A kit and a method for implanting a prosthetic acetabular cup in an acetabular has a prosthetic acetabular cup having an open end for receiving a head of a prosthetic femoral component. The cup has a flange extending outwardly from a surface thereof adjacent the open end. The flange is angled toward the acetabulum. The acetabulum is prepared to receive the prosthetic acetabular cup, the preparation includes forming a circumferential rim shaped seat in the bone around the acetabulum. The cup flange has a maximum diameter less than the outer diameter of the circumferential rim.