of procedures—some performed in isolation and others combined with lateral release or distal realignment. Following a first-time lateral dislocation, the results of a randomized, controlled trial demonstrated that nonoperative management and repair of medial structures results in similar rates of subsequent patellar dislocation, suggesting there is no advantage of undergoing surgery for an acute (first-time) dislocation prior to a course of nonoperative exercises.214
Camp and colleagues40 carried out a retrospective review of 27 patients (29 knees) who underwent MPFL repair at an average of 19 years of age for recurrent patellar instability. The success rate for the prevention of recurrence of patellar dislocation for an average of 4 years following MPFL repair was 72% (21 of 29 knees), which the investigators considered a relatively high rate of recurrence. The patients who reported a postoperative dislocation subsequently underwent additional procedures, including MPFL reconstruction and/or distal realignment (tibial tubercle osteotomy).
In contrast, MPFL reconstruction procedures have resulted in high patient satisfaction and low redislocation rates. For example, in a retrospective case series, Drez and co-investigators62 reported the use of MPFL reconstruction with a soft tissue graft (and no distal realignment) in 15 patients with recurrent lateral instability after first-time patellar dislocation. At a mean follow-up of 31.5 months (minimum of 2 years), 93% of patients had excellent results (10 patients) or good results (3 patients) on an objective functional outcome and patient satisfaction scale. Only one of the 15 patients reported one episode of subluxation during the follow-up period.
There is general agreement that LRR performed in isolation is not an effective procedure for management of acute or chronic patellar instability.46,47,226,233 The poor results can be attributed to the inability of LRR to align the patella in a more medial position.87
Poor outcomes, overall, following the many proximal realignment procedures described in the literature appear to be due more to retropatellar pain than to recurrent instability.114 Patients with generalized joint hypomobility or uncorrected trochlear dysplasia tend to have a high rate of redislocation and typically require a distal realignment procedure.88
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Distal Realignment Procedures: Patellar Tendon with Tibial Tubercle Transfer and Related Procedures
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For a patient with recurrent subluxation/dislocation of the patella with or without degeneration of the lateral and distal articular surfaces of the patella, a procedure involving distal realignment of the extensor mechanism may be the surgical intervention of choice. A medial transfer and possibly anteriorization of the tibial tubercle decreases laterally directed forces on the patella to improve patellar tracking and shifts contact stresses in a medial and proximal direction away from chondral lesions of the distal and lateral articular surface of the patella.47,86
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Distal realignment procedures may be used in isolation or coupled with LRR or a proximal soft tissue procedure, such as MPFL repair or reconstruction or medial capsular reefing.47, 88,194
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Indications for Surgery
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The following are indications for distal realignment procedures.47,86,87,179,194,216,226
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Recurrent episodes of lateral patellar instability (dislocation/subluxation) and a sense of the knee "giving way" because of patellar malalignment due to lateralization of the tibial tubercle and patellar tendon insertion
Painful lateral tracking of the patella with no instability
Anterior knee pain associated with patellar maltracking and patellofemoral arthrosis (chondral or osteochondral defects) of the lateral and distal retropatellar surfaces
Abnormally increased Q-angle
Excessive tibial tubercle-trochlear groove distance (> 15 mm)
CONTRAINDICATION: Boney procedures are not recommended for the skeletally immature patient whose tibial tubercle growth plate is open. Recurvatum of the knee can develop with premature closure of this epiphyseal plate.86,114
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Background and Operative Overview
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The purpose of distal realignment procedures is to reduce patellar instability and anterior knee pain by reducing laterally directed forces on the patella and improving patellar tracking.47,86,87,216,226 Distal realignment procedures are performed using an open surgical approach. However, arthroscopic examination of the knee joint, débridement of the articular surface of the patella, and sometimes an LRR precede the distal realignment procedure.
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A number of surgical techniques for distal realignment have been reported.
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Tibial tubercle transfer (Elmslie-Trillat procedure). An osteotomy of the tibial tubercle is performed; the boney prominence is then transferred medially and secured with screw fixation.47,86,88
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Anteriorization (elevation) of the tibial tubercle. Typically combined with a medial tibial tubercle transfer, this procedure involves displacing the tubercle anteriorly by means of a bone graft.226 This serves to reduce shear forces on the patella and offloads the articular surfaces of the distal patella.47,86,226
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Distal medialization of the patellar tendon. This procedure involves only a soft tissues transfer for the skeletally immature patient.
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Uncommon but serious complications associated with distal realignment procedures include tibial fracture during placement of fixation screws, neurovascular injury during surgery, inadequate skin closure or sloughing over the osteotomy site, soft tissue infection or osteomyelitis, and nonunion of the transposed bone.86,226 Redislocation can occur laterally because of undercorrection or medially with overcorrection, particularly in patients who return to high-demand activities.86,194
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Pain at the anterior tibial tubercle from the fixation screws is not unusual. Therefore, screws are removed routinely 6 to 12 months after surgery.86 As with all patellofemoral surgeries, patellar adhesions can occur, restricting knee motion. Because distal realignment shifts retropatellar loads medially and proximally, excessive medialization of the tibial tubercle and patellar tendon (> 15 mm past the original insertion site) can cause excessive contact pressure on the medial patellar facet and medial compartment, contributing to arthrosis of these areas over time.47
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Postoperative Management
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Immobilization and Weight-bearing Considerations
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Depending on the type of fixation used, rehabilitation after distal realignment involving boney procedures must progress even more gradually than rehabilitation following proximal realignment of soft tissues to allow time for boney healing. Ambulation with crutches while wearing a knee orthosis locked in extension is permissible the day after surgery. Weight bearing is limited to touch-down/toe-touch for the first 4 weeks or until radiographic verification of bone callus formation at the osteotomy site has occurred.86,156 Weight bearing is progressed gradually, with full weight bearing permissible without the immobilizer at 8 weeks if quadriceps control is sufficient.156
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ROM also is progressed more gradually than after soft tissue procedures. (Refer to exercise precautions noted in Box 21.7.) A range-limiting orthosis is worn that allows motion from only 0° to 30°156 or 0° to 60°88 of flexion during the first week to 90° of flexion by the end of week 4 to 135° by the end of week 8.156 Closed-chain exercises are initiated in the range-limiting knee orthosis as increased weight bearing is permitted. Otherwise, exercises are similar to those for nonoperative management, LRR, and proximal realignment procedures. The return to full activity generally takes about 5 to 6 months and is based on bone healing and lower extremity strength.
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Outcomes
Successful outcomes after distal realignment surgeries for recurrent patellar instability and/or painful patellar maltracking without instability, often associated with chondral lesions, are contingent on correctly determining the underlying causes of the patient's symptoms. Patients without degeneration of the retropatellar surface or those with lateral and distal lesions tend to have better results than those with medial articular lesions or advanced PF arthritis.47,179
Outcomes following medial tibial tubercle transfer have been shown to be better for patients with painful lateral tracking of the patella but no patellar instability than for patients with at least a 1-year history of recurrent instability.136 However, the investigators advocated tibial tubercle transfer for painful maltracking and recurrent instability because improvement occurred in both groups of patients.
Often distal realignment procedures are coupled with a proximal repair and/or lateral release to correct malalignment and relieve symptoms. Results of studies of combined procedures reflect good to excellent outcomes for most patients measured by one or more objective assessment tools. For example, Garth and colleagues88 studied a group of young adults (mean age, 18 years) with recurrent patellar instability despite a course of conservative management after sustaining an acute, traumatic, lateral dislocation of the patella. After undergoing distal realignment coupled with MPFL repair and advancement of the patellomeniscal ligament, 90% (18 of 20) patients reported good to excellent results in knee function and patient satisfaction and no recurrence of instability at a minimum follow-up of 24 months. The results of another study194 in which three procedures were performed (lateral release, repair of medial supporting structures, and distal realignment) revealed that 32 of 42 knees (76%) in 37 patients had good or excellent outcomes at follow-up (mean, 44 months; minimum, 25 months; range, 25 to 85 months). At the time of follow-up, redislocation had occurred in four knees (9.5%).
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Ligament Injuries: Nonoperative Management
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Ligament injuries occur most frequently in individuals between 20 and 40 years of age as the result of sport injuries (e.g., skiing, soccer, football) but can occur in individuals of all ages. The anterior cruciate ligament (ACL) is the most commonly injured ligament. Often, more than one ligament is damaged as the result of a single injury. Sprain and strain injuries of the knee are classified as knee instability and movement coordination impairments.149
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Anterior Cruciate Ligament
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ACL injuries can occur from both contact and noncontact mechanisms (Fig. 21.12). The most common contact mechanism is a blow to the lateral side of the knee resulting in a valgus force to the knee. This mechanism can result in injury not only to the ACL but also to the medial collateral ligament (MCL) and the medial meniscus. This injury is termed the "unholy triad" or "terrible triad" injury because of the frequency with which these three structures are injured from a common blow (Fig. 21.13).
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The most common noncontact mechanism is a rotational mechanism in which the tibia is externally rotated on the planted foot. Literature supports that this mechanism can account for as many as 78% of all ACL injuries.202 The second most common noncontact mechanism is forceful hyperextension of the knee.
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With prolonged ambulation on a knee that has a deficient ACL, the secondary restraints (lateral collateral ligament and posterolateral joint capsule) are stressed and become lax and a "quadriceps avoidance gait" may develop.111 The quadriceps avoidance gait in ACL-deficient knees was originally documented and described by Berchuck and colleagues15 as a reduction in the magnitude of the flexion moment about the knee during the limb loading phase of gait due to the patient's effort to reduce contraction of the quadriceps.
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Posterior Cruciate Ligament
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Injury to the posterior cruciate ligament (PCL) (Fig. 21.14) most commonly occurs as the result of a forceful blow to the anterior tibia while the knee is flexed, such as a blow to the dashboard or falling onto a flexed knee. A study by Schulz247 evaluating 587 acute and chronic PCL-deficient knees reported that the three most common mechanisms of injury were a "dashboard"/anterior injury mechanism (38.5%), followed by a fall on the flexed knee with the foot in plantarflexion (24.6%), and lastly, a sudden, violent hyperflexion of the knee joint (11.9%).
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Medial Collateral Ligament
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Isolated injuries to the MCL can occur from valgus forces being placed across the medial joint line of the knee. Whereas most injuries to the ACL and PCL are complete tears of the ligament, injuries to the MCL can be partial or incomplete and are graded utilizing a I, II, III grading classification of ligament injuries described in Chapter 10 (see Fig. 21.13).
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Lateral Collateral Ligament
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Injuries to the lateral collateral ligament (LCL) are infrequent and are usually the result of a traumatic varus force across the knee. It is not uncommon that more than one ligament or joint capsule and sometimes the menisci are damaged as the result of a single injury creating posterolateral instability.
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Ligament Injuries in the Female Athlete
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With an increase in the number of female athletes since the passage of Title IX in 1972, a concurrent increase in the number of injuries to female athletes has been seen, most significantly an increase in the number of knee injuries. Interestingly, when injury to the ACL is sustained in a noncontact manner, a woman is three times more likely to tear the ACL than a man is.7 With the increased number of noncontact ACL injuries in female athletes being reported, the American Academy of Orthopaedic Surgeons published a consensus paper examining the risk factors and prevention strategies of noncontact ACL injuries.98 In addition, clinicians and scientists interested in ACL-injury gender bias have met in retreat three times, the most recent in 2006, to present research, develop a consensus statement, and suggest future investigations on gender bias in ACL injuries.53
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Risk factors identified in these consensus papers fall into four major categories: biomechanical, neuromuscular, structural, and hormonal, and they are summarized here.53,98
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Biomechanical risk factors include the effect of the total chain (trunk, hip, knee, and ankle) on ACL injuries, including awkward or improper dynamic body movements, deceleration, and change of direction. For example, increased hip adduction is related to increased knee valgus, which is associated with ACL injury risk in the female. Also, decreased hip flexion angles and knee flexion has been demonstrated during cutting activities in the female athlete.
Neuromuscular risk factors have an influence on biomechanical factors in that neuromuscular control influences joint position and movement. Valgus collapse at the knee and decreased use of the hip extensors has been reported to be more common in women than in men who have sustained an ACL injury. It has been suggested that this is related to increased anterior shear of the tibia and strain of the ACL during loading (hip-knee flexion when landing following a jump).227 Not only are females weaker in hip and knee strength compared to males (normalized to body weight), but muscle timing and activation patterns of the quadriceps, hamstrings, and gastrocnemius muscles also differ between males and females.
Structural risk factors include femoral notch size, ACL size, and lower extremity alignment. The femoral notch height is smaller and notch angle larger in the male compared to the female, which may affect ACL size. The female ACL is smaller than the male ACL, even when adjusted for body size. The ACL in the female has a lower modulus of elasticity (i.e., less stiff) and a lower failure strength (i.e., fails at a lower load); thus, the joint is more lax than in the male.
