Knee Wear of Antioxidant-Stabilized UHMWPE under Aggressive Accelerated Aging Protocol

Introduction Long-term success of TKA depends on several factors including wear, fracture resistance, and oxidative stability. A recent evaluation has shown that when accelerated aging protocols are extended out to 40 days, an antioxidant-stabilized UHMWPE outperformed non-irradiated GUR 1020, by remarkably retaining its mechanical properties, while the reputed oxidatively stable material experienced a significant decrease in DNI toughness and an increase in oxidation index [1, 2]. Preliminary assessments on the wear performance of crosslinked and remelted UHMWPE, aged up to 14 days, are encouraging [3, 4]; however limited wear results have been reported when an accelerated aging protocol is extended over longer periods. This is important considering 14 days of accelerated aging corresponds to only 4 years in vivo [5], while clinically relevant oxidation may occur at longer periods. This study therefore investigates wear performance of a novel hindered phenol-based antioxidant-stabilized UHMWPE, that has been irradiated to a nominal dose of 75 kGy, henceforth referred to as AOX, and aged for 40 days.