John Birkedal, MD; Douglas Kilgus, MD
Retroacetabular osteolysis is a significant problem in total hip arthroplasty. Clinical, radiographic, and histologic data have linked particulate debris from component wear to progressive bone loss, loosening, and eventual failure of the implant.1-3 Not only does this osteolysis result in eventual failure of the implant, but also it provides considerable technical difficulty during revision surgery. Obtaining a stable platform for the revision acetabular component is dependent on the quality of the remaining bone and the location and the severity of the bone loss. Many classification systems have been proposed for characterizing acetabular bone loss.4 These include those proposed by Chandler and Penenberg,5 Paproski and associates,6,7 Engh and Glassmann,8,9 and D’Antonio and associates.10 The classification system of D’Antonio and associates has been recommended by the American Academy of Orthopedic Surgeons (AAOS) and is shown in the Table.