Hormonal differences between males and females has also been postulated to be one possible factor related to the increased incidence of female ACL injuries. There are hormone receptor sites for estrogen, progesterone, and testosterone in the ACL of humans. The sex hormones have a time-dependency effect that influences ACL tissue characteristics, such as increasing risk of injury during the preovulatory phase of the menstrual cycle in females.149
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Common Structural and Functional Impairments, Activity Limitations, and Participation Restrictions (Functional Limitations/Disabilities)
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Following trauma, the joint usually does not swell for several hours. If blood vessels are torn, swelling is usually immediate.
If tested when the joint is not swollen, the patient feels pain when the injured ligament is stressed.
If there is a complete tear, instability is detected when the torn ligament is tested.
When effused, motion is restricted, the joint assumes a position of minimum stress (usually flexed 25°), and the quadriceps muscles are inhibited (shut down).272
When acute, the knee cannot bear weight, and the person cannot ambulate without an assistive device.
With a complete tear, there is instability, and the knee may give way during weight bearing, which would prevent the individual from returning to specific work or sport and recreation activities that require dynamic knee stability.
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Ligament Injuries: Nonoperative Management
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Acute sprains, partial ligament tears, and sometimes complete rupture of a single knee ligament can be treated conservatively with rest, joint protection, and exercise. After the acute stage of healing, exercises should be geared toward regaining normal ROM, balance, a normal gait pattern, and strength, endurance, and neuromuscular control of muscles that support and dynamically stabilize the joint during functional activities.64,77,117 The degree of instability following a ligament tear affects the demands the patient can place on the knee when returning to full activity.
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A patient's preinjury activity level and the postinjury level of activity to which he or she expects to return influence the success of a nonoperative treatment program. Relatively sedentary individuals can usually function with some loss of knee stability and can expect to return to preinjury activities following a course of nonoperative management. For select athletes who wish to return to high-demand activities following ACL injury, an intensive rehabilitation program, including balance/perturbation training to stimulate neuromuscular control and develop dynamic knee stability, has been shown to be effective.76,77 In contrast, for patients with extensive ligament damage or concomitant injuries (such as meniscus damage) and poor dynamic knee stability after a period of nonoperative treatment, surgical reconstruction typically is recommended to return to high-level work or sports and a preinjury level of function.
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FOCUS ON EVIDENCE
The descriptive terms "potential coper" and "potential non-coper" have been used in the literature64,77,117,185 to identify and classify those individuals early after ACL injury who are good versus poor candidates for nonoperative rehabilitation based on the results of an initial screening examination. (Potential copers are described as having sufficient dynamic knee stability, the ability to compensate following injury, and good potential to return to preinjury, high-level activities following a course of nonoperative treatment. In contrast, potential noncopers are thought to have poor potential to return to preinjury activities following nonoperative treatment; these individuals typically have poor dynamic knee stability and are advised to consider surgical management.) A study by Moksnes and associates185 evaluated both copers and non-copers after 1 year of intensive rehabilitation. For those not undergoing surgery, 19 of the 27 noncopers (70%) showed excellent knee function and were reclassified as true copers. In the coper group, 15 of 25 (60%) were true copers. (The term "true coper" applies to individuals able to return to preinjury activity level 1 year after ACL injury with no episodes of the knee giving way during activities.)
The results suggest that the prognostic accuracy of the screening examination is poor and therefore support the importance of including all patients with ACL injury in intensive rehabilitation, not just those who initially meet the definition of coper.
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If the collateral or coronary ligaments are involved, because of their superficial location, they may benefit from cross-fiber massage, which helps align the healing fibers and maintain their mobility. Because of the structural characteristics of the MCL (a broad, flat ligament with deep and superficial portions, parallel alignment of collagen fibers, and fan-shaped attachments both proximally and distally), injuries to the MCL are typically managed with a conservative (nonsurgical) approach.301 Conservative management of MCL injuries is described in Table 21.5; progression is based on presenting signs and symptoms.204 A similar rehabilitation program for ACL injuries is followed with appropriate precautions (as noted below) regarding stress to the ligament.
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Nonoperative Management: Maximum Protection Phase
++
Follow the principles described for an acute joint lesion earlier in this chapter.
++
If possible, examine before effusion sets in.
Utilize cold and compression with rest and elevation.
Teach protected weight bearing with use of crutches and partial weight bearing as tolerated.
Teach safe transfer activities to avoid pivoting on the involved extremity.
Initiate quadriceps-setting exercises. The knee may not fully extend for end-range muscle-setting exercises, so begin the exercises in the range most comfortable for the patient. As the swelling decreases, initiate ROM within tolerance.
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Nonoperative Management: Moderate Protection (Controlled Motion) Through Return to Activity Phases
++
As swelling decreases, examine the patient for impairments and functional losses. Initiate joint movement and exercises to improve muscle performance, functional status, and cardiopulmonary conditioning.64,149
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Improve Joint Mobility and Protection
++
Joint mobility. Use supine wall slides (see Fig. 21.19), patellar mobilizations, and stationary cycling; encourage as much movement as possible. Unless there has been an extended period of immobilization, there should be minimal need to stretch contractures.
++
Protective bracing. Bracing may be necessary for weight-bearing activities to decrease stress to the healing ligament or to provide stability when ligament integrity has been compromised. Bracing can be one of two types: (1) range-limiting postoperative type braces that are used to protect healing tissues and then discontinued during later phases of rehabilitation; or (2) functional braces that are used during advanced rehabilitation and also when returning to functional activities. The patient must be advised to modify activities until appropriate stability is obtained.
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Improve Muscle Performance
++
Strength and endurance. Initiate isometric quadriceps and hamstring exercises, and progress to dynamic strength and muscular endurance training. Quadriceps strength is important for knee stability.149
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++
FOCUS ON EVIDENCE
Eitzen and associates64 reported results of a progressive 5-week exercise program with patients (n=100) who had a recent ACL injury (within 3 months) prior to deciding on whether or not to have reconstructive surgery. Pre- and post-tests included isokinetic quadriceps and hamstring strength, four single-leg hop tests, two self-assessment questionnaires, and a global rating of knee function. Both potential copers and noncopers without additional symptomatic injuries were included in the study. The program utilized progressive strength training (heavy resistance open and closed chain); plyometric, balance, and stability exercises; and perturbation training. A standardized response mean for each variable was calculated and demonstrated clinically relevant improvements in both groups. Adverse events (swelling, pain, or knee giving way) occurred in only five subjects.
++
Neuromuscular control. Neuromuscular control is compromised when stabilizing muscles fatigue.113 Emphasize neuromuscular reeducation (proprioceptive training) with stabilization, acceleration, deceleration, and perturbation training in weight-bearing positions.149 Begin with low-intensity, single-plane movements and progress to high-intensity, multiplane movements. These exercises are described in Chapter 8 and summarized in the last section of this chapter.
++
FOCUS ON EVIDENCE
In a randomized, controlled study, 26 level I or level II athletes with an acute ACL injury or rupture of ACL grafts participated in a standard rehabilitation program or a standard rehabilitation program with perturbation training.76 Of those in the perturbation group (n=12), only one had unsuccessful rehabilitation, with the knee giving way while playing football prior to completing the program. In the control group (no perturbation training; n=14), one-half of the subjects had unsuccessful outcomes and were considered at high risk for reinjury at the 6-month follow-up examination. The authors stated that although both groups returned to high-level physical activities, those in the perturbation-training group demonstrated greater long-term success.
+++
Improve Cardiopulmonary Conditioning
++
Utilize a program that is consistent with the patient's goals, such as biking (begin with a stationary bike), jogging (begin with walking on a treadmill), using a ski machine, or swimming.
+++
Progress to Functional Training
++
Develop activity-specific exercises and drills that replicate the demands of the individual's outcome goals.288 Suggestions for functional training are described in the exercise section of this chapter and Chapter 23.
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Ligament Injuries: Surgical and Postoperative Management
++
Ligaments of the knee provide the key stabilizing forces for accessory motions of the knee (see Fig. 21.2). Specifically, these accessory motions are anterior and posterior translation and medial/lateral pivots (valgus/varus/rotation). Strong ligamentous support is necessary, in part, because of the shallow design of the concave tibial articulating surface that allows significant translatory motions if unrestrained. Acute traumatic disruption or chronic laxity of the ligaments results in excessive accessory motions of the joint, which can impair functional abilities. Although injuries to each of the four primary knee ligaments (ACL, PCL, MCL, LCL) are discussed extensively in the literature, the ACL is, by far, the most frequently injured and surgically repaired.19,202
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General considerations and indications for ligament surgery. Factors influencing the decision for surgical reconstruction of a knee ligament include the ligament injured (differences in healing capacities among ligaments), the location and size of the lesion, the degree of instability experienced by the patient, the presence of concomitant pathology such as a meniscal or articular cartilage damage, and the potential for achieving the desired level of function to which the patient wishes to return.1,2,73,133,181,280 The risk of reinjury and prevention of future impairment are also considerations because acute ligament injury, if not managed adequately, can lead to chronic instability.19 In turn, chronic instability is thought to contribute to degeneration of articular cartilage over time and early-onset OA.150
++
Surgical intervention for ligament injury is indicated if the patient has failed to achieve functional goals established in a conservative rehabilitation program or has early degenerative changes of the joint are apparent. Many authors19,32,83,181,258,280 recommend surgical intervention for acute, isolated ACL and LCL injuries after a brief period of acute symptom management in recreationally active individuals. Surgical management of chronic ligament deficiency is advocated when a patient's function has become compromised or when secondary pathology (e.g., meniscus damage, other ligament involvement, articular degeneration) has developed. However, there is no evidence to suggest that ACL reconstruction prevents or reduces the rate of progression of early-onset joint destruction.150
++
Types of ligament surgery. Ligament surgeries are classified as intra-articular, extra-articular, or combined procedures and can be performed using an open, arthroscopically assisted, or all-arthroscopic approach.32,141,181 Initially, intra-articular procedures were performed through an open approach and involved a direct repair of the ligament. The repair was accomplished by reopposing and suturing the torn ligament. Postoperatively, a long period (usually 6 weeks) of immobilization and restricted weight bearing were required because of extensive tissue disruption associated with the open approach and the poor healing qualities of ligamentous tissue.141 Outcomes were unacceptable due to postimmobilization contractures, patellofemoral dysfunction, muscle weakness, and an unacceptably high incidence of rerupture. Consequently, use of direct repair was abandoned as procedures involving intra-articular or extra-articular reconstruction were developed.
++
Intra-articular reconstruction of ligament injuries, which has evolved over the past four decades, has become the primary means by which ACL and PCL injuries are managed surgically. In general terms, reconstruction involves the use of a tissue graft to replicate the function of the damaged ligament and act as an inert restraint of the knee.20,32,141,158,181,199,280 Initially, intra-articular reconstruction procedures also were performed through an open approach. Although the reconstruction restored knee stability, the need for lengthy postoperative immobilization continued.141 Today, intra-articular ligament reconstruction is performed through an arthroscopically assisted or an all-arthroscopic approach, causing far less tissue morbidity and resulting in a more rapid postoperative recovery.
+
++
NOTE: Overviews of intra-articular ACL and PCL reconstruction procedures are described later in this chapter.
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Extra-articular reconstruction procedures, which involve the transposition of dynamic musculotendinous stabilizers or inert restraints around the knee, such as the IT band, were designed to provide external stability to the knee joint. Extra-articular procedures, in common use in the past, particularly for MCL and LCL injuries, are used rarely today as primary procedures because they do not restore normal kinematics to the knee as effectively as intra-articular procedures. Use of extra-articular procedures to augment intra-articular reconstruction in difficult cases also has been shown to have little benefit.141
++
Grafts: Types, healing characteristics, and fixation. Intra-articular reconstruction is achieved through the use of tissue grafts, most often an autograft (the patient's own tissue) or occasionally an allograft (donor tissue) or a synthetic graft (Fig. 21.15).134,177,199,258 An allograft or synthetic graft is used only when a suitable autogenous graft is not available—for example, when a patient's own tissue is not suitable for graft harvesting.141,199 However, there is concern that remodeling and incorporating the graft after implantation may be slower with an allograft (possibly due to sterilization to prevent disease transmission) or a synthetic graft than with an autograft.177 (Refer to Chapter 12 and Box 12.9 for additional information about tissue grafts.)
