Use of irradiated bone graft for impaction grafting in acetabular revision surgery: a review of fifty consecutive cases.

Impaction bone grafting is a useful technique in the armament of a revision hip surgeon. Traditionally fresh frozen allograft has been used for this technique. However there are concerns about the transmission of viral proteins and prions through this form of allograft. As a result irradiated bone graft has been favoured in some centres. There is no long term series describing the results of impaction bone grafting using irradiated bone. This paper reviews a consecutive series of 50 cases of acetabular revision surgery performed between 1995 and 2001 and followed up over a mean period of 45 months. The preoperative bone defect was graded by the Paprosky classification. There were 2 cases of type 1a, 9 type 2a, 15 type 2b, 7 type 2c, 10 type 3a and 7 type 3b. All cases were followed up clinically and radiologically. Case notes were reviewed for primary prosthesis, operative details and reason for revision. The radiographs were evaluated for signs of bone incorporation, remodelling, loosening and migration of the acetabular component. There were 5 cases of aseptic loosening at the end of the follow up period. One patient had recurrent dislocation and was revised. 20 cases (40%) showed changes suggestive of bone incorporation, while only 3 cases (6%) showed remodelling. Clinically a good or excellent outcome with absence of pain was achieved in 35 patients (70%). The results suggested that acetabular impaction bone grafting using irradiated bone graft is comparable to fresh frozen allograft. The low percentage of remodelling remains a concern and warrants further studies.