Recent advances in above-knee prosthetics.

1 Executive Director, Committee on Prosthetics Research and Development, National Research Council, 2101 Constitution Ave., N.W., Washington, D.C. 20418. During the past few years, many innovations have been introduced into the practice of above-knee prosthetics. Most of the literature on the new practices has been provided by the innovators, and therefore the reports and articles on the subject generally are limited to a single approach. It is the purpose of this article to survey past and present practices and to set forth, as accurately as possible, a perspective of procedures and devices available today for the management of the above-knee amputee. Amputation through the thigh results in distinct functional losses. The obvious ones are loss of support by the long bones and loss of joints, resulting in inability to stand and move extensively from place to place. In addition, the appearance of the patient becomes altered from the "normal" in both static and dynamic conditions. Lost support and mobility can be replaced to some extent by the use of a wheelchair or crutches or both, but it has been shown that use of an articulated prosthesis is the most effective means of compensating for these losses. An amputee with a functional prosthesis can negotiate stairs, ramps, and other obstacles and, therefore, can move through areas that would be impracticable if not impossible for a wheelchair. Crutches, properly used, offer a great deal of facility of movement but require the use of considerably more energy than a well-fitted and -aligned above-knee prosthesis, or even a peg leg (2,19). Also, when crutches are used the hands are not free during ambulation. Another argument for the use of a functional prosthesis is that a fairly normal appearance can be achieved. The basic functional prosthesis for the above-knee amputee consists of a socket, a knee unit, a shank, and a foot-ankle unit. In cases where it is not deemed advisable to keep the socket in place by air pressure (suction socket), suspension must be provided by a belt about the pelvic area or by a shoulder harness. Not so many years ago it was common practice for the prosthetist to make in his shop nearly every part for a prosthesis from basic materials such as wood, steel, and leather. This practice was time-consuming and wasteful. To eliminate as much manual work as possible, the prosthetist today designs and fabricates the socket from basic materials to fit each patient individually, but uses prefabricated components, which he purchases from manufacturers, for the rest of the prosthesis (2, 16).