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++
Although a variety of tissues have been used for knee ligament reconstruction,134,143,158,177,186,199 a bone-patellar tendon-bone autograft has been used reliably and has been considered the gold standard for ACL reconstruction for several decades.32,71,141,143,203 It remains the most frequently selected graft material for this procedure.20,73,82,134,143,158,181 A frequently selected alternative to a patellar tendon graft for ACL reconstruction is a semitendinosus-gracilis tendon graft.71,141,143,186,254,281 Research has shown that the strength and stiffness of a bone-patellar tendon-bone graft and a quadrupled (four-strand) hamstring tendon graft are actually greater than that of the native ACL ligament.254
++
An extensive body of knowledge exists on graft healing, placement, and fixation as well as the strength and stiffness of various tissues selected as grafts and their responses to
++
imposed loads. Most research has focused on grafts for ACL reconstruction.20,29,82,133,143,264
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CLINICAL TIP
Because the characteristics of grafts and graft fixation affect the rehabilitation process and the outcome of surgery, it is important to understand that a graft undergoes a series of changes after implantation as it heals. Initially, there is a period of avascular necrosis during which the graft loses substantial strength. This period is followed by a period of revascularization, then remodeling, and finally maturation, which typically takes at least 1 year. During the first 6 to 8 weeks postoperatively, the graft is most vulnerable to excessive loads because the strength of the graft is derived solely from the fixation device, not the graft itself.20,29,133,134
++
The need for a long postoperative period of immobilization and protected weight bearing after ligament reconstruction has been eliminated following primary ACL reconstruction because of advances in graft selection, preparation, placement, and fixation and because of the evolution of arthroscopic techniques.20,29,264 Nevertheless, there is still a need to carefully select and progress the stresses imposed on the healing graft during early rehabilitation.
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General considerations for rehabilitation. The expected outcomes following surgery and postoperative rehabilitation after ligament reconstruction are: (1) restoration of joint stability and motion, (2) pain-free and stable weight bearing, (3) sufficient postoperative strength and endurance to meet functional demands, and (4) the ability to return to preinjury activities.
++
Successful postoperative outcomes start, whenever possible, with a preoperative program that includes edema control, exercise to minimize atrophy and maintain as much ROM as possible, protected ambulation, and patient education.59,185,220,256 Preoperative intervention is often possible because ligament reconstruction typically is delayed until postinjury symptoms subside. Exercises are similar to those used for the early phase of nonoperative management of ligament injuries discussed in the previous section of this chapter. Depending on the location and extent of injury, an exercise program may be carried out for several weeks to several months before a decision is made to go forward with surgery.185 Regardless of the duration of the preoperative exercise program, exercises should not further irritate the injured tissues or cause additional swelling or pain.
++
The progression and duration of postoperative rehabilitation programs published in the literature vary. No program has been shown to be optimal. Throughout rehabilitation, open communication with the surgeon enables the therapist to discuss any precautions or concerns specific to individual patients and procedures.
++
Regardless of the ligament injured or operative procedures performed, the emphasis of rehabilitation is placed on restoring a patient's functional abilities while protecting the healing graft and preventing postoperative complications and reinjury. Early controlled motion and weight bearing, hallmarks of current-day rehabilitation, have been shown to decrease the incidence of postoperative complications, such as contracture, patellofemoral pain, and muscle atrophy,220,256,259,303 and to allow patients to return to activity as quickly as possible without compromising the integrity of the reconstructed ligament.193,259
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For more than a decade there has been a move away from adherence to strict time-based rehabilitation protocols toward guidelines that are progressed based on the attainment of specific criteria and measurable goals or performance on functional tests.108,155,157,193,204,303 For example, an exercise program is progressed only after full, active knee extension has been achieved or arthrometer testing indicates that a particular level of joint stability is present. A criterion-based progression is advocated to ensure a safe return to high-level sporting activities and to prevent reinjury.193,303
++
CLINICAL TIP
Clinical practice guidelines have been published recently to summarize available evidence and provide recommendations to support evidence-based decision-making during rehabilitation of knee stability following ligament injury and surgery.149
+++
Anterior Cruciate Ligament Reconstruction
++
Unlike the MCL, which heals readily with nonoperative management, the healing capacity of a torn ACL is poor, giving rise to the frequent recommendation for surgical reconstruction to restore knee stability, particularly in the young, active individual.19,133 Although the incidence of reinjury of the knee is lower after ACL reconstruction than with nonoperative management, particularly in patients younger than 25 years of age,63 many individuals who have sustained an acute, primary ACL injury participate in a conservative course of treatment before a decision is made to undergo surgical reconstruction or to continue with nonoperative treatment.64,185
+++
Indications for Surgery
++
Although there are no rigid criteria for patient selection, the most frequently cited indications for ACL reconstruction include the following.19,32,158,181,185,186
++
Disabling instability of the knee due to ACL deficiency caused by a complete or partial acute tear or chronic laxity
Frequent episodes of the knee giving way (buckling) during routine ADL as the result of significantly impaired dynamic knee stability despite a course of nonoperative management
A positive pivot-shift test because an ACL deficit is often associated with a lesion of other structures of the knee, such as the MCL, resulting in rotatory instability of the joint
Injury of the MCL at the time of ACL injury to prevent lax healing of the MCL
High risk of reinjury because of participation in high-demand, high joint-load activities related to work, sports, or recreational activities
+
++
NOTE: Increased anterior translation of the tibia on the femur compared with the contralateral, noninvolved knee, as measured by an arthrometer, is considered a questionable indication because a strong correlation between these measurements of stability and a patient's symptoms of instability has not been established.19
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CONTRAINDICATIONS: Relative, not absolute, contraindications for ACL reconstruction are noted in Box 21.8.19,32,158,186
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BOX 21.8 Relative Contraindications to ACL Reconstruction
Relatively inactive individual with little to no exposure to work, sport, and recreational activities that place high demands on the knee
Ability to make lifestyle modifications to eliminate high-risk activities
Ability to cope with infrequent episodes of instability
Advanced arthritis of the knee
Poor likelihood of complying with postoperative restrictions and adhering to a rehabilitation program
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Surgical approach, graft selection, and harvesting. In the past 30 years, surgical management of the deficient ACL has evolved and continues to be refined with a move away from entirely open reconstruction to the current practice of most procedures now using arthroscopically assisted or endoscopic techniques to reduce tissue morbidity and reduce recovery time.19,20,71,141 In an arthroscopically assisted approach, only the intra-articular portions of the procedure, such as meniscus débridement or repair, enlargement of the intercondylar notch of the femur, or drilling the femoral and tibial bone tunnels, are performed arthroscopically.141
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The most common ACL reconstruction procedure today is an arthroscopically assisted or endoscopic procedure using an autograft. If a bone-patellar tendon-bone graft is selected, it is harvested through a small, longitudinal incision over the patellar tendon from the patient's involved knee20,32,73,158,181 or occasionally from the contralateral knee.258 The central one-third portion of the tendon is dissected along with small bone plugs attached to the tendon. If a semitendinosus-gracilis tendon autograft (hamstring tendon graft) is selected, it is harvested through an incision centered over the tibial insertion of the semitendinosus and gracilis tendons.71,186,254,261,264,273,281
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Although a summary of systematic reviews has shown no significant difference in outcomes following the use of bone-patellar tendon-bone versus hamstring tendon grafts if coupled with appropriate postoperative rehabilitation,149 there are a number of advantages, disadvantages, and potential complications associated with these two classifications of autografts. For example, transition from mechanical fixation to biological fixation is thought to occur more rapidly with a patellar tendon graft, which involves bone-to-bone healing, than with a hamstring tendon graft, which requires tendon-to-bone healing (6 to 8 weeks versus 12 weeks, respectively).264 Other reported advantages and disadvantages of these two types of autografts are summarized in Boxes 21.9 and 21.10.1,71,141,143,162,241,254,261,273,281 It should be noted, however, that recently the use of a bone-hamstring tendon-bone autograft for ACL reconstruction was reported, allowing bone-to-bone healing and affording some of the same advantages associated with a bone-patellar tendon-bone autograft.162
++
Graft placement and fixation. After the graft is harvested and prepared for implantation, the arthroscopic instrumentation is reinserted to drill femoral and tibial bone tunnels.20,83,141,158 Graft placement (see Fig. 21.15) is achieved by passing the graft through the tunnels to its final position in the tibia and femur. Precise, anatomical graft placement is crucial for restoration of joint stability and mobility. Improper graft placement can lead to loss of ROM postoperatively.1 A graft placed too far posteriorly may result in failure to regain full flexion, and a graft placed too far anteriorly may limit extension.29
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BOX 21.9 Advantages and Disadvantages/Complications of the Bone-Patellar Tendon-Bone Autograft Advantages
High tensile strength/stiffness, similar or greater than the ACL
Secure and reliable bone-to-bone graft fixation with interference screws
Rapid revascularization/biological fixation (6 weeks) at the bone-to-bone interface permitting safe, accelerated rehabilitation
Ability to return to preinjury, high-demand activities safely
Disadvantages/Potential Complications Anterior knee pain in area of graft harvest site
Pain during kneeling
Extensor mechanism/patellofemoral dysfunction
Long-term quadriceps muscle weakness
Patellar fracture during graft harvest (rare, but significant adverse effects)
Patellar tendon rupture (rare)
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BOX 21.10 Advantages and Disadvantages/Complications of the Semitendinosus-Gracilis Autograft Advantages
High tensile strength/stiffness greater than ACL with quadrupled graft
No disturbance of epiphyseal plate in skeletally immature patient
Evidence of hamstring tendon regeneration at donor site
Loss of knee flexor muscle strength remediated by 2 years postoperatively
Disadvantages/Potential Complications Tendon-to-bone fixation devices (particularly tibial fixation) not as reliable as bone-to-bone fixation
Longer healing time (12 weeks) at tendon-bone interface
Hamstring muscle strain during early rehabilitation
Short- and long-term knee flexor muscle weakness (not associated with functional limitation)
Possible increased anterior knee translation (not associated with functional limitations)
+
++
NOTE: Limited ROM into extension also may be caused by graft impingement due to an inadequate femoral notch size or buildup of scar tissue in the notch.1 A femoral notchplasty (enlargement of the intercondylar notch) is performed to ensure adequate clearance of the graft as the knee extends.
++
Graft fixation is vital to the success of ACL reconstruction. With a bone-patellar tendon-bone graft, the bone plugs are secured at each end in the prepared tunnels (bone-to-bone fixation) by means of screw fixation (metal or bioabsorbable interference screws).29,32,83,143,158,264 Several types of soft tissue fixation devices have been used to secure a hamstring tendon graft, including endobuttons, washers, and staples. Use of interference and transfixation screws also has been advocated.29,71,41,186,254 Despite these advances, strong tendon-bone fixation, particularly tibial fixation, remains a challenge.
++
An advantage of current-day fixation devices is that they can withstand early but controlled tensile forces placed across the graft with a low risk of compromising the security of the graft itself, provided proper placement and fit of the fixation devices are achieved.20,29,71 This, in turn, permits early initiation of weight bearing and ROM of the knee, both typical elements of contemporary, accelerated rehabilitation programs.21,90,108,157,193,254,259,303
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After graft fixation and prior to closure, the knee is moved through the ROM to check the graft's integrity and the tension on the graft during knee movement. As with graft placement, proper graft tension at the time of fixation has a direct effect on postoperative joint mobility and stability. Too little tension can result in excessive knee laxity and potential instability, and too much tension can limit knee ROM.20 After the incision is closed, a small compression dressing is immediately placed on the knee, and the leg may be placed in a knee immobilizer for protection.
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There are a number of operative and postoperative complications that can compromise outcomes after ACL reconstruction. Some of these complications have been noted (see Boxes 21.9 and 21.10). Even minor technical errors during reconstruction can affect function adversely. As discussed in the previous section, inappropriate placement of the graft or bone tunnels, problems with graft harvesting such as inadequate graft length, and improper graft tension can adversely affect joint stability and mobility.1,252 Insufficient graft length occurs more frequently during hamstring than patellar tendon graft harvesting. If graft fixation is insufficient, graft slippage and early failure can occur.252,254 With a bone-patellar tendon-bone graft, a bone plug can fracture during harvesting or implantation, necessitating an alternative autograft or an allograft.252
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Postoperatively, potential complications are knee pain, loss of motion, persistent strength deficits, and inadequate joint stability.1,186,252 Anterior knee pain at the donor site of a patellar tendon graft or at the patellofemoral joint may affect functional activities. A neuroma of the infrapatellar branch of the saphenous nerve can cause significant knee pain during kneeling.
