Chapter 20: The Hip

Introduction

The hip is similar to the glenohumeral joint in that it is a triaxial joint, functions in all three planes, and is the proximal link to its extremity. In contrast to the highly mobile shoulder, however, the hip is a stable joint that is adapted for upright standing and weight bearing activities. At the same time, at least 120° of hip flexion and 20° each of abduction and external rotation are necessary to carry out activities of daily living (ADLs) in what is considered a "normal" manner.¹²⁰ Because forces from the lower extremities are transmitted upward through the hips to the pelvis and trunk during gait and other lower extremity activities, and because the hips support the weight of the head, trunk, and upper extremities, the health of the hip joint is vital for most functional activities.

This chapter is divided into three major sections. The first section briefly reviews the anatomy and function of the hip and its relation to the pelvis, lumbar spine, and knee. The second section describes common disorders of the hip and provides guidelines for conservative and postoperative management, expanding on the information and principles of management presented in Chapters 10, 11, 12, 13. The reader should be familiar with that material as well as the components of a comprehensive examination of the hip and pelvis before determining a diagnosis and establishing a therapeutic exercise program. The third section describes exercise interventions commonly used to meet the treatment goals for the hip region.

Structure and Function of the Hip

The pelvic girdle links the lower extremity to the trunk and plays a significant role in the function of the hip as well as the spinal joints. The proximal femur and the pelvis comprise the hip joint (Fig. 20.1). The unique characteristics of the pelvis and femur that affect hip function are reviewed in this section. The function of the pelvis with respect to spinal mechanics is described in greater detail in Chapter 14.

Anatomical Characteristics of the Hip Region

Bony Structures

The structure of the pelvis and femur are designed for weight bearing and transmitting proximally and distally generated forces through the hip joint.

The Pelvis

Each innominate bone of the pelvis is formed by the union of the ilium, ischium, and pubic bones and therefore is a structural unit. The right and left innominate bones articulate anteriorly with each other at the pubic symphysis and posteriorly with the sacrum at the two sacroiliac joints.⁹³ Slight motion occurs at these three joints to help attenuate forces transmitted through the pelvic region, but ...