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.