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Loss of full knee extension and persistent quadriceps weakness are recognized as significant complications after ACL reconstruction, particularly if full extension is not achieved preoperatively.163 There may be permanent damage to the extensor mechanism after patellar tendon graft harvesting, leading to quadriceps weakness or even patellar tendon rupture in rare instances. Limited ROM of the knee may have been present prior to surgery or may develop after surgery. One possible cause is a buildup of scar tissue in the intercondylar notch, necessitating arthroscopic notchplasty. Loss of patellar mobility also may be a source of limited knee ROM. It has been suggested that a patient's preoperative strength and ROM also may have an impact on postoperative knee motion and strength.
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FOCUS ON EVIDENCE
McHugh and associates170 evaluated 102 patients (age 31 ± 1 year) within 2 weeks of primary ACL reconstruction and 6 months after surgery to determine preoperative indicators of postoperative motion loss (lack of full knee extension) and quadriceps weakness. They found that patients with loss of knee extension preoperatively (in comparison to the noninvolved contralateral knee) were more likely to have limited knee extension postoperatively. However, a preoperative deficit of quadriceps muscle strength (≥ 20% compared with contralateral quadriceps strength) was not an indicator of postoperative quadriceps weakness 6 months after surgery.
++
Lastly, graft failure and the need for revision reconstruction may occur even in the absence of risk factors related to surgical technique. It has been shown that graft failure is most likely to occur during the early months after surgery.84 It has also been suggested that the most common cause of graft failure is poor adherence to postoperative rehabilitation, in particular returning to high-risk, high joint-load activities prematurely.1,84,252
+++
Postoperative Management
++
In the past, rehabilitation after ACL reconstruction involved long periods of continuous immobilization of the knee in a position of flexion and an extended period (often 6 to 8 weeks) of restricted weight bearing. Return to full activity often took a full year.30,257 With advances in surgical techniques and a better understanding of graft healing and the impact of stress on the healing graft, early postoperative motion and weight bearing—often referred to as "accelerated rehabilitation"—has become the standard of care after primary ACL reconstruction with an autogenous graft for the active, typically young patient.21,36,90,108,157,193,217,220,256,257,303
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Accelerated rehabilitation is based on the premise that a precisely placed and appropriately tensioned graft not only is strong enough to withstand the stresses of early motion and weight bearing but also responds favorably to these stresses during the healing process.20,36,256,257,259,303
++
Table 21.6 outlines a contemporary, accelerated program for postoperative management after primary ACL reconstruction. The sequence of goals and interventions identified in Table 21.6 and described in the phases of rehabilitation that follow reflects guidelines common to a number of programs published in the literature.*
++
+
++
NOTE: It is important to recognize that although the descriptor "accelerated" is used frequently in the literature to characterize current-day rehabilitation after primary ACL reconstruction, there is no consensus on the initiation, progression, or duration of postoperative exercise, weight bearing, and other interventions.
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Immobilization and Bracing
++
The rationale for a brief period of immobilization and the use of bracing in the early phase of rehabilitation after ACL reconstruction is based on protecting the graft from excessive strain and preventing the loss of full knee extension.20,235,309 However, with advances in graft fixation, the need for and benefits of early versus delayed motion and/or protective bracing have become a point of debate—recommended by some but not by others.20,21,217,256,303
++
Decisions about whether ROM is initiated early after surgery or postoperative bracing is prescribed are based on many factors. They include the surgeon's philosophy, the type of graft used, intraoperative observations about the quality of fixation, comorbidities and concomitant surgical procedures (e.g., meniscus or collateral ligament repair), and an assessment of the patient's expected level of adherence to a postoperative rehabilitation program.108,220
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Types of postoperative bracing. Protective bracing after ACL reconstruction falls into two broad categories: rehabilitative bracing and functional bracing.20,235,309 Rehabilitative bracing, if prescribed, usually is a hinged, range-limiting orthosis with a locking mechanism. It is typically is worn for just the first 6 weeks after surgery. In contrast, a functional brace is worn when returning to high-demand sports or work-related activities to potentially reduce the risk of reinjury.
++
Brace use and initiation and progression of knee ROM. If a rehabilitative brace is prescribed after surgery, it may or may not be locked initially to hold the knee in full extension. (Even though the greatest stress on the graft occurs between 20° of knee flexion and full extension, precise graft placement and tension allow full knee extension without disrupting the graft's integrity.) If locked in full extension for a short period of time, the brace is unlocked for exercise as soon as ROM is permitted. It is worn throughout the day for a few weeks to 6 weeks20 and sometimes is worn during sleep for protection for the first week postoperatively.220 Initially, the brace is locked in full extension during ambulation with crutches in the event of a fall.108,147,220,256,303 When ROM is initiated, the rehabilitative brace can be set to limit the range of knee flexion during exercise and functional activities so that flexion is progressed gradually.
++
CLINICAL TIP
Guidelines for the duration of immobilization in extension and the initiation and progression of knee ROM vary somewhat in the literature.6,20,21,108,186,193,217,220,256,303 The literature supports the initiation of immediate or at least early knee motion (within the first week after primary, isolated ACL reconstruction) to reduce pain and adverse effects on articular cartilage and soft tissues surrounding the joint and improve ROM outcomes. 20,36,149
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Full, active knee extension and 90° to 110° of flexion is expected by 4 to 6 weeks postoperatively. The patient is weaned from brace use at about 6 weeks postoperatively if full extension has been achieved. Depending on the stability of the knee, sometimes the protective brace may need to be worn longer. These timelines are progressed more slowly when ACL reconstruction is combined with another procedure, such as a collateral ligament, meniscus, or articular cartilage repair.217
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Some patients are advised to wear a functional brace to reduce the risk of reinjury during the advanced phases of rehabilitation and when participating in high-demand sports or heavy manual labor after completing their rehabilitation program. However, the effectiveness of functional bracing after ACL reconstruction is unclear because the literature contains conflicting evidence.149
++
Despite the widespread use of protective bracing following ACL reconstruction, the literature provides a critical analysis of its efficacy during early rehabilitation and when returning to high-risk activities.
++
FOCUS ON EVIDENCE
The literature reflects a common belief that protective bracing (rehabilitative and functional) during early recovery and when returning to activities after ACL reconstruction leads to improved outcomes by decreasing pain, joint swelling, and wound drainage by improving knee extension and by protecting the graft from excessive strain and the risk of reinjury. However, results of a recent systematic review by Wright and Fetzer309 of 12 Level I randomized, controlled trials demonstrated that there is insufficient evidence to support the effectiveness of bracing. All but one of these studies focused on bracing during early rehabilitation. The studies reviewed revealed no significant differences in outcomes, such as postoperative pain, anterior-posterior knee stability, ROM, and functional testing, in groups who did and did not use protective bracing during early recovery. No conclusions could be drawn about the effectiveness of functional bracing in preventing reinjury during high-demand activities because the rate of reinjury was so low in the one randomized, prospective study that was identified in the systematic review. The overall conclusion of the investigators was that the available evidence does not support the routine use of protective bracing after ACL reconstruction.
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Weight-Bearing Considerations
++
As with ROM, early weight bearing is possible after primary ACL reconstruction with a bone-patellar tendon-bone or hamstring tendon autograft because of advances in graft fixation. However, recommendations for a period of protected weight bearing immediately after surgery vary, ranging from some degree of restricted weight bearing the first 2 weeks to weight bearing as tolerated with use of two crutches immediately after surgery.21,71,147,193,217,241,256,288,303 Weight bearing is increased during the next 2 to 3 weeks based on the patient's symptoms. Protected weight bearing continues for a longer period of time if other structures in the knee have been injured and/or repaired (e.g., after repair of an articular cartilage defect of a femoral or tibial condyle).303
++
Full weight bearing and ambulation without crutches and with or without an unlocked protective brace usually is permitted by 4 weeks if weight bearing is pain-free and the patient has achieved full, active knee extension and sufficient strength of the quadriceps to control the knee.21,108,186,193,220
++
Weight-bearing recommendations do not appear to be based on the type of graft or graft fixation used or whether protective bracing is worn but rather are determined on an empirical basis. The few randomized studies in the literature indicate that immediate and delayed weight bearing during the first few weeks after surgery produce similar outcomes.20
++
FOCUS ON EVIDENCE
Tyler and colleagues289 conducted a prospective, randomized, controlled study with 49 patients comparing the effects of immediate versus delayed weight bearing during the first 2 weeks after ACL reconstruction with a bone-patellar tendon-bone graft. The immediate weight-bearing group was advised to bear weight as tolerated and discontinue crutch use as soon as they felt comfortable doing so. The delayed weight-bearing group was advised not to wear a shoe on the operated side and remain nonweight-bearing during ambulation with crutches for the first 2 weeks. After that, there were no restrictions placed on the progression of weight bearing. Neither group wore protective bracing. With the exception of weight-bearing status, the rehabilitation program for all patients was the same.
At a mean of 7.3 months, there were no significant differences between groups with respect to knee ROM, knee stability (measured by clinical examination and arthrometer), VMO activation (measured by EMG activity), or overall function. However, patients in the immediate weight-bearing group had a lower incidence of anterior knee pain than patients in the delayed weight-bearing group (8% and 35%, respectively). The investigators concluded that immediate weight bearing did not compromise knee joint stability or function and was beneficial in that it resulted in a lower incidence of postoperative anterior knee pain.
++
A progression of carefully selected exercises and functional activities coupled with patient education is a foundation of rehabilitation following ACL injury and reconstruction.
++
Preoperative exercise. Because surgery typically is delayed after injury until acute symptoms have subsided, there is ample time to implement a preoperative exercise program to restore full knee ROM, particularly extension, prevent atrophy and weakness of thigh musculature, and improve the strength and flexibility of hip and ankle musculature.59,104,185,220,256,303
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Postoperative exercise progression. After reconstruction of the ACL, exercise begins immediately on the first postoperative day. Use of strong grafts, such as bone-patellar tendon-bone and quadrupled hamstring autografts, and reliable graft fixation make early motion possible.21,108,193,217,220,256,303
++
Sometimes CPM is used while a patient is hospitalized or at home after discharge. Although a valid mechanism for controlling postoperative pain and initiating early motion,164,256 it is used less frequently today than in the recent past.108 Two recent systematic reviews indicate no additional long-term benefit with the use of CPM after ACL reconstruction.266,310
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CLINICAL TIP
It is important to remember that a tendon graft goes through a necrotizing process the first 2 to 3 weeks postoperatively before revascularization commences and maturation gradually occurs.20,82,133,134 Therefore, exercises are progressed cautiously during each phase of rehabilitation, even during an accelerated program. If protective bracing has been prescribed, exercises are carried out while wearing the brace.
++
The rate of progression of exercise and functional training after ACL reconstruction depends on many factors. For example, patient-related facts, such as age and preinjury health status, affect the healing process, enabling younger, healthier patients to progress exercises more rapidly. The type of graft and graft fixation also may influence the progression of exercise. Some resources advocate more rapid progression of exercise for bone-to-bone fixation with a patellar tendon graft than for tendon-to-bone fixation with a quadrupled hamstring graft, suggesting that bone-to-bone healing may be faster than soft tissue-to-bone healing.108,220,303 In contrast, others advocate the same accelerated program for both procedures.71,241,254
++
If, in addition to an ACL reconstruction, concomitant injuries are present or were managed surgically, the progression of exercises, as with weight bearing, typically is more gradual than after isolated ACL injury and reconstruction.217
++
Exercises for progressive phases of rehabilitation after ACL reconstruction, summarized in Table 21.6, are described in the following sections. Exercise precautions are noted in Box 21.11.21,90,108,170,193,217,236,256,267,299,303
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Exercise: Maximum Protection Phase
++
During the early postoperative period, a delicate balance exists between adequate protection of the healing graft and donor site and prevention of adhesions, contractures, articular degeneration, muscle weakness, and atrophy associated with immobilization. Early motion places beneficial stresses that strengthen the graft but must be carefully controlled to avoid stretching the graft while in a weakened state, particularly during the first 6 to 8 weeks after implantation.
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BOX 21.11 Exercise Precautions After ACL Reconstruction Resistance Training—General Precautions
Progress exercises more gradually for reconstruction with hamstring tendon graft than bone-patellar tendon-bone graft.
Progress knee flexor strengthening exercises cautiously if a hamstring tendon graft was harvested and knee extensor strengthening if a patellar tendon graft was harvested.
Closed-Chain Training When squatting in an upright position, be sure that the knees do not move anterior to the toes as the hips descend because this increases shear forces on the tibia and could potentially place excess stress on the autograft.
Avoid closed-chain strengthening of the quadriceps between 60° to 90° of knee flexion.*
Open-Chain Training During PRE to strengthen hip musculature, initially place the resistance above the knee until knee control is established.
