CORR Insights^®: A Novel Technique for Assessing Antioxidant Concentration in Retrieved UHMWPE

Excerpt

Improving the wear resistance of load-bearing, articular implants with radiation crosslinked ultra-high-molecular-weight polyethylene (UHMWPE) has been one of the major advances in the field of total joint arthroplasty. Thermal treatments following irradiation are necessary to reduce the concentration of residual free radicals and improve the oxidation resistance of UHMWPE. While radiation crosslinking reduces the mechanical strength, postirradiation melting, the most-effective stabilization method, further decreases the strength of UHMWPE. Antioxidants such as vitamin E and pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)] propionate (PBHP) were introduced in the mid-2000s as an alternative for stabilizing the free radicals, eliminating the need for melting. This improved the mechanical properties of the polymer. Antioxidant stabilization is also expected to prevent the oxidation of highly crosslinked UHMWPE components in vivo in the long-term due to the more recently unveiled mechanisms triggered by the absorption of pro-oxidant lipids and cyclic stress [3]. …