Abstract: The invention pertains to a method and apparatus for enhancing the depth of the acetabulum to improve the containment of the femoral head, and the concepts of the invention are employed to correct an unstable hip joint, particularly as occurs with children. A synthetic extracapsular curvalinear prosthesis is affixed to the ilium by fasteners and the prosthesis includes a concave surface corresponding to the configuration of the acetabular socket wherein the prosthesis increases the depth of the acetabulum without disturbing the existing anatomy.