ACETABULAR CUP POSITIONING INSERT

摘要

An acetabular cup for use as a prosthetic implant has an insert (12) with a body (16) including a central bore (18) for receiving a positioning rod (22) therein. A key element (20) is formed on the bore (18) and is adapted to align the positioning rod (22). The insert (12) has a locating element (58) formed on an outer surface of the body (16) and also includes spring elements (19) extending radially outwardly from the body (16). The acetabular cup (14) has a generally hemispherical shell member (15) coupled to the outer surface of the insert (12). The shell (15) has an outer surface (30) for engaging the acetabulum and an inner surface (32) having a circumferential groove (36) for receiving the spring elements (19). The spring elements (19) may be deflected radially inwardly out of engagement with the groove (36) for releasing the insert (12) form the shell (15). The shell (15) has a plurality of apertures (34) extending from its inner (32) to its outer surface (30), which apertures (34) are located in an asymmetrical pattern about the shell (15). The shell (15) includes a recess (62) on its open end for receiving the locating element (58) on the insert (12) to align the insert (12) at a predetermined orientation with respect to the apertures (34) in the shell (15). The engagement of the insert (12) onto the shell (15) and the engagement of the locating element (58) in the recess (62) aligns the key element on the central bore (18) and, therefore, the positioning rod (22) at a predetermined orientation with respect to the apertures (34) in the shell (15).