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 uppermost 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 defined in the inner surface and extending into the end face, at least a portion of the inner surface defining a taper with respect to the central axis, the tapered portion of the inner surface extending below the scallop, a protrusion located below the tapered portion of the inner surface, a lower groove located below the protrusion, and an upper groove formed in a portion of the wall extending below the tapered portion;
• a first liner comprising generally convex first outer portion, the first outer portion including an outwardly-extending tab, an upper bump, and a lower bump, wherein the first liner is formed of a polymer material;
• and
• a second liner comprising a generally convex second outer portion, the second outer portion including a tapered outer wall, wherein the second liner is formed of a metallic material;
• wherein the shell is configured to receive each of the first liner and the second liner;
• wherein when the first liner is seated in the shell, the tab is received in the scallop, the upper bump is received in the upper groove, the lower bump is received in the lower groove and engaged with a lower side of the protrusion, and an interference fit is formed between the first liner and the shell, the interference fit including at least engagement of the upper bump with the upper groove and the lower bump with the lower groove;
• and
• wherein when the second liner is seated in the shell, the tapered outer wall is engaged with the tapered portion of the inner surface upper wall of the shell, and the second liner is retained in the shell by engagement between the tapered portion of the inner surface and the upper wall.