Fig. 4.

The DMC design was improved by medialization of the PE cup. The center of rotation of the surface bearing of the metal socket is more medial than the center of the socket periphery. Therefore, resultant forces acting on the PE cup avert its tilting in varus (and thus the risk of upper PE cup rim wear, leading to subluxation). To reduce the wear of the entire rim, the head:neck ratio is 22 mm:10 mm, which allows more than 25° of abduction or rotation in the inner articulation. The femoral neck is polished, and its good congruity with the PE rim limits chipping during impingement.