Loosening of acetabular components causes loss of bone stock secondary to polyethylene wear. There are several types of bone loss that give certain radiographic presentations. Each bone loss type requires a specific type of reconstruction employing different bone grafting techniques. Superior migration of the acetabular component greater than 2-3 cm in combination with severe posterior rim loss manifested as severe ischial lysis on x-ray film indicates a need for support allograft to achieve stability since greater than 30% of the cup will not be supported by host bone.If the inner table of the medial acetabulum is violated as well, then over 60% of the component is not in contact with host bone. Biologic fixation of the cup is unlikely in these instances and a whole acetabular graft with cemented component is needed. Of the 316 acetabular revisions performed from 1982—1991 with a mean follow-up of 5.1 years, 69 required support allograft or whole acetabular grafts. In the remaining cases, only cancellous bone was used to fill defects since the rim was supportive. There was less than 2 cm of superior migration of the component and only minimal ischial and medial bone loss. A maximum of 30% of the porous surface of the cup was not in contact with host bone.