Ball and socket bearing for artificial joint

Abstract

A ball and socket joint for implanting in the body is provided wherein the socket portion of the joint can have various orientations with respect to the patient's anatomy, and the orientation used for a particular patient can be selected and / or changed in situ, that is, during or after implantation of the joint. In addition, the configuration of the joint, e.g., constrained versus semi-constrained, as well as the materials making up the socket portion of the joint, e.g., plastic versus metal, can be selected and / or changed in situ. The questions raised in reexamination request Nos. 90 / 004,732, filed Aug. 26, 1997 and 90 / 005,596, filed Jun. 22, 1999, have been considered and the results are reflected in this reissue.

Description

BACKGROUND OF THE INVENTION1. Field Of The InventionThis invention relates to artificial joints and in particular to artificial joints of the ball and socket type.2. Description Of The Prior ArtAs is well known in the art, artificial hip and shoulder joints conventionally employ ball and socket articulations. The socket is embedded in one bony structure, for example, the pelvis for a hip reconstruction. The ball is attached to an arm composed of a neck and a stem or shaft, the stem or shaft being embedded in another bony structure, for example, the femur for a hip reconstruction.A number of methods are known for retaining the ball in the socket. In the most common method, referred to herein as the "semi-constrained" construction, the patient's own anatomy, i.e., his muscles, tendons and ligaments, are used to retain the ball within the socket. For this construction, a hemispherical socket typically is used which allows the ball and its attached arm the maximum amount of movement wit...

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