Acetabular cup assembly for multiple bearing materials

Abstract

A modular acetabular cup assembly for use with multiple bearing liners is disclosed. The acetabular cup assembly includes a shell having a tapered inner wall and two circumferential grooves. The shell may be used with polyethylene, ceramic, metal, and other types of liners.

1 . An acetabular cup system, comprising:
 a shell having a generally concave inner surface, an outer surface, an end face formed at an upper end of the shell, an apex formed at a lower end of the shell, and a central axis extending through the apex, the inner surface including:
 a plurality of scallops formed in the inner surface, the scallops being positioned adjacent to the end face, 
 a tapered surface positioned below the end face, 
 a protrusion extending from the inner surface, the protrusion positioned below the tapered surface, and 
 a lower groove formed in the inner surface and positioned below the protrusion; 
   a first liner including a generally convex first outer portion, the first outer portion including a plurality of outwardly-extending tabs arranged and configured to interact with the plurality of scallops, and a lower rib arranged and configured to couple with the lower groove, wherein the first liner is formed of a polymer material; and   a second liner including a generally convex second outer portion, the second outer portion including a tapered outer wall arranged and configured to mate with the tapered surface formed on the inner surface of the shell, wherein the second liner is formed of a metallic material;   wherein:   the shell is configured to selectively receive each of the first liner and the second liner;   when the first liner is seated in the shell, the plurality of outwardly-extending tabs are received in the plurality of scallops, respectively, and the lower rib is received in the lower groove thereby establishing an interference fit between the first liner and the shell; and   when the second liner is seated in the shell, the tapered outer wall formed on the second liner is engaged with the tapered surface formed on the inner surface of the shell so that the second liner is retained in the shell.   
     
     
         2 . The system of  claim 1 , wherein:
 the inner surface of the shell further includes an upper groove; and   the first liner includes an upper rib arranged and configured to couple with the upper groove when the first liner is seated in the shell.   
     
     
         3 . The system of  claim 2  wherein the protrusion is positioned between the lower and upper grooves.