Contributory factors and etiology of sciatic nerve palsy in total hip arthroplasty.

Twenty-three peroneal and sciatic nerve palsies occurred in 21 patients following hip arthroplasty. Apparent risk factors included revision operations, being female, and significant lengthening of the extremity. The amount of lengthening was correlated with the development of either a peroneal palsy or sciatic nerve palsy. In cases of peroneal palsy the average lengthening was 2.7 cm (1.9 cm-3.7 cm) in comparison with 4.4 cm (4.0 cm-5.1 cm) for sciatic nerve palsies. Seven of these nerve palsies occurred among 614 consecutive patients treated at one institution during the period 1983-1985. This corresponded to an overall incidence of 1.1%. Electromyography demonstrated that peroneal stretch palsies originated primarily at the level of the neck of the fibula with some diffuse but lesser involvement along the proximal course of the peroneal division of the sciatic nerve.