Lower limb amputation is a common and growing problem in the United States. Current prosthetic technology is insufficient for transfemoral amputees to safely control their prostheses for demanding exercise such as stair climbing. Using a technique called targeted reinnervation, intuitive control of prosthetic devices has been achieved for upper limb amputees. To bring this technique to transfemoral amputees, a comprehensive understanding of the location of motor and sensory nerves is required.
Five lower limbs were dissected and the locations of motor points for 13 muscles of the thigh were documented, as was the location of the posterior femoral cutaneous nerve of the thigh. A transfemoral amputation was performed on one limb to demonstrate the targeted reinnervation procedure. The tibial and common peroneal divisions of the sciatic nerve were coapted to the motor points of the semimembranosus and biceps femoris, respectively. The posterior femoral cutaneous nerve was coapted in end-to-side fashion to the tibial nerve.
The average number of motor points per muscle were as follows: sartorius, 4.75; rectus femoris, 3.25; vastus lateralis, 4.5; vastus intermedius, 4.5; vastus medialis, 4; adductor brevis, 2.3; adductor longus, 3; adductor magnus, 2.7; gracilis, 3; semitendinosus, 1.5; semimembranosus, 2.5; biceps femoris long head, 2.75; and biceps femoris short head, 1.
The results of this study indicate that targeted reinnervation is technically feasible in a transfemoral amputee.