Data from 236 studies (17 RCTS) was pooled to investigate the adverse events, revision rates, and reoperation rates associated with metal-on-metal hip resurfacing prostheses compared to total hip arthroplasty (THA) devices. The evidence presented in this analysis suggested that MoMs were revised significantly earlier than THA devices. Revisions and reoperations were more common for MoM than for THA per 1000 person-years, and this difference was consistent with 3 of 4 national joint replacement registries. Dislocations, infection/sepsis, and femoral neck fractures were more frequent with THA than with MoM. Secondary analyses of the outcomes of interest were conducted with discontinued devises removed from the calculations, and these results indicated variable results.