Partial resurfacing arthroplasty of the femoral head in avascular necrosis. Methods, indications, and results.

The current study reports results using a partial surface replacement for osteonecrosis of the femoral head. The surgical technique, implant design, and instrumentation cause minor soft tissue disruption and require little bony resection. Thirty-seven prostheses were placed in 33 patients during the past 7 years. The mean age of the patients was 43 years (range, 24-59 years), and the preoperative Ficat classification was Stage III in 26 hips, Stage IV in 10, and Stage II in one hip. For the surviving prostheses, the mean followup was 49 months (range, 24-89 months). Of the 28 surviving implants, 24 continue to function well and the patients have excellent or good hip scores according to the Merle d'Aubigne system. There were nine failures, mainly attributable to the extension of the osteonecrosis. In comparison with alternative techniques, the operative surgery for partial surface replacement is straightforward, requiring little preoperative planning and immediate weightbearing postoperatively. Should failure occur, little bone stock loss is incurred and revision to a total hip replacement is as simple as primary hip arthroplasty.