Resurfacing arthroplasty. Femoral head viability.

Although obvious theoretic advantages accrue from resurfacing arthroplasty of the hip, the indications for the procedure are controversial because the failure rate is high and loosening is unacceptably frequent. To determine the role of osteonecrosis in these failures, the viability of bone within the femoral head was determined by histologic examination of bone inside 25 failed femoral resurfacing components. The bone was substantially alive throughout the femoral head in 23 of 25 cases (92%). In two cases, the bone of the femoral head was dead. Both of these hips had clinically failed because of femoral neck fracture. This histologic evaluation indicates that bone death is not an inevitable consequence of femoral head resurfacing and the use of polymethylmethacrylate fixation.