Modern metal-on-metal hip resurfacing.

For this technology overview, the tools of evidence-based medicine were used to summarize information on the indications, effectiveness, and failure rates of modern metal-on-metal hip resurfacing technology. The task was complicated by the fact that resurfacing arthroplasty is commonly offered only to a subset of patients who are candidates for total hip replacement, often prohibiting direct comparisons. Comprehensive literature searches were conducted to address four key questions addressing revision rates, patient characteristics, effectiveness of treatment, and whether improved technique, surgeon experience, and/or patient selection lead to improved outcomes. Despite data limitations, it is apparent that revision rates are higher after resurfacing than after total hip arthroplasty. Potential prognostic indicators did not yield a consistent predictor of patient-oriented outcomes (eg, pain relief) for either resurfacing arthroplasty or total hip replacement. Because of differences between patients who received hip resurfacing and those who received total hip arthroplasty, the results of studies comparing these techniques cannot be interpreted. Finally, changes in technique and increased experience result in a decrease in revision rates and femoral neck fractures and improved pain and hip scores in resurfacing.