Cobalt serum levels differ in well functioning Birmingham resurfacing and Birmingham modular THA
Large head modular metal-on-metal total hip replacement (MoMTHR) has been shown to have increased revision rates in the National joint registry and in literature. We reviewed 41 consecutive patients with 44 hips who had large head MoM THR using a Birmingham Hip Resurfacing (BHR) cup/Synergy stem combination between June 2005 and Nov 2009 with a mean followup of 59.5 months. In this series we had a revision rate of 6.8% (3/44) for adverse reaction to metal debris (ARMD), persistent groin pain and instability. Kaplan-Meier analysis showed a mean cumulative survival rate of 79.2% (95% CI: 75.5%-82.9%) In addition there is a subset of 5/44 patients (113%) with mild grade groin pain who may need revision in the future. Based on these findings, we do not recommend performance of large head MoMTHR in the future.