Patent ID: 7431874

Claim:
A method of making an oxidation and wear resistant ultrahigh molecular weight polyethylene (UHMWPE) for use in a medical implant, wherein the method comprises: (a) providing consolidated and cross-linked UHMWPE that has been irradiated with ionizing radiation; (b) doping the consolidated and cross-linked UHMWPE with vitamin E by diffusion, thereby allowing formation of a gradient of vitamin E in the consolidated and cross-linked UHMWPE; and (c) annealing the consolidated and cross-linked UHMWPE at a temperature below its melting point to increase the uniformity of the vitamin E distribution in the consolidated and cross-linked UHMWPE such that the vitamin E can react with free radicals throughout the consolidated and cross-linked UHMWPE, wherein the method provides a consolidated and cross-linked UHMWPE that is oxidation and wear resistant and can be used in a medical implant.