Hydroxyapatite Granules in Acetabular Reconstruction

Freeze-preserved allografts have been used in cases of massive bone deficiencies during revision total hip arthroplasty. Excellent results have been reported in Europe and in the USA (1-4). Cases using allografts have also been reported in Japan (5), although in Japan materials other than femoral heads, partial femoral condyles and partial tibial plateaus from patients undergoing arthroplasty are still very difficult to obtain. However, increasing interest in bioactive ceramics, particularly in hydroxyapatite (HA) over the past 15 years, has resulted in a significant increase in its clinical application during this period (6-14). Under these circumstances, we began to use sintered HA granules clinically. As a material, sintered HA is not resorbable, binds to the bone physicochemically, and is strong enough as a bone defect filler. We obtained good results in three revision cases by placing fine HA granules (300-500!Jm) between the bone cement and the bone graft on the deficiencies of the femur in 1984 (Oonishi et al., 1991). In addition, since 1985 massive bone deficiencies have been filled with HA granules (9, 10, 11, 12).