Chapter 11: Surface-Oxidized Zirconium

Cobalt chrome alloys articulating against ultra-high molecular weight polyethylene are currently the most popular bearing surfaces for total joint arthroplasty. Ceramic materials wear less due to their greater hardness but carry a risk of implant fracture. Zirconium with an oxidized surface layer has the dual advantage of toughness comparable to metal components and surface hardness comparable to ceramic components. This chapter reviews the performance of oxidized zirconium as an alternative bearing surface for hip and knee arthroplasty. Results integrating in vitro and clinical studies as well as retrievals are presented. In vitro studies have reported increased surface hardness, reduced polyethylene wear, and low cytotoxicity of particles generated from oxidized zirconium. Oxidized zirconium has not been associated with significant material-related adverse events supporting the high safety of this bearing material. However, clinical studies have not yet supported the promise of better clinical performance or longer survival, in part because of the lack of long-term follow-up investigations and in part because of the high survival rates of current-generation cobalt chrome alloy femoral head designs.