Avoid resisted, open-chain knee extension (short-arc quadriceps training) between 45° or 30° to full extension for at least 6 weeks or as long as 12 weeks.*
Avoid applying resistance to the distal tibia during quadriceps strengthening.*
++
The following goals and exercise interventions are emphasized during the first 4 weeks after surgery when considerable protection of knee structures is warranted.21,108,147,157,170,193,217,220,256,303
++
Goals. Immediately after surgery through the first few postoperative weeks, in addition to controlling pain and swelling and initiating ambulation with crutches, exercise goals are to prevent reflex inhibition of knee musculature, prevent adhesions, restore knee mobility, regain kinesthetic awareness and neuromuscular control (static and dynamic) of the lower extremity, and improve strength and flexibility of hip and ankle musculature.
++
The goal for knee ROM is to achieve 90° of flexion and full passive extension by the end of the first 1 to 2 weeks as joint swelling subsides and then 110° to 125° of flexion by 3 to 4 weeks.
++
Interventions. Pain, joint swelling, and peripheral edema are controlled in a standard manner. Exercises begin the day of or the day after surgery with an emphasis on: (1) preventing vascular complications (DVTs); (2) activating knee musculature; and (3) reestablishing knee mobility. Patient education during the first phase of rehabilitation focuses on these points in the home exercise program.
++
CLINICAL TIP
It is important to activate and strengthen the quadriceps early in the rehabilitation process to reestablish knee control, particularly for safe weight-bearing activities. However, it is equally important to activate and strengthen the hamstrings as they provide a dynamic restraint to limit anterior translation of the tibia on the femur.
++
When weight-bearing exercises are initiated, they are performed in a protective brace if one has been prescribed. Low-intensity closed-chain exercises and proprioceptive/neuromuscular control training are initiated as soon as weight bearing is permissible. The value of early closed-chain/weight-bearing exercises and proprioceptive/neuromuscular control training for quadriceps control after ACL reconstruction has been supported by many authors and is discussed in the exercise section of this chapter.11,36,59,108,117,157,176,193,234,236,256,259,303
++
The following exercises are advocated for the maximum protection phase.21,90,108,147,157,170,176,193,217,220,234,236,256,299,303
++
++
PRECAUTION: Postpone dynamic activation of the knee flexors if a hamstring graft was used for reconstruction (see Box 21.11).
++
ROM and patellar mobility.
Begin ROM in a protected range. Include therapist-controlled PROM or A-AROM within the patient's comfort level.
Include patellar mobilization to prevent adhesions.
To increase passive knee extension, have the patient assume a supine or long-sitting position and prop the heel on a rolled towel or bolster with the knee unsupported (see Fig. 21.18)
To increase knee flexion, include supine, gravity-assisted wall slides (see Fig. 21.19) or dangle the leg while sitting on the side of a bed.
Stretch hip and ankle musculature if flexibility is limited.
Neuromuscular control/responses, proprioception, stability, and balance.
Begin neuromuscular training with trunk and lower extremity stabilization exercises in bilateral stance. Have the patient wear a protective brace locked in extension, if prescribed. Distribute weight equally on both lower extremities, and put some weight on the hands for support. Have the patient maintain a stable, well-aligned position as alternating resistance with varying directions and speeds is applied at the pelvis.
Progress training with weight-shifting activities and bilateral minisquats in the 0° to 30° range and with stepping and marching movements. Gradually decrease upper extremity support. When the knee is pain-free and full weight bearing is possible, progress to unilateral stabilization activities.
Perform nonresisted, multi-joint movements, such as stationary cycling and exercise on a seated leg press machine or in a semireclining position on a Total Gym® unit, at 3 to 4 weeks. If incision healing allows, begin exercises in a pool.
++
Criteria to progress to next phase. Criteria include:
++
Minimal pain and swelling
Full, active knee extension (no extensor lag)
At least 110° knee flexion
At least 50% to 60% quadriceps strength (measured isometrically at 60°)
Greater than 110° of knee flexion
No evidence of excessive joint laxity (determined by arthrometric measurements)
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Exercise: Moderate Protection/Controlled Motion Phase
++
The moderate protection phase, which begins about 4 to 5 weeks postoperatively or at a point when identified criteria have been met, extends to about 10 to 12 weeks postoperatively. The emphasis of this phase is to achieve full knee ROM and increase strength, dynamic stability, and endurance, as well as normalize gait and neuromuscular control/response time and balance in preparation for a transition to functional activities without compromising the stability of the knee. The hinged, protective brace may be worn for gait and most exercises until about 6 weeks when brace use is gradually discontinued.
++
CLINICAL TIP
By 8 to 10 weeks revascularization of the graft is becoming well established; therefore, exercises can be performed more vigorously while continuing to closely monitor the patient's responses to increasing activity.82,133,134
++
Goals. Rehabilitation goals during the intermediate phase are to attain full ROM (full knee extension and 125° to 135° flexion); improve lower extremity strength and muscular endurance; ambulate without assistive device and protective brace using a normal gait pattern; continue to improve neuromuscular control/response time, proprioception, and balance; and regain cardiopulmonary fitness.
++
Interventions. Include and progress the following interventions during the moderate protection phase.21,90,108,147,157,170,176,193,220,234,236,256,303
++
++
FOCUS ON EVIDENCE
Although an emphasis has been placed on closed-chain strengthening during the past decade or two,36 subsequent studies demonstrated value in including both open- and closed-chain exercises in an ACL rehabilitation program.176 Bynum and colleagues36 conducted a prospective, randomized, controlled study comparing open- and closed-chain rehabilitation after primary ACL reconstruction with a bone-patellar tendon-bone autograft. Immediately after surgery, all patients followed the same exercise program, emphasizing early ROM (against no external resistance) and isometric quadriceps control. All patients wore a protective brace and ambulated with crutches, bearing weight as tolerated. When strengthening exercises were initiated, one group followed an open-chain regimen and the other a closed-chain regimen. One year after surgery, 66% of patients participated in a follow-up examination that included subjective and objective measurements; it was conducted by someone blind to group assignment. Patients in the closed-chain exercise group compared with the open-chain group had significantly less anterior knee pain, closer to normal knee stability as measured by an arthrometer, earlier return to functional activities, and greater overall satisfaction with the outcome of the surgery.
A subsequent prospective, matched study by Mikkelsen and associates,176 which also included closed-chain training at 2 weeks following surgery, demonstrated that the addition of open-chain quadriceps strengthening at 6 weeks postoperatively resulted in no significant differences in anterior knee laxity between the group that performed closed- and open-chain strengthening and the group that performed only closed-chain strengthening. A significantly greater number of the participants who performed the additional open-chain training returned to sports at the prelevel than did those who trained with closed-chain exercises only.
++
Neuromuscular control/responses, proprioception, and balance.
Progress neuromuscular training with stabilization and static and dynamic balance activities in bilateral, progressing to unilateral stance on stable and then unstable surfaces. Focus on developing quick responses to alternating resistance and unexpected perturbations in varying directions.
Emphasis on hip and lumbopelvic stability as well as awareness of proper lower extremity alignment and knee control is crucial to correct pathomechanical alignment or movements.227
Gait training. Practice ambulation in a controlled environment without bracing or with the protective brace unlocked and without crutches. Emphasize symmetrical alignment, step length, and timing to reestablish a normal gait pattern.
Aerobic conditioning. Continue stationary cycling, increasing the duration and speed, or initiate a swimming or pool walking/running program, treadmill walking, or use of an elliptical trainer or stepping machine.
Activity-specific training. Integrate simulated functional activities or components of activities into the exercise program.
++
Criteria to progress to next phase. Criteria to progress to the advanced phases of rehabilitation include:
++
Absence of pain and joint effusion
Full, active knee ROM
At least 75% strength of knee musculature compared to the contralateral side
Hamstrings/quadriceps ratio > 65%
Functional hop test > 70% of contralateral side
No evidence of knee instability on arthrometer readings or clinical examination
+++
Exercise: Minimum Protection/Return to Function Phase
++
The advanced phase of rehabilitation and preparation for a return to a preinjury level of activity begins at about 10 to 12 weeks postoperatively or at a point when the patient has met specified criteria. Most post-ACL reconstruction rehabilitation programs described in the literature continue until about 6 months postoperatively.20,21,108,193, 217,220,303 The intensity and duration of training typically are based on the patient's goals and the level of activity to which the patient wishes to return. Individuals involved in high joint-loading, work-related activities, or competitive sports are advised to participate in a maintenance exercise program.
++
Goals. From 12 to 24 weeks postoperatively, the aim is to further increase strength, endurance, and power; further enhance neuromuscular control and agility; and participate in progressively demanding functional activities.
++
Interventions. Exercise interventions during the final phase of rehabilitation include PRE with an emphasis on eccentric training, advanced closed-chain strengthening (lunges, step-ups, step-downs against elastic resistance); advanced neuromuscular, balance, and agility training with directional changes, acceleration, and deceleration; plyometrics; and activity-specific drills coupled with a gradual return to progressively demanding activities. Patient education emphasizing prevention of reinjury continues throughout the advanced phases of rehabilitation and as the patient returns to full activity. Refer to the exercise section of this chapter and to Chapter 23 for examples of exercises and activities.
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A functional knee brace may be worn to reduce the risk of reinjury during high-demand activities, particularly those that involve turning, twisting, cutting, or jumping motions. As noted previously in this section, conflicting evidence exists for the use of functional bracing following ACL reconstruction.149 For additional information on efficacy of functional bracing, refer to the next section on Outcomes.
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Return to activity. Recommended timelines for returning to vigorous activities, including competitive sports, vary considerably, ranging from as early as 6 months to a year after surgery.21,241,254,259 Criteria to return to a preinjury level of activity must be individualized for each patient and are contingent on clinical examination findings, particularly quadriceps strength, the stability of the knee, and the expected work-related, recreational, or sports-related demands. Box 21.12 identifies criteria, suggested by several sources,104,140,147,193,259,299,303 that should be met prior to a return to high-risk, high joint-loading activities.
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Outcomes
Reconstruction of the ACL followed by a carefully progressed postoperative rehabilitation program is a reliable means of reestablishing knee stability. Long-term success rates following ACL reconstruction range from 82% to 95%, and graft failure leading to recurrent instability is reported to occur in approximately 8% of patients.2 However, outcomes are predicated on numerous factors, including the patient's age, sex, overall health status, and preinjury activity level, the presence or absence of injuries associated with the ACL injury, various aspects of the surgical procedure, postoperative complications, and the patient's adherence to the rehabilitation program. The effects of several of these variables are addressed in this section.
Graft selection and outcomes. Numerous prospective and retrospective studies have been conducted comparing the effects of graft selection on outcomes. Bone-patellar tendon-bone and hamstring tendon autografts are studied most often. An extensive review and analysis of the literature revealed that, although both types of grafts have their merits and limitations (summarized in Boxes 21.9 and 21.10), long-term (2 years or more) functional outcomes are essentially the same.261
Approaches to rehabilitation. There is limited evidence in the literature to determine the effects of variables in a postoperative exercise program, such as the components and rate of progression of rehabilitation and the degree of supervision on outcomes. The inclusion of neuromuscular training, for example, has become an important element of rehabilitation after ACL reconstruction. To investigate its effectiveness, Risberg and colleagues234 conducted a randomized, controlled, single-blind study comparing a program of neuromuscular training to a traditional strength-training program over a 6-month period after ACL reconstruction. At the conclusion of the study, the neuromuscular training group had significantly better scores on selected functional tests than the traditional strength-training group. There were no significant differences between groups in knee pain, joint laxity, proprioception, or knee muscle strength. Although the study did not include long-term follow-up outcomes, the investigators concluded that neuromuscular training is an important component of rehabilitation following ACL reconstruction.
Beynnon and co-investigators21 conducted a prospective, randomized, double-blind study comparing the results of an accelerated (19 weeks) and nonaccelerated (32 weeks) rehabilitation program following ACL reconstruction with bone-patellar tendon-bone autografts. The two programs contained the same components but were implemented over two different timelines. A total of 25 patients entered the study, and 22 patients (10 in the accelerated 19-week program and 12 in the nonaccelerated 32-week program) completed the program and were available for final follow-up. At 24 months postoperatively, there were no significant differences in knee laxity, functional testing, or patient satisfaction and activity level.
The effect of supervision during rehabilitation has also been studied. Specifically, home-based rehabilitation with limited therapist supervision has been compared with clinic-based rehabilitation with therapist supervision throughout the program. Two reviews of the literature revealed that, for the most part, these two approaches produced similar outcomes.20,310 However, all patients who participated in the various studies had some instruction and supervision from a therapist. The reviewers emphasized the importance of therapist-directed assessments and initial instruction in an exercise program but recommended periodic, rather than continuous, supervision over the course of rehabilitation.
