A, Cavitary deficiencies (arrows) in 42-year-old postal worker with groin pain 13 years after bipolar hemiarthroplasty. Polyethylene wear has produced large superior and medial cavitary deficiencies. B, Defects were filled with cancellous allograft with placement of porous revision implant. Hip center accurately restored. C, At 4 years, bone grafts have remodeled and appearance is that of a primary arthroplasty. SEE TECHNIQUE 3.23.