Abstract: An acetabular cup assembly includes a shell component, a liner component, and means for retaining the liner in the shell including a spherical profile thread spiraling around a portion of each of the shell and liner.

Abstract: An acetabular cup assembly 10 that uses the mating contour of its bearing component 20 and its shell component 30 to provide a reliable interlocking engagement to secure the bearing component to the shell component is disclosed. Bearing component 20 includes end surface 24 and a convex spherical surface 22, which extends beyond its lateral diametrical plane 23, making the shape of the bearing component slightly greater than a hemisphere. Shell component 30 includes a concave inner surface 36 defining an open cavity 37 for receiving bearing component 20. Concave shell surface 36 has a diametrical recess 40, and surface 36 is complimentary and approximately the same in contour and radial dimension to convex bearing surface 22. Concave shell surface 36 includes an annular portion 38, which extends beyond its lateral diametrical plane 39.