UHMWPE and vitamin E bioactivity: an emerging perspective.

Ultra-high molecular weight polyethylene (UHMWPE) is a semicrystalline biomaterial widely used in the components for articular prosthesis for its excellent mechanical qualities. Two major problems limit the UHMWPE prosthesis life-wearing and delamination, both phenomena being mainly due to chemical oxidation of polymer. Wearing causes the release of generated particulate that triggers a macrophage reaction leading to chronic inflammation and osteolysis, while delamination, due to the mechanical stress, macroscopically alters the surfaces. The most diffused method to reduce wearing is UHMWPE molecular cross-linking by high-energy irradiation followed by melting that also reduces polymer fatigue strength. For this reason, the use of vitamin E (alpha-tocopherol), as an anti-oxidative and biocompatible additive for normal and cross-linked UHMWPE, has been suggested as an alternative method to improve polymer wearing resistance without altering its mechanical strength. This paper describes briefly the rationale of vitamin E as UHMWPE additive and its possible use as an emerging perspective in the orthopaedic field.