IMPLANT SURVIVAL OF METAL-ON-METAL HIP RESURFACING: A SYSTEMATIC REVIEW

Background Hip resurfacing arthroplasty (HRA) has seen a recent revival with third generation Metal-on-Metal prostheses and is now widely in use. However, safety and effectiveness of hip resurfacing are still questioned. We systematically reviewed peer-reviewed literature on hip resurfacing arthroplasty to address these issues. Objective To evaluate implant survival and functional outcomes of hybrid Metal-on-Metal hip resurfacing arthroplasty (HRA). Method Electronic databases and reference lists were searched from 1988 to May 2010. Identified abstracts were checked for inclusion or exclusion by two independent reviewers. Data were extracted and summarized by one reviewer and verified by a second reviewer. Main study endpoint was implant survival, which we compared with the National Institute of Clinical Excellence (NICE) benchmark. We also evaluated radiological and functional outcomes, failure modes and other adverse events. The quality of evidence was judged using the Grading of Recommendations Assessment, Development and Evaluation system (GRADE). Results We identified 539 articles, of which 29 met the inclusion criteria. The studies included one randomised clinical trial, 27 prospective case series and one retrospective case series. Data were extracted from these 29 articles, totalling 10621 resurfaced hips, providing details on five out of 11 resurfacing devices on the market. Mean follow up ranged from 0.6 to 10.5 years and implant survival ranged from 84% to 100%. Of the 10621 hips, 370 were revised (3.5%), with aseptic loosening as most frequent failure mode. None of the HRA implants used to date met the full 10 year NICE benchmark. Thirteen studies showed satisfactory implant survival percentages compared to the three year NICE entry-benchmark. These 13 studies used the BHR implant (eight studies), the Conserve plus (two studies), the Durom implant (one study), the Cormet 2000 implant (one study) or both the McMinn and the BHR implant (one study).