Acetabular cup assembly for multiple bearing materials

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, wherein the inner surface comprises an inwardly-facing scallop positioned adjacent the end face, an upper wall defining a taper with respect to the central axis and extending below the scallop, a lower wall located below the upper wall, a protrusion located below the lower wall, and a lower groove located below the protrusion, wherein the lower groove is partially defined by the protrusion;
• a polymer liner comprising a plurality of tabs sized and shaped to be received in the scallops, and a lower bump sized and shaped to be received in the lower groove;
• a metal liner comprising a tapered outer surface;
• a locking mechanism including the lower groove of the shell and the lower bump of the polymer liner, wherein the locking mechanism has a locking state in which the lower bump is engaged with the lower groove, an interference fit is formed between the polymer liner and the shell, and the locking mechanism couples the polymer liner with the shell, and wherein the interference fit includes engagement of the bump with the groove;
• and
• an engagement mechanism including the upper wall of the shell and the tapered outer surface of the metal liner, wherein the engagement mechanism has an engaged state in which the upper wall is engaged with the tapered outer surface and the engagement mechanism couples the metal liner with the shell.

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.