CHANGES IN HIP MUSCLES AFTER ABOVE-KNEE AMPUTATION

To learn about the changes appearing in hip muscles after an above-kne e amputation, 3-dimensional reconstructions of the hip and thigh regio n of 12 patients with above-knee amputations were made based on transv erse magnetic resonance images, In all patients, the amputations were done at least 2 years before the study and were necessitated by trauma or osteosarcoma, The results show that, at higher amputation levels, the geometry of the once-biarticular muscles was changed, The cleaved muscles (40%-60%) and the intact muscles (0-30%) at the amputated side were atrophied, The amount of atrophy of the intact muscles at the am putated side was related to stump length, To avoid an abduction contra cture in 8 patients with amputations, the iliotibial tract was not fix ed, In 4 of these 8 patients, a flexion contracture was visible, If th e tract was not fixed, the hip extension torque of the gluteus maximus , which inserts into the tract, decreased, As a result, the risk of ap pearance of a flexion contracture increased because the strongest hip flexor (iliopsoas muscle) was not involved in the amputation. Abductio n contracture could be avoided only if the hip adductors were fixed ac curately, especially at higher amputation levels.