ABSTRACT
The concept of surface arthroplasty (SA) of the hip has always been appealing because of its conservative nature and adherence to the basic principle of replacing only diseased bone. These principles date back to SmithPetersen’s initial mold arthroplasty of the hip that, however, was not fixed to the bone (1). Haboush was the first to implant a surface type arthroplasty of the hip using a metal-on-metal bearing as well as acrylic cement to fix the prosthesis to the bone (2). Later on, Charnley experimented with the same concept using two concentric shells made out of polytetrafluroethylene (3), but he abandoned it because of the concern of ischemic necrosis of the femoral head remnant as well as the higher frictional torque of the larger head sizes (4). Despite this, in the early 1970s, investigators from different countries developed several designs that initially showed encouraging results (5-9) and appeared a promising alternative to total hip replacement (THR) for the young patient. Unfortunately, this was not the case, and failure rates of 15-33% were reported by multiple centers at a mean follow-up of 3 years (10-12). Also, when socket loosening occurred, some centers reported major acetabular defects at conversion surgery (13-15).
