Patent ID: 6986792

Claim:
A bipolar prosthesis, comprising; a. a shell which includes an outer surface for bearing against acetabular tissue, a cavity and a shell portal surface interposed between the shell outer surface and the shell cavity, whereby the shape of the shell outer surface is deeper than hemispherical; b. a liner adapted to fit within the shell cavity, the liner containing a liner cavity adapted to receive a head of a femoral component; c. a continuous, non-split locking ring adapted to fit entirely within the shell cavity in order to retain the head of the femoral component within the liner cavity, the locking ring including a locking ring portal surface abutting the shell portal surface to form a portal for the liner inner cavity through which a head and other portions of a femoral component are adapted to extend, whereby the locking ring is adapted to physically lock a head of a femoral component in the liner cavity; d. wherein the liner includes a first portion of polyethylene which has been treated to improve its crosslinking and wear resistance properties, and the locking ring includes a portion of polyethylene which has not been treated to improve its cross linking and wear resistance properties, said portion of the locking ring thereby featuring greater strength properties than said treated portion of the liner, wherein the shell cavity and the locking ring each contain a groove; and e. a retainer adapted to be captured in the grooves of the shell cavity and the ring in order to retain the locking ring in the shell.