Functional bracing. The effect of functional bracing during the intermediate and advanced phases of rehabilitation and its use during high-risk sports after completion of rehabilitation is unclear. Risberg and colleagues235 carried out a prospective investigation in which 60 patients were randomly assigned to a braced or a nonbraced group. After ACL reconstruction with a patellar tendon autograft, patients in the braced group wore a protective brace for 2 weeks and then wore a functional brace most of the time for an additional 10 weeks. At the conclusion of rehabilitation, the braced group was advised to wear the functional brace for all high joint-loading activities. The nonbraced group had no brace at any time during or after rehabilitation. Otherwise, both groups underwent the same rehabilitation program and patient education. At a 2-year follow-up, there were no significant differences between groups for knee ROM, knee joint laxity, muscle strength, functional testing, or incidence of reinjury to the ACL. The results of this study are similar to the findings of a more recent randomized, controlled multicenter study by McDevitt and associates,168 who found that use of an "off-the-shelf" functional brace for 1 year after ACL reconstruction during all high-demand activities (jumping, pivoting, cutting) had no significant impact on knee function or reinjury.
Sterret and colleagues277 also investigated the role of functional bracing in preventing reinjury in patients returning to an advanced, high-demand activity after ACL reconstruction, specifically snow skiing. Over several consecutive ski seasons at a large ski resort, the investigators conducted a prospective, nonrandomized cohort study of 820 skiers who were employees of the ski resort and had undergone ACL reconstruction with a patellar tendon autograft at least 2 years previously. Of the 820 post-ACL reconstruction skier/employees, 257 were considered at significant risk for reinjury of the ACL based on the results of preseason screening. These individuals were given and advised to wear a functional knee brace during skiing. The remaining 563 skier/employees were not determined to be at significant risk for reinjury and were not issued a functional brace.
Analysis of data during the course of the study over several years indicated that 61 ACL reinjuries occurred: 51 in the nonbraced skiers and 10 in the braced skiers. The nonbraced group was 2.74 times more likely to sustain reinjury to the ACL than the braced group. Based on the results of their study, the authors recommended functional knee bracing after recovery from ACL reconstruction for patients returning to the high-risk sport of skiing regardless of their assessed risk of reinjury. The authors, although noting the limitations of this nonrandomized study, suggested that the findings of this study were of interest because of the large number of participants in the study.
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BOX 21.12 Criteria to Return to High-Demand Activities After ACL Reconstruction
No knee pain or joint effusion during final phase of rehabilitation
Full, active knee ROM
Quadriceps strength > 85% to 90% of contralateral side or peak torque/body mass 40% and 60% for men and 30% and 50% for women (tested at 300°/sec and 180°/sec, respectively).
Hamstring strength 100% of contralateral side
Hamstring/quadriceps ratio > 70%
No postoperative history of knee instability/giving way
Negative pivot shift test
Knee stability measured by arthrometer: < 3 mm difference between reconstructed and uninjured side
Proprioceptive testing: 100%
Functional testing (a series of hop, jump, and/or squat tests): > 85% or > 90% of contralateral side or normative values
Acceptable patient-reported score on comprehensive, quantitative knee function measurement tool, such as the International Knee Documentation Committee Subjective Knee Form
+++
Posterior Cruciate Ligament Reconstruction
++
In contrast to injury of the ACL, injury of the PCL is relatively infrequent.307 When an injury does occur, it usually is accompanied by damage to other structures of the knee. There is general agreement that a PCL injury, combined with an injury to another ligament or other structures of the knee, usually warrants early surgical intervention.74,205,206
++
When an isolated PCL injury occurs, most patients respond well to nonoperative management and are able to return to a preinjury level of activity without surgical intervention. However, after a severe PCL injury, an increased incidence of OA in the medial compartment of the knee over time has been observed.307 Motion analysis of the PCL-deficient knee, as the result of an isolated rupture, has demonstrated altered kinematics of the medial compartment of the knee, specifically anterior subluxation of the medial femoral condyle (posterior subluxation of the medial tibial plateau).146 These findings provide a possible explanation for the degenerative changes observed in the PCL-deficient knee and lend support for surgical intervention.
+++
Indications for Surgery
++
Although there is limited consensus, the most frequently cited indications for surgical reconstruction of the PCL include the following.5,44,74,206,280,307
++
Complete tear or avulsion of the PCL with posterolateral, posteromedial, or rotary instability of the knee combined with damage to another ligament and often the menisci or articular cartilage
Isolated, symptomatic, grade 3 PCL tear with greater than 8 to 10 mm posterior displacement compared with the contralateral, noninjured knee, resulting in instability during functional activities
Persistent pain and instability after an unsuccessful course of nonoperative treatment following an isolated PCL injury
Chronic PCL insufficiency associated with posterolateral instability, pain, limitations in functional activities, and deterioration of articular surfaces of the knee
++
There are a number of arthroscopic, arthroscopically assisted, or open procedures available for management of a torn or ruptured PCL. Although an acute boney avulsion occasionally is managed with primary repair, reconstruction is by far the more frequently selected option.74 As with ACL reconstruction, PCL reconstruction involves implantation of a graft to replace the damaged ligament. Graft options using single-bundle or double-bundle reconstruction include a bone-patellar tendon-bone autograft, a hamstring (semitendinosus-gracilis) or quadriceps tendon autograft, an Achilles tendon or anterior tibialis tendon allograft, or, occasionally, a synthetic graft.5,44,74,206,280,307
++
The operative procedure begins with diagnostic arthroscopy followed by graft harvest if an autograft is to be used for reconstruction. There are two broad categories of methods of graft placement—transtibial tunnel and tibial inlay.44 With the transtibial (all-arthroscopic) technique, after femoral and tibial tunnels are drilled and prepared, the graft is drawn through and secured in the tunnels with boney or soft tissue fixation devices. The tibial inlay technique can be performed as an open procedure through a posteromedial incision or less frequently as an arthroscopic procedure. No significant differences in outcomes have been identified following the transtibial versus the open tibial inlay procedures.44
++
Graft placement must be precise to mimic the function of the native PCL regardless of the technique used. Prior to closure, the knee is flexed and extended to be certain that graft placement and tension allow full ROM. After wound closure, a sterile compression dressing is applied, and the knee is immobilized in full extension.
++
Because PCL reconstruction involves the posterior aspect of the knee, there is risk of damage to the popliteal neurovascular bundle. Risk is highest during drilling of the tibial bone tunnel. Postoperatively, bleeding can lead to compartment syndrome. If a patellar tendon autograft was harvested, the patient may experience anterior knee pain and pain during kneeling. If motion is lost postoperatively, usually knee flexion becomes limited. As with any ligament reconstruction, graft failure can occur, leading to loss of joint stability and the need for revision reconstruction.44,74
+++
Postoperative Management
+++
Immobilization, Protective Bracing, and Weight Bearing
++
Initially, the knee is immobilized in a hinged, range-limiting protective brace locked in full extension. The immobilizer is worn during the day and even during sleep for the first 4 to 8 weeks to prevent posterior displacement of the tibia as the result of gravity or sudden contraction of the knee flexors. It may be removed after the first postoperative week for bathing and exercise. It is unlocked or removed for exercise 1 day to a week after surgery.5,44,74,205,206,307 The protective brace remains locked in extension during weight bearing and ambulation for an extended period of time.
++
FOCUS ON EVIDENCE
In theory, protective bracing is prescribed following PCL reconstruction to prevent posterior tibial translation that potentially could disrupt the graft in the early stage of healing. However, the results of a recent literature review indicate that there is no evidence to support this assumption.149
++
In contrast to weight bearing after ACL reconstruction, weight bearing is progressed more gradually after PCL surgery.44,74,205,206,307 The time frame for initiating and progressing weight bearing varies considerably in the literature. Recommendations range from partial weight bearing (about 30%44) immediately after surgery using two crutches and wearing the protective brace locked in extension51,205,206 to nonweight-bearing for a week to 5 weeks postoperatively.74,307 Weight bearing is increased over several weeks while keeping the brace locked in extension. As quadriceps control improves, enabling the patient to fully extend the knee, and pain and joint effusion are well controlled, the brace is unlocked, allowing movement in a protected range during ambulation with crutches and weight-bearing exercises.
++
Crutches are discontinued and full weight bearing with the brace unlocked is permitted when the patient has met specified criteria (Box 21.13). These criteria typically are met at approximately 8 to 10 weeks postoperatively.44,51,205,206 Brace use is then discontinued gradually.
++
After PCL reconstruction many of the postoperative exercises performed during progressive phases of rehabilitation are similar to those following ACL reconstruction (see Table 21.7).44,51,74,205,206 The key differences are that exercises are progressed more gradually, and those that place posterior shear forces on the tibia are postponed during the initial and intermediate phases of rehabilitation when the graft is most vulnerable.
++
Strengthening the quadriceps is emphasized for knee control after PCL reconstruction because it acts as a dynamic restraint to posterior tibial translation. When resistance exercises for hamstring strengthening are initiated during advanced rehabilitation, they are adjusted based on the stability of the knee. Box 21.14 summarizes precautions for exercise and functional activities after PCL reconstruction.44,51,205,206
+++
Exercise: Maximum Protection Phase
++
The emphasis during the first, maximum protection phase of rehabilitation, which extends for 4 to 6 weeks, is to protect the integrity of the graft while simultaneously regaining a functional degree of mobility and developing quadriceps control.44,51,74,205,206
++
BOX 21.13 Suggested Criteria for Ambulation Without Crutches After PCL Reconstruction
Minimal to no pain or joint effusion
Full, active knee extension (no extensor lag) with a straight-leg raise in the supine position.
Passive and active knee flexion from 0° to at least 90°
Quadriceps strength: approximately 70% compared with the contralateral side or at least 4/5 manual muscle test grade
No gait deviations
++
BOX 21.14 Exercise Precautions After PCL Reconstruction General Precautions
Avoid exercises and activities that place excessive posterior shear forces and cause posterior displacement of the tibia on the femur, thus disrupting the healing graft.
Throughout the rehabilitation process, limit the numbers of repetitions of knee flexion to lessen abrasion to the PCL graft.
Early and Intermediate Rehabilitation Begin exercise to restore knee flexion while in a seated position, allowing gravity to passively flex the knee and the hamstrings to remain essentially inactive.
During squatting exercises to increase quadriceps strength:
Avoid excessive trunk flexion, because it causes increased activity in the hamstrings.
Avoid knee flexion past 60° to 70°, because it tends to cause posterior translation of the tibia.
When performing open-chain exercises to strengthen hip musculature, such as resisted SLRs in standing, place resistance above the knee.
Postpone open-chain, active knee flexion against the resistance of gravity (prone or standing) for 6 to 12 weeks.
Advanced Rehabilitation Postpone resistance training for the knee flexors, such as use of a hamstring curl machine, for 5 to 6 months.
When performing resisted hamstring curls, use low-loads.
Avoid downhill inclines during walking, jogging, or hiking.
Avoid activities that involve knee flexion combined with rapid deceleration when one or both feet are planted.
Postpone returning to vigorous functional activities for at least 9 to 12 months.
Consider wearing a functional knee brace during high-demand activities.
++
Goals. During this phase of rehabilitation, goals are to control or reduce acute symptoms (pain, swelling), prevent vascular complications (DVTs), reestablish control of the quadriceps mechanism, maintain patellar mobility, regain approximately 90° of knee flexion by 2 to 4 weeks after initiating knee motion, begin to reestablish neuromuscular control and balance, improve strength and flexibility of the hip and ankle musculature if limited, and improve cardiopulmonary fitness.44,51,205,206
++
Interventions. Control pain and swelling in a standard manner. Immediately after surgery, begin ankle-pumping exercises, patellar-gliding techniques, quadriceps-setting exercises (augmented by neuromuscular electrical stimulation), and four-position SLRs while wearing the protective brace locked in full extension. Use an upper extremity ergometer for aerobic conditioning. Establish a home exercise program.
++
When knee motion is permitted, follow the exercise precautions for early rehabilitation previously noted (see Box 21.14). Begin multiple-angle isometrics of the quadriceps from full extension to 25° to 30° of flexion. Perform assisted knee extension, progressing to active knee extension while seated. To regain knee flexion, begin with gravity-assisted flexion in a seated position. Hold the patient's leg in full knee extension and have the patient control leg lowering as gravity flexes the knee.
++
To the extent that weight-bearing restrictions allow and while wearing the locked brace, begin trunk and lower extremity stabilization exercises and heel raises in a supported standing position (in the parallel bars or with crutches). When it is permissible to unlock the protective brace, begin closed-chain quadriceps strengthening in bilateral stance (terminal knee extension and minisquats) while holding on to a stable surface for support. As with ACL reconstruction, hip and lumbopelvic stabilization is critical to prevent pathomechanical movements at the knee.227 Stretch the hip and ankle musculature, in particular the hamstrings, IT band, and plantarflexors.
