Postoperative sciatic and femoral nerve palsy with reference to leg lengthening and medialization/lateralization of the hip joint following total hip arthroplasty.

The radiographs and prospective records of 1284 (1152 primary and 135 revisions) Charnley low friction arthroplasties performed by one surgeon were studied in reference to postoperative elongation of the limb and lateralization or medialization of the center of rotation of the hip joint and their effect on postoperative nerve palsy. Displacement of the center of the hip joint in relation to fixed points on the pelvis was measured. In primary low friction arthroplasties, leg lengthening ranged from 0.4 to 4 cm; in the revision group, they ranged from 0.04 to 5.8 cm. Sixty-six hips were lengthened more than 2 cm. The center of rotation of the hip was lateralized in 18.1% of cases and medialized in 61.9%. A single case of postoperative sciatic nerve palsy (the result of laceration of the sciatic nerve at surgery) was identified. These study results indicate that nerve injuries after total hip arthroplasty may be caused by local insult, and may not be related to elongation of the limb or postoperative alteration of the center of rotation of the hip.