Patent ID: 8679187

Claim:
An acetabular cup assembly, comprising: a. a shell, the shell having a generally hemispherical concave inner surface, an outer surface, a face, and an apex, said inner surface further comprising an inner wall, the inner surface forming a first groove recessed into the shell, a second groove recessed into the shell, and a protrusion protruding from the shell, the protrusion located between said first groove and said second groove, said second groove being closer to the apex of the shell, wherein the first groove and the second groove are located below the inner wall; and b. a liner adapted to fit within said inner surface of said shell, the liner comprising an inner portion and a generally convex outer portion, said outer portion including a first bump and a second bump, said second bump being closer to the apex of said generally convex outer surface; c. said first and second grooves in combination with said protrusion of said shell and said first and second bumps of said liner forming an interference fit between said shell and said liner such that the push-out force required to separate the shell from the liner is greater than the push-in force required to seat the liner in the shell.