To evaluate the results of acetabular reconstruction using block bone graft in primary cementless total hip arthroplasty (THA).

Twenty-four primary THA, in which a block bone graft was used for the reconstruction of the acetabular bone defect, were performed between May 1989 and July 1999, and followed for more than 2 years. Clinical results were assessed using the Harriship score. Radiologically, we observed the graft coverage of the acetabular component, union, resorption of the graft, change in the positionof the hip center, linear wear rate of the polyethylene insert, osteolysis around the acetabulum and evidence of loosening of the acetabularcomponent.

The mean Harris hip score improved from 65 points preoperatively to 86 points postoperatively. The coverage of the acetabular components by graft was less than 50% in all hips. Union of the grafted bone took 8 months (5-15 months) on average. During the follow-up period, revisions were required in 3 hips (12%). The causes of the revision were osteolysis.

Non-structural block bone grafting seems to be a reliable method for restoring acetabular bone stock in primary THA usinga cementless acetabular component.