Method for Compression Molding a Cross-linked Preform
This invention relates to improved bearings for use in orthopaedic implant
prosthesis and particularly to methods for making ultra high molecular
weight polyethylene or UHMWPE bearings by molding a cross- linked preform by
the application of sufficient heat and pressure. Such UHMWPE resin is
commonly used for bearings in hip, knee, shoulder and elbow prostheses.
Typically, the stock or the molded bearings are irradiated and subsequently
heat treated or heat annealed. The irradiation generates molecular
cross-links and free radicals. The free radicals are subsequently eliminated
by the heat treating processes.