An orthosis is prescribed by a referring health-care provider as part of a treatment plan. When appropriately prescribed and utilized by the wearer correctly, an orthosis applies a series of forces to regions of the body to control motion(s) of the respective segment(s) (i.e., force systems). Essentially, orthoses function as motion control devices and are commonly utilized in concert with other medical or rehabilitation treatments. If one understands this fundamental concept of an orthosis, then patient evaluation and subsequent orthosis prescription formulation, design, and construction as well as optimal fit and function assessments are more clearly targeted. This chapter provides an overview of orthotic management principles and practices with an emphasis on the biomechanical motion(s) that the orthosis is designed to influence.
The fundamentals of orthotic management as part of a treatment plan are founded on a unique combination of normal and abnormal systems anatomy and physiology, which commonly extend beyond the neuromuscular and skeletal systems and include other disciplines of knowledge such as biomechanics, pathomechanics, material science, engineering, normal and abnormal psychology, and other sciences. Integration of this body of knowledge into a treatment plan for rehabilitation requires some basic guiding factors to ensure the orthosis creates optimal fit and functional performance for the wearer. Because biomechanical motion control is a common objective of the majority of orthoses, an important philosophy is to preserve as much natural movement so that the orthosis(es) impose the least constraint to allow the wearer to function to the best of his/her ability. To successfully implement a minimalist strategy of orthotic intervention, other rehabilitation therapies (i.e., physical therapy, occupational therapy) often need to be combined in tandem with orthotic management to optimize the functional outcome for the person who will wear the orthosis(es).
To gain a full appreciation of how orthoses interact with the body segments targeted for biomechanical motion control, a basic understanding of biomechanics, mechanics, force systems, and normal and pathological gait is necessary. Therefore, this chapter also provides a practical review of these fundamental principles that allow orthoses to effectively apply force system(s) to the body. In considering the outcome of the orthosis on the user's efficiency and function, one must be cognizant that an orthosis can only apply a force when the device is worn, and that the manner in which the orthosis is applied determines the device's functional capabilities. In addition, the wearer's "interaction" with the device, such as his/her adaptation, learning, and dose response, are also of considerable importance to the effectiveness of the orthosis as part of the overall treatment plan.
Classification Systems and Nomenclature
The International Standards Organization (ISO) (http://www.iso.org) has created a classification system of orthoses, including terminology and nomenclature (ISO 8540-3:1989 Prosthetics and Orthotics—Vocabulary, Terms relating to external orthoses. Geneva, Switzerland: International Standards Organization; 1989).