Sciatic nerve palsy associated with total hip arthroplasty.

Six cases of clinically evident sciatic or peroneal nerve palsy occurred in a consecutive series of 380 total hip arthroplasties (THA). An additional eight cases of peroneal nerve palsy due to pressure from Thomas splint or tight bandages were seen. Factors apparently causing nerve palsy were significant lateralization and lengthening in four cases and dislocation of the hip in one case. The cases with neuroapraxia of the peroneal nerve were seen from the third to the fifth day of Thomas splint immobilization. EMG studies were conducted in all six group 1 patients; at the end of one year the results were good in two cases, fair in three cases, and poor in one case. The results suggest that limb lengthening should be limited to 4 cm to minimize this complication. It was also seen that patients with peroneal nerve palsy due to local compression do well, though some are bothered by mild residual dysesthesia over the dorsum of the foot. In contrast, patients with sciatic nerve palsy do not have such a good outlook.