Elliptic acetabular component for a hip prothesis

A hip cup for use as an acetabular component in a hip prosthesis of a patient having a bone cavity including an inner surface configured as a segment of spherical surface and which includes a peripheral portion, said cup comprising an outer shell having a partially convex outer surface and a circumferential edge portion and having an apex and a central cross-section and forming one half of an ellipse with a short radius through the apex and a long radius at the peripheral portion, the outer shell being configured for insertion into the bone cavity,

• said circumferential edge portion of the outer surface of the outer shell upon insertion into said cavity contacts said peripheral portion of the cavity and is configured to form a space between the inner surface of the cavity and the apex of the outer shell, said outer surface of the outer shell being defined by rotation of said ellipse about said short radius and having a cross section in a plane containing the long radius of the ellipse to form a half rotational ellipsoid,
• the ratio between the length of the short radius between said apex and said long radius and the length of the long radius within the ellipse is approximately between 0.9 and 0.975.