++
Criteria to progress to next phase. Criteria to advance to the intermediate phase of treatment include44,51,205,206:
++
Minimal joint swelling
Full, active knee extension (no extensor lag)
At least 100° of knee flexion
A grade of 3/5 quadriceps strength on manual muscle test
Understanding of home program and exercise and activity precaution
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Exercise: Moderate and Minimum Protection Phases
++
Goals and interventions. As with early rehabilitation, the goals and interventions during the intermediate and advanced phases of rehabilitation following PCL reconstruction are similar to those following ACL reconstruction (see Table 21.6). However, the suggested timelines continue to be more extended, particularly for hamstring strengthening.
++
The exercises and activities during the intermediate phase of rehabilitation are essentially an extension of those initiated during the first phase. By 9 to 12 weeks postoperatively, the patient should have achieved full knee ROM (0° to 135°), making it possible to discontinue use of the protective brace if quadriceps control is sufficient.44,51,205,206
++
During the intermediate and advanced phases of rehabilitation, precautions to prevent excessive posterior shear forces on the tibia during exercises and functional activities continue (see Box 21.14). Strengthening focuses on the quadriceps to reestablish full, active knee extension and sufficient strength in the quadriceps, hip, and ankle musculature for functional weight-bearing activities.
++
Initiation of resistance training to improve strength and muscular endurance of the hamstrings is based on the posterior stability of the knee. Strengthening of the knee flexors typically is delayed until 2 to 3 months postoperatively and, when initiated, is progressed cautiously. Begin hamstring strengthening with closed-chain exercises, such as bilateral, progressing to unilateral bridging. A recent review of the literature indicates that an eccentric squat program often is recommended following PCL reconstruction.149 Add open-chain hamstring strengthening (hamstring curls) when posterior knee stability allows.
++
Advanced neuromuscular training with plyometrics, balance activities, and agility drills, progressive aerobic conditioning, and activity-specific training are critical for a safe transition to a full level of functional activities. A full return to vigorous activities after PCL reconstruction may take 9 months to a year.44,51,74,205,206
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Meniscus Tears: Nonoperative Management
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The medial meniscus is injured more frequently than the lateral meniscus. Insult may occur when the foot is fixed on the ground and the femur is rotated internally, as when pivoting, getting out of a car, or receiving a clipping injury. An ACL injury often accompanies a medial meniscus tear. Lateral rotation of the femur on a fixed tibia may tear the lateral meniscus. Simple squatting or trauma may also cause a tear.
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Common Structural and Functional Impairments, Activity Limitations, and Participation Restrictions (Functional Limitations/Disabilities)
++
A meniscus tear can cause acute locking of the knee or chronic symptoms with intermittent catching/locking. Pain during forced hyperextension or maximum flexion occurs along the joint line (due to stress to the coronary ligament) along with joint swelling and some degree of quadriceps atrophy.148 When there is joint catching/locking, the knee does not fully extend, and there is a springy end feel when passive extension is attempted. If the joint is swollen, there is usually slight limitation of flexion or extension. The McMurray test or Apley's compression/distraction test may be positive.153
++
When the meniscus tear is acute, the patient may be unable to bear weight on the involved side. Unexpected locking or giving way during ambulation often occurs, causing safety problems.
++
Often the patient can actively move the leg to "unlock" the knee, or the unlocking happens spontaneously.
Passive manipulative reduction of the medial meniscus may unlock the knee (Fig. 21.16).
Patient position and procedure: Supine. Passively flex the involved knee and hip, and simultaneously rotate the tibia internally and externally. When the knee is fully flexed, externally rotate the tibia and apply a valgus stress at the knee. Hold the tibia in this position, and extend the knee. The meniscus may click into place.
Once reduced, the knee may react as an acute joint lesion. If this occurs, treat as described earlier in the chapter in the section on nonoperative management of joint hypomobility.
After acute symptoms have subsided, exercises should be performed in open- and closed-chain positions to improve strength and endurance in isolated muscle groups and to prepare the patient for functional activities.
++
+++
Meniscus Tears: Surgical and Postoperative Management
++
When a significant tear or rupture of the medial or lateral meniscus occurs or if nonoperative management of a partial tear has been unsuccessful, surgical intervention often is necessary. Current-day surgical procedures are designed to retain as much of the meniscus as possible as a means of preserving the load transmission and shock-absorbing functions of the menisci and to reduce stress on the tibiofemoral articular surfaces.
++
Primary surgical options are partial meniscectomy and meniscal repair, both of which are considered preferable to total meniscectomy.278,286 The location and nature of the tear influences the selection of a procedure, as does the patient's age and level of activity. Tears of the outer area of a meniscus, which has a rich vascular supply, heal well, whereas tears extending into the central portion, where the vascular supply is considerably less, have marginal healing properties (Fig. 21.17).287 Age and the patient's activity level factor into the decision-making process because it has been shown that loss of even a portion of a meniscus increases the long-term risk of articular degeneration.287
++
++
Traditionally, partial meniscectomy has been performed to manage complex, fragmented tears and tears involving the central (middle third), relatively avascular zone of a meniscus.286 In contrast, peripheral tears involving the highly vascular portion of a meniscus have been shown to lend themselves well to repair rather than excision of the torn portion.287 However, if a patient with a central zone tear is young or physically active but older, some sources now advocate repair of the torn meniscus.107,197,198 If there is extensive damage to a major portion of the meniscus and it is determined to be unsalvageable, total meniscectomy remains the only surgical option.286
++
For the relatively young and/or active patient who previously underwent total meniscectomy and now is symptomatic as the result of early osteoarthritic changes in the tibiofemoral joint, a recently developed option—meniscal transplantation—using human allograft tissue has become available.107,200,221
++
The progression of postoperative rehabilitation and the time required to return to full activity after each of these procedures depends on the extent and location of the tear and the type of surgical approach and procedure performed. Rehabilitation proceeds more conservatively after repair or transplantation of a meniscus or total meniscectomy than after partial meniscectomy. Damage and repair or reconstruction of other soft tissues of the knee, such as the ACL, also affect the course and progression of rehabilitation after surgery.
+++
Indications for Surgery
++
Repair of a torn meniscus is indicated in the following situations.107,197,286
++
A lesion in the vascular outer third of the medial or lateral meniscus
A tear extending into the central, relatively avascular third of the meniscus of a young (younger than age 40 to 50) or physically active older (older than age 50) individual
++
CONTRAINDICATIONS: Contraindications include the presence of a tear localized to the inner, avascular third of the meniscus, a tear in which there is considerable tissue fragmentation, or a tear that cannot be completely reopposed during surgery.107
++
Prior to the operative procedure, a comprehensive arthroscopic examination of the joint is performed to determine if a meniscus tear is suitable for repair and to identify any concomitant injuries, such as ACL damage. The meniscus repair itself typically is performed using an arthroscopically assisted open approach or a fully arthroscopic approach.107,187,188,197 The determination of which approach is selected generally is based on the location and nature of the tear.286
++
There are several surgical procedures—referred to as inside-out, outside-in, or all-inside techniques—for meniscus repair. The inside-out and outside-in techniques are arthroscopically assisted, with a portion of the procedure being performed through an incision at the posteromedial or posterolateral aspect of the knee.187,197 The all-inside technique is fully arthroscopic.188,287
++
There are also various suturing techniques with nonabsorbable or bioabsorbable sutures that can be used during the repair. Use of other fixation devices, such as darts or staples, also has been reported. Of the many variations of meniscus repair, the arthroscopically assisted, inside-out suture repair is most common and considered by some in the orthopedic community to be the "gold standard."107,187,197,287
++
At the beginning of the procedure, small incisions are made at the knee for portals, and saline is arthroscopically introduced into the joint to distend the capsule. After the joint has been examined, arthroscopic débridement is performed to remove all unstable tissue fragments and prepare the torn meniscus for repair. During the repair itself (performed endoscopically or through a posteromedial or posterolateral incision), the edges of the tear are closely approximated, and sutures are placed every 3 to 4 mm to ensure complete closure (no gapping) along the tear line. All sutures are tied with the knee fully extended or in 10° of flexion to allow full extension postoperatively without causing undue stress on the repaired meniscus.
++
After closure, a compression dressing, extending above and below the knee, is applied to control postoperative joint effusion, and the knee is placed in an immobilizer.
+
++
NOTE: Detailed descriptions of medial and lateral meniscal allograft transplantation techniques are published in several resources.91,107,200,201,221
++
Complications specific to meniscus surgery include intraoperative damage to the neurovascular bundle at the posterior aspect of the knee during the suturing process. With a medial meniscus repair, there is a risk of damage to the saphenous nerve; with a lateral meniscus repair, there is risk of damage to the peroneal nerve. Postoperatively, these same nerves can become entrapped by adherent scar tissue.187,286,287
++
A flexion contracture or an extensor lag postoperatively compromises knee alignment and stability during gait and functional activities. The risk of failure of the repair is greatest during activities that involve joint loading and knee flexion beyond 45°. This risk is greatest during the first few postoperative months.174, 278
+++
Postoperative Management
++
Factors that influence the components and progression of postoperative rehabilitation after meniscus repair are noted in Box 21.15.51,107,174,197 Some variables permit relatively rapid rehabilitation, whereas others necessitate a more cautious progression. For example, exercise and weight bearing are progressed more rapidly after repair of a peripheral zone tear than after a central tear and after a single tear than after a complex pattern tear.
++
Another factor, malalignment of the knee, affects forces placed on a repaired meniscus and thus influences the progression of weight bearing during ambulation and exercise. With varus alignment, a repaired medial meniscus is subjected to increased stress and increased risk of displacement during healing. Therefore, weight bearing must be progressed more slowly in this situation than is necessary when there is normal alignment of the knee.51
+
++
NOTE: Although timelines vary somewhat in published postoperative guidelines, the progression of exercises presented in the following rehabilitation program is appropriate after isolated meniscus repair in a cruciate-stable knee. These same guidelines are appropriate after meniscal transplantation, although the duration of rehabilitation and protection of the transplanted meniscus is longer.107,221 If a concomitant procedure, such as ligament reconstruction, is performed, adjustments also are made to protect the affected structure.
++
BOX 21.15 Factors Influencing the Progression of Rehabilitation After Meniscus Repair
Location and size of the tear (i.e., the zone[s] affected and their vascularity)
Type of tear (tear pattern and complexity)
Type of surgical fixation device used
Alignment of the knee joint (normal, varus, valgus)
Concomitant injuries (ligament, chondral defect) with or without reconstruction or repair
+++
Immobilization, Protective Bracing, and Weight Bearing
++
Immobilization and protective bracing. The knee is held in full extension, first in the postoperative immobilizer and then in a long-leg brace when the bulky compression dressing is removed a few days after surgery.51,107,286 Occasionally, for carefully selected patients with a peripheral zone repair, no protective bracing is used after the postoperative dressing is removed.187 The patient continues to wear a thigh-high compression stocking to control swelling.
++
To protect the repaired meniscus during the first few postoperative weeks, the range-limiting brace is worn continuously (day and night) and is locked in full extension. However, soon after surgery, it is unlocked periodically during the day to initiate early ROM exercises and for bathing. Depending on the site of the lesion and repair, the protective brace is set to allow 0° to no more than 90° of flexion for the first 2 weeks or longer. Each week the ROM allowed by the brace is increased by about 10° until full flexion has been achieved.107 The brace is unlocked throughout the day as early as 2 weeks if the patient has achieved full knee extension.
++
After a central zone repair, the patient typically wears the brace for about 6 weeks or until adequate quadriceps control has been reestablished. After a meniscal transplant, the brace may be worn a few weeks longer.
++
Weight bearing. Following a peripheral zone repair, partial weight bearing (ranging from 25% to 50%) during ambulation with crutches and with the brace locked in full extension is allowed during the immediate postoperative period (first 2 weeks).107 The percent of body weight permitted during weight bearing is progressed more cautiously after a central zone repair or meniscus transplantation. If quadriceps control is sufficient, full weight bearing may be permitted by 4 weeks after a peripheral repair107 and by 6 to 8 weeks after a central repair or transplantation.51,107,174,200,221
++
FOCUS ON EVIDENCE
A recent review of the literature summarized the results of several studies that compared outcomes of "standard" with "accelerated" rehabilitation programs following several types of meniscus repair procedures.148 In the standard programs, knee ROM and weight bearing were delayed for a period of time after surgery, whereas in the accelerated programs, ROM and weight bearing as tolerated were permitted immediately after surgery. The findings of each of the studies reviewed demonstrated no deleterious effects from accelerated rehabilitation and no significant differences in patient outcomes between the standard versus accelerated groups. It is important to point out, however, that there were conflicting time-frames for the rate of progression of knee motion and weight bearing. Therefore, ROM and weight bearing must be progressed gradually, regardless of the procedure, and must be based on the patient's signs and symptoms.
