MEDIUM TERM RESULTS OF IMPACTION GRAFTING OF ACETABULAR DEFECTS WITH IRRADIATED ALLOGRAFT BONE

Abstract

Allograft bone is commonly used to reconstruct areas of bone loss around failed total hip replacements. Irradiated allograft bone may help to reduce the risk of transmission of infectious agents from donor to recipient. The purpose of this study was to establish the results of impaction bone grafting of acetabular defects using frozen, irradiated allograft bone. All patients treated by a single surgeon with impaction bone grafting of acetabular defects at revision total hip replacement were reviewed retrospectively. All operations were performed during the period 1994-2000. The mean followup was 50months (range 30-96months). Case notes and Xrays were reviewed and analysed. The Paprosky grade of acetabular defects was determined from the pre-operative Xrays and the surgeon’s note at the time of operation. Postoperative Xrays were reviewed to establish the extent and rate of new bone ingrowth. Functional outcomes were determined by way of selfadministered questionnaires. 46 patients were identified as fulfilling the inclusion criteria for the study. Six had died and seven had incomplete records. Complete records and Xrays were obtained for 33 patients who underwent revision hip arthroplasty with impaction bone grafting of the acetabulum using frozen, irradiated bone. There were 21 patients with a previously uncemented acetabular component and 12 with a cemented component. The Paprosky classifications of the defects were as follows: 3 type 1, 10 type 2A, 4 type 2B, 4 type 2C, 10 type 3A and 2 type 3B. Titanium mesh and/or a reinforcement ring were used in all cases of uncontained acetabular defects. There were no complications associated with the bone grafts and no patient required reoperation. Review of serial Xrays confirmed ingrowth of host bone. The functional results obtained were as follows: 17 patients (52%) could walk an unlimited distance. 11 patients (33%) required no walking aids whilst a further 17 (52%) required a single cane to mobilise. 21 patients (64%) were able to use public transport after the operation. 20 patients (61%) reported little or no pain. 9 patients (28%) had no limp and 14 patients (42%) had a slight limp. Overall 29 patients (88%) declared themselves to be satisfied with the outcome of their surgery. 32 patients (97%) improved functionally after their operation. These results indicate that satisfactory results can be achieved with impaction bone grafting using frozen, irradiated allograft bone. The use of irradiated bone graft can potentially reduce the risks of disease transmission from donor to recipient without compromising the surgical results.