AN ELECTROMYOGRAPHIC STUDY OF THE HIP MUSCLES OF TRANSFEMORAL AMPUTEES IN WALKING

The aim of this study was to obtain insight into the electromyographic activity of the hip muscles after transfemoral amputation and to dete rmine whether the cleaved hip muscles are still functional in locomoti on, The electromyographic activity of the superficial hip muscles of b oth legs was studied in 11 men who had a unilateral transfemoral amput ation, The intact muscles at the intact and amputated side showed the same sequence of activity as did those in healthy subjects, but during a longer period of time, The activity of the cleaved muscles with int act muscle fibers (gluteus maximus, tensor fasciae latae) was dependen t on whether the iliotibial tract was reanchored, If the iliotibial tr act was fixed, the same activity was found in the muscles of the patie nts as in those of healthy subjects, The activity of the cleaved, once biarticular, muscles (sartorius, rectus femoris, hamstring muscles, g racilis) was dependent on whether the muscles were reanchored and on t he level of amputation, If the cleaved muscles were reanchored correct ly, the muscles remained functional in locomotion in patients with an amputation in the distal half of the femur, In patients with high ampu tation levels, these muscles were almost continuously active; they pro bably play a role in fixing the socket.