+++
Exercise: Maximum Protection Phase
++
Exercises and gait training with crutches are begun the first postoperative day. A standard approach (cold, compression, elevation) to control pain, joint effusion, and vascular complications (ankle-pumping exercises) is used. Patient education focuses on establishing a home exercise program and reinforcing weight-bearing precautions. Exercise precautions are noted in Box 21.16.51,107,174,286,287
++
BOX 21.16 Exercise Precautions After Meniscus Repair* General Precautions
Progress exercises and weight bearing more gradually after a central zone meniscus repair or meniscus transplantations than after a peripheral zone repair.
If the patient experiences a clicking sensation in the knee during exercise or weight-bearing activities, report it immediately to the surgeon.
Early and Intermediate Rehabilitation Increase knee flexion gradually, especially after a central zone repair.
If a stationary bicycle is used for cardiopulmonary conditioning, set the seat height as high as possible to limit the range of knee flexion.
During weight-bearing exercises, such as lunges and squats, do not perform knee flexion beyond 45° for 4 weeks or beyond 60° to 70° for 8 weeks. Flexion beyond 60° to 70° places posterior translation forces on a repaired meniscus, increasing the risk of displacement during early healing.
Postpone use of a leg press machine until about 8 weeks. Limit motion from 0° to 60°.
Avoid twisting motions during weight-bearing activities.
Postpone hamstring curls until about 8 weeks.
Advanced Rehabilitation Do not perform exercises that involve deep squatting, deep lunges, twisting, or pivoting for at least 4 to 6 months. (The greater the flexion angle, the greater the stress on the meniscus.)
Do not begin jogging or running program until 5 to 6 months.
Return to Activity Refrain from recreational and sports activities that involve repetitive, high joint compressions and shear forces.
Avoid prolonged squatting in full flexion.
++
Goals. During the first 4 weeks after surgery, exercise goals are to regain functional ROM, prevent patellar restrictions, reestablish control of knee musculature, restore postural stability, improve strength and flexibility of the hip and ankle, and maintain cardiopulmonary fitness. By 4 weeks, the patient should achieve full, active knee extension. Recommendations for maximum flexion during the first 2 weeks vary from 60° to 90°.27,51,107,174,286 After 4 weeks, the patient should attain 120° of knee flexion.107
++
Interventions. During the first 4 weeks after meniscus repair, the following interventions are included.27,51,107,174
++
Knee ROM. CPM may be prescribed at the surgeon's discretion. The day after surgery, begin A-AROM and AROM exercises of the knee within a protected range. Knee flexion may be restricted by a hinged, range-limiting brace. Include exercises such as gravity-assisted knee flexion in a sitting position and with assistance, then progress to active heel slides in a supine position.
Patellar mobility. Teach the patient grade I and II patellar gliding exercises.
Activation of knee musculature.
Emphasize quadriceps control in full extension with quadriceps-setting exercises, assisted SLRs in the supine position, and assisted progression to active open-chain knee extension/flexion in a sitting position for concentric/eccentric quadriceps control. Augment quadriceps activation with neuromuscular electrical stimulation or biofeedback.
Perform hamstring-setting exercises and multiple-angle isometrics.
Neuromuscular control/responses, proprioception, and balance.
Begin balance training in a standing position within the limits of weight-bearing restrictions and with the brace locked in extension.
Emphasize trunk and lower extremity stabilization exercises.
When it is permissible to unlock the brace during carefully controlled weight bearing, initiate bilateral closed-chain exercises, such as minisquats and standing wall slides, initially limiting flexion to no more than 45°.
Flexibility and strength of the hip and ankle musculature.
Stretch the hamstrings and plantarflexors, if restricted.
Begin gluteal and adductor setting exercises the first postoperative day. Perform four-position SLRs with the brace locked or with the brace unlocked when the patient can perform an SLR in supine position without an extensor lag.
Perform bilateral heel raises when 50% weight bearing on the operated extremity is permitted.
Cardiopulmonary function. Use an upper body ergometer for aerobic conditioning exercises.
++
Criteria to progress to next phase. The following criteria should be met:
++
Minimal joint effusion and pain
Evidence of superior gliding of the patella with quadriceps setting
Full, active knee extension (no extensor lag)
Approximately 120° of knee flexion
+++
Exercise: Moderate Protection/Controlled Motion Phase
++
The moderate protection phase extends from 4 to 6 weeks to about 12 weeks postoperatively. The knee brace is discontinued at about 6 to 8 weeks if there is adequate control of the knee and no extensor lag. Use of a cane or single crutch is advisable to provide some degree of protection during ambulation.
++
Goals. Restoring full knee ROM, improving lower extremity flexibility, strength, and muscular endurance, continuing to reestablish neuromuscular control and balance, and improving overall aerobic fitness are emphasized during the moderate protection phase of rehabilitation.
++
Interventions. Include and progress the following exercises and activities during the intermediate phase of rehabilitation.27,51,107,174
++
ROM. Progress low-load, long-duration stretching exercises if the patient is having difficulty achieving full knee ROM.
Muscle performance (strength and muscular endurance).
Initiate stationary cycling against light resistance.
Use elastic resistance for low-intensity, open-chain, and closed-chain exercises.
Progress hip- and ankle-strengthening exercises. Emphasize strengthening of the hip abductors and extensor.
Neuromuscular control/responses, proprioception, and balance. With each of these activities, emphasize maintaining proper lower extremity alignment.
Continue or—if not initiated previously—begin closed-chain exercises. Add disturbed balance activities (perturbation training) standing on an unstable surface, such as a minitrampoline or BOSU.
When full weight bearing is permissible, begin unilateral balance activities, partial lunges, step-ups, and step-downs. Practice walking on an unstable surface, such as high-density foam rubber.
Initiate low-intensity agility drills.
Flexibility of the hip and ankle. Stretch the IT band and rectus femoris after the patient has achieved full knee flexion with hip flexion.
Cardiopulmonary fitness. Begin stationary cycling or a pool-walking program at the beginning of this phase. Initiate treadmill training, land walking, or use of a cross-country ski machine or elliptical trainer at around 9 to 12 weeks.
Functional activities. Gradually resume light functional activities during this phase.
++
Criteria to progress to next phase. By 12 to 16 weeks postoperatively, the following criteria should be met:
++
+++
Exercise: Minimum Protection/Return to Function Phase
++
Some degree of protection is still warranted at the beginning of the final phase of rehabilitation, which typically begins at around 12 to 16 weeks and may continue until 6 to 9 months. The return to a high level of physical activity depends on achieving adequate strength, full, nonpainful ROM, and an acceptable clinical examination.51,107,174
++
Goals. The primary goal of this phase is to prepare the patient to resume a full level of functional activities using normal movement patterns while continuing patient education to reinforce the importance of selecting activities that do not overstress the repaired meniscus (see Box 21.16).
++
Interventions. During advanced resistance training, focus on movement patterns that simulate functional activities. Begin and gradually progress drills, such as plyometric training and agility drills, to improve power, coordination, and rapid response times. Continue to stress the importance of proper trunk and lower extremity alignment. Increase the duration or intensity of the aerobic conditioning program. Transition from a walking program to a jogging/running program, if desired, at about 4 to 6 months. A detailed progression of aerobic conditioning activities after meniscus repair is available in published resources.107,174
++
Outcomes
Repair of a torn medial or lateral meniscus using any one of several surgical techniques is a well-tested procedure designed to preserve these important structures, and it results in predictably successful outcomes. This is particularly true for suture repair of a peripheral zone tear.107,187,287 Although the results of repair of tears extending into the central zone are not as predictable, there is increasing evidence that repairs in this zone heal well and provide long-term relief of symptoms.197,198
Although the use of various surgical techniques and the frequency of concomitant pathologies and surgeries make it difficult to compare outcomes of studies, several generalizations can be made. One of the most important factors influencing outcomes of meniscus repair is the status of the ACL. When an ACL injury occurs in combination with a meniscus tear, patients who undergo ACL reconstruction have better outcomes than patients with ACL deficiency. A recurrent tear of a repaired meniscus occurs more frequently in an ACL-deficient knee than in an ACL-stable knee.198,287
Although the age of a patient typically is cited as a factor influencing the decision of whether to repair a torn meniscus, particularly a tear in the central zone, and although most repairs are performed in patients younger than age 40, a study by Noyes and colleagues197 demonstrated a high success rate in a group of patients 40 years of age or older who had central zone tears. With regard to postoperative rehabilitation, no single protocol has been shown to result in superior outcomes.287
Lastly, short-term results of meniscus transplantation with an allograft appear to be promising but are challenging to summarize because of evolving surgical techniques. Long-term effectiveness of current-day procedures has yet to be determined.91,200,221
+++
Indications for Surgery
++
The following are indications for partial meniscectomy as a surgical option for a tear of the medial or lateral meniscus.286
++
A symptomatic (pain and locking), displaced tear of the meniscus sustained by an older, inactive individual associated with pain and locking of the knee
A tear extending into the central, less vascular third of the meniscus if not determined repairable when arthroscopically visualized and probed
A tear localized to the inner, avascular third of the meniscus
++
Arthroscopic meniscectomy typically is performed on an outpatient basis under local anesthesia. Small incisions are made at the knee for portals (usually three), and saline solution is injected through one of the portals, distending the knee. The torn portion of the meniscus is identified, grasped, and divided endoscopically by knife or scissors and removed by vacuum. Intra-articular debris or loose bodies also are removed. After the knee is irrigated and drained, skin incisions at the portal sites are closed, and a compression dressing is applied to the knee.278,286
+++
Postoperative Management
++
The overall goal of rehabilitation after partial meniscectomy is to restore ROM of the knee and develop strength in the lower extremity to reduce stresses on the knee and protect its articular surfaces. The progression of exercises and functional activities depends on the patient's presenting signs and symptoms.
+++
Immobilization and Weight Bearing
++
A compression dressing is placed on the knee, but it is not necessary to immobilize the knee postoperatively with a splint or motion-controlling orthosis. For the first few postoperative days, cryotherapy, compression, and elevation of the operated leg are used to control edema and pain. Weight bearing is progressed as tolerated.51,286
+++
Exercise: Maximum and Moderate Protection Phases
++
Although the ideal situation is to begin exercise instruction on the day of or after surgery, most patients do not see a therapist for supervised exercise immediately after an outpatient procedure. When a patient is referred for supervised therapy, the emphasis typically is placed on establishing a home exercise program. Under these circumstances, it is preferable to teach the patient initial exercises to reduce atrophy and prevent contracture preoperatively, so he or she can initiate the exercises at home immediately after surgery.
++
After arthroscopic partial meniscectomy, there is no need for an extended period of maximum protection postoperatively, because there is little soft tissue trauma during surgery. However, moderate protection is warranted for approximately 3 to 4 weeks. All exercises and weight-bearing activities should be pain-free and progressed gradually during the first few postoperative weeks.27
++
Goals. During the early phase of rehabilitation, the emphasis of treatment is to control inflammation and pain, reestablish independent ambulation, and restore knee control and ROM.
++
Interventions. Immediately after surgery, begin muscle-setting exercises, SLRs, active knee ROM, and weight bearing as tolerated. Full weight bearing is usually achieved by 4 to 7 days, and at least 90° of knee flexion and full extension are attained by 10 days. Initiate closed-chain exercises and stationary cycling a few days after surgery, or as pain and weight bearing status allow, with the goal of regaining dynamic strength and endurance of the knee.
++
PRECAUTION: Patients who have undergone partial meniscectomy must be cautioned not to push themselves too quickly. Too rapid a progression of exercise can cause recurrent joint effusion and possible damage to articular cartilage.
+++
Exercise: Minimum Protection/Return to Function Phase
++
By 3 or 4 weeks postoperatively, minimum protection of the knee is necessary, but full, pain-free, active knee ROM and a normal gait pattern should be achieved before progressing to high-demand exercises. Resistance training, endurance activities, bilateral and unilateral closed-chain exercises, and proprioceptive/balance training to develop neuromuscular control can all be progressed rapidly. Advanced activities such as plyometrics, maximum effort isokinetic training, and simulated high-demand functional activities can be initiated as early as 4 to 6 weeks or 6 to 8 weeks postoperatively with emphasis on reestablishing normal mechanics in movement.
++
PRECAUTION: High-impact weight-bearing activities such as jogging or jumping, if included in the program, should be added and progressed cautiously to prevent future or additional articular damage to the knee. Improper lower extremity alignment during weight bearing, such as valgus collapse and/or pelvic drop should be corrected prior to advancing with plyometric and high-impact activities.
+
++