A 16-year-old boy has a deep laceration of the left lower thigh. The bleeding is stopped. On physical examination, he has a loss of sensation in the lateral left foot and movement in the left foot. The wound is surgically repaired, including nerve, and he receives physical therapy. How long will it take him to regain the use of his left foot?

Laceration of the tibial nerve results in Wallerian degeneration distal to the injury. The realignment of the nerve is accompanied by axonal sprouting. The new axons find the residual myelin sheaths and grow down at the rate of about 2 mm/day, taking 1 year to traverse the length of the calf. There can be reinnervation of the muscle, but there is a type grouping of the muscle fascicles that are reinnervated. Physical therapy can aid in the interim. Complete restoration of motor and sensory functions may not occur.