Stress reinforced artificial joint prostheses

Claim 1

A stress-reinforced joint prosthesis element for prolonged or permanent reconstructive implantation in a living body comprising a dense isotropic graphite substrate of predetermined shape having a modulus of elasticity approximating the modulus of elasticity of natural bone, said substrate having a bone joining surface and an articulating joint surface adapted to receive substantial axial skeletal load forces tending to induce tensile strain in the joint prosthesis element transverse to the axial loading forces, and a perimeter surface adjacent said articulating joint surface. a dense adherent isotropic vapor-deposited pyrolytic carbon coating on said isotropic graphite substrate, said vapor-deposited pyrolytic carbon coating having increased strength when placed in compression and presenting a dense, smooth, low friction wear surface at said articulating joint surface, and a smooth exterior surface at said perimeter surface, and a metallic band in closely conforming compressional relationship against said smooth pyrolytic carbon coated perimeter surface adjacent said articulating joint surface with a compressive load from said band upon said perimeter surface which produces a strain at said perimeter surface not exceeding about 0.3% and having a modulus of elasticity at least about 5 times the modulus of elasticity of said carbon coated substrate, whereby said band functions to reduce said tensile strain induced upon application of said skeletal load forces, but said band being located intermediate said bone joining surface and said articulating wear surface such that said band does not carry any substantial portion of axial compressive load transmitted between said articulating wear surface and said bone joining surface upon application of said skeletal load forces.