Somatotopic Configuration of Distal Residual Limb Tissues in Lower Extremity Amputations

A stair-step (BKA) or fishmouth (AKA) incision will be made. Tibial and fibular or femoral osteotomies will be performed. Segments of the tibialis anterior (TA), peroneus longus (PL), lateral gastrocnemius (LG) and tibialis posterior (TP) muscles will be isolated, as well as the quadriceps (Q) and hamstring (H) groups in the AKA model; if it is not possible to preserve native innervation to these muscles, functional motor units will be constructed from muscle coapted to the appropriate motor nerve endings. The distal tibial and peroneal nerves will be redirected to skin patches in the distal or proximal thigh. Coaptation of the TA/LG, PL/TP and Q/H muscles will then be performed to promote dynamic coupling of these agonist/antagonist pairs. The skin envelope will then be closed in layers over percutaneous drains.