Early Failure of a Ceramic-on-Metal Total Hip Arthroplasty

The total hip arthroplasty procedure has improved substantially over the past two decades, including the design, materials used, and the fixation. Minimizing bearing surface wear has become a determinant of long-term implant survival. Approaches to minimize bearing surface wear have included improvement in polyethylene as well as the introduction of hard-on-hard bearing couples. Presently, the most commonly used hard bearing surfaces include metal-on-metal (MOM) and ceramic-on-ceramic (COC) couples. Both have excellent tribological properties, but they also have limitations. Second-generation MOM articulations have lower wear rates compared with metal-on-ultra-high-molecular-weight polyethylene (UHMWPE)1-3. However, despite lower volumetric wear, the wear particles are very small and their presence locally and systemically is concerning4-11. COC articulations have better wear properties than MOM and UHMWPE couples12-17, but issues such as squeaking18,19 and implant fracture remain problematic16,20,21. In the hope of overcoming the adverse issues of MOM and COC bearing couples, an innovative ceramic-on-metal (COM) articulation, utilizing a ceramic head and metal liner, has been recently introduced. Proposed advantages of COM couples include reduced wear, with resultant lower serum metal ion levels compared with MOM12,17,22-24, although COM and COC couples have similar wear rates12,24,25. Adverse soft-tissue reactions are a well-known complication of MOM hip resurfacing arthroplasty7,26-28 as well as contemporary MOM total hip arthroplasty29,30. Such soft-tissue reactions have not been reported with COM bearings; however, these devices have had limited use and only short-term follow-up. We report the case of a patient who experienced early failure of a COM total hip arthroplasty. The patient was informed that data concerning her case would be …