Prosthetic acetabular cup and prosthetic femoral joint incorporating such a cup

A prosthetic acetabular cup for implantation in an opening of the acetabulum, the acetabulum having a rim extending between the pubis and the ischium through the illium, comprising:

• an outer member having an outer surface for engaging and configured to be affixed to the acetabulum, said outer member having a part-spherical inner bearing surface, the outer member extending about a polar axis terminating in a 360° circumferential distal rim surrounding the opening of the acetabulum, the rim having a generally inferiorly facing edge surface, the polar axis is perpendicular to a plane containing the rim of the acetabulum, said generally inferiorly facing edge surface of the rim of the outer member having a contour continuously curved in the generally inferior-superior direction around the entire circumference of the rim with the generally inferiorly facing edge surface moving toward and away from the plane of the acetabular rim two times such that a portion of the generally inferiorly facing edge surface of the rim to be located between the ischium and the pubis extends further towards a polar region of the bearing surface, where the polar axis intersects the bearing surface than a contour portion of the generally inferiorly facing edge surface of the rim to be implanted between the pubis and the illium and a generally inferiorly facing edge surface contour portion to be implanted between the ischium and the illium and a contour portion of the generally inferiorly facing edge surface of the rim to be implanted between the pubis and the illium extends distally further from the polar region than the contour of the generally inferiorly facing edge surface of the rim between the ischium and the illium, wherein the contours of the outer edge of the rim to be implanted at the ischium and the illium are closer to the polar region than the remainder of the rim.