Fatigue toughness of irradiated vitamin E/UHMWPE blends

Radiation cross‐linked ultrahigh molecular weight polyethylenes (UHMWPEs) have become the standard‐of‐care in total joint replacements (TJR) in the last decade because of their superior wear resistance in comparison with previously used “conventional” gamma sterilized UHMWPE. Some first generation radiation cross‐linked UHMWPEs were stabilized against oxidation by post‐irradiation melting, which significantly reduced their fatigue crack propagation resistance or fatigue toughness. Second generation cross‐linked UHMWPEs incorporated instead an antioxidant such as vitamin E, eliminating the need for melting. In this study, we investigated the fatigue crack propagation resistance and the impact toughness of vitamin E‐blended and radiation cross‐linked UHMWPEs as a function of vitamin E concentration and radiation dose. Both properties were strongly dependent on the cross‐link density and they showed a good correlation with each other (R² = 0.89).