Europium Stearate Increases the Oxidation Resistance of UHMWPE

Introduction: Ultra-high molecular weight polyethylene (UHMWPE) has been ubiquitous as a bearing surface material in joint arthroplasty for decades. Yet, its vulnerability to wear and fatigue failure following oxidation remains a major concern. Although significant gains in wear reduction and oxidation resistance have been achieved with a combination of cross-linking and heat treatments, these gains have been made at the cost of mechanical properties such as ductility and resistance to crack propagation. α-Tocopherol, while an effective antioxidant additive for UHMWPE, has the disadvantage of interfering with cross-linking [. Alternative methods for improving the oxidation resistance of UHMWPE are therefore warranted. We have successfully tested europium, a representative element from the lanthanide group, as a stabilization agent to preserve the mechanical properties of UHMWPE subjected to an oxidative challenge [1]. In this study, we hypothesized that the effectiveness of the europium additive is associated with decreased oxidation of UHMWPE.