Patent ID: 8641959

Claim:
A method of incorporating a non-eluting amount of α-tocopherol into UHMWPE to make an implant component having a bearing surface, the method comprising: (a) machining a consolidated UHMWPE or molding nascent UHMWPE powder to make a preform; (b) irradiating the preform with high energy radiation to a dose of 5 to 20 MRad; (c) doping the irradiated preform by exposing it to an antioxidant composition comprising α-tocopherol at a temperature greater than 30° C. and below the crystalline melting point of the UHMWPE; (d) removing the doped preform from exposure to the antioxidant composition; and then (e) homogenizing the doped preform by heating at a temperature above 30° C. and below the melting point of the UHMWPE; followed by (f) making the implant component from the doped preform by machining greater than or equal to 1 mm of material but less than or equal to 15 mm from the doped preform to make the implant component, and (g) packaging and sterilizing the implant component, wherein the vitamin E index throughout the implant is 0.01 or greater, and 0.2 or less.