Orthopaedic Hospital

Other

University of Southern California

Fu-Wen Shen

Harry A McKellop

Ronald Salovey

Ron Salovey

The present invention presents methods for making oxidation-resistant and wear-resistant polyethylenes and medical implants made therefrom. Preferably, the implants are components of prosthetic joints, e.g., a bearing component of an artificial hip or knee joint. The resulting oxidation-resistant and wear-resistant polyethylenes and implants are also disclosed.

Oxidation-resistant and wear-resistant polyethylenes for human joint replacements and methods for making them

The present invention discloses methods for enhancing the wear-resistance of polymers, the resulting polymers, and in vivo implants made from such polymers. One aspect of this invention presents a method whereby a polymer is irradiated, preferably with gamma radiation, then thermally treated, such as by remelting of annealing. The resulting polymeric composition preferably has its most oxidized surface layer removed. Another aspect of the invention presents a general method for optimizing the wear resistance and desirable physical and/or chemical properties of a polymer by crosslinking and thermally treating it. The resulting polymeric compositions is wear-resistant and may be fabricated into an in vivo implant.

Crosslinking of polyethylene for low wear using radiation and thermal treatments

A method for improving the wear resistance of an implant, made of polyethylene, by crosslinking its bearing surface layer, while leaving its non-bearing interior uncrosslinked. Such crosslinking may be achieved by electron-beam irradiation or by chemical crosslinking of the implant or the polyethylene from which the implant is made. The resulting implant or polyethylene may be further treated to remove the residual free radicals (generated by the electron beam crosslinking process); to remove residual chemicals (generated by the chemical crosslinking process); to remove its most oxidized layer; to stabilize its size and shape; to improve, by remelting, its oxidation resistance; and/or to reshape it into the final implant. Also presented are the resulting implant and polyethylene.

Wear resistant surface-gradient crosslinked polyethylene

The present invention discloses a method for enhancing the wear-resistance of polymers by crosslinking them, especially before irradiation sterilization. In particular, this invention presents the use of chemically crosslinked ultrahigh molecular weight polyethylene in in vivo implants.

Chemically crosslinked ultrahigh molecular weight polyethylene for artificial human joints

A method for improving the wear resistance of an implant by crosslinking its bearing surface layer, while leaving its non-bearing interior uncrosslinked. Such crosslinking may be achieved by electron-beam irradiation or by chemical crosslinking of the implant. The resulting implant may be further treated to remove the residual free radicals (generated by the electron beam crosslinking process), to remove its most oxidized layer, and/or to stabilize its size. In the case of chemical crosslinking, the resulting implant may be further treated to remove residual chemicals from the crosslinked surface layer.

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Walnut, CA, United States of America

Fu-Wen Shen