US 4,822,369 AGranted

Bone joint prosthesis

OwnerGerard Oueveau, Jacques Moulininventors

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Abstract

An improved bone joint prosthesis, particularly a whole hip or shoulder prosthesis, provides long life and prevents dislocation. The cotyle has a resilient, shock absorptive layer sandwiched between inner and outer hemispheric elements. The inner element is coated with a low friction coating which cooperates with the head to provide smooth operation and extended life. Materials which may be used include a high density reticulated polyethylene on the cotyle surface in combination with an alumina head. Particularly good results are obtained using a gold cotyle surface in combination with a highly polished chromium oxide head. A retainer which may be readily fastened to the cotyle during implantation is provided to prevent dislocation of the femoral head from the cotyle. In a preferred embodiment, the lip of the retainer is resilient and permits limited displacement of the head while preventing complete dislocation.

Claims14

Dependent claims

A hip or shoulder prosthesis for connecting a thigh bone to a pelvis or a humerous to a scapula comprising a shaft to penetrate the thigh bone or humerus;

a substantially spherical head having an outer hemispherical surface with a maximum diameter fastened to the shaft;
a cotyle adapted to be fastened to the pelvis or scapula with an adhesive, the cotyle comprising an inner, substantially hemispherical, rigid shell having a substantially hemispherical cavity to receive the head, the cavity having an inner surface being formed of an abrasion resistant, low friction material, an outer, substantially hemispherical rigid shell, the inner shell sized relative to the outer shell to provide a space therebetween, a resilient shock absorption layer between the inner and outer shells and in intimate contact therewith, the resilient shock absorption layer being thicker than the internal and external shells;
at least one of the shells having a plurality of ridges formed therein to enhance the rigidity of said shell, each of the ridges being generally convex on one side of the shell and generally concave on the other side of the shell;
and a retainer fixed to the cotyle, the retainer comprising a retaining lip having an inside diameter less than the maximum diameter of the head to prevent dislocation of the head from the cotyle cavity.

1 more element

Dependencies are inferred from the claim text.