Excellent Bone Ingrowth into HA Granules Filled in Acetabular Massive Bone Defect under Weight Bearing Condition

Abstract

We have used HA granules in acetabular massive bone defect in revision THA since 1985. Because as HA is osteoconductive and crystal HA is not resorbable, new bone formation will continue forever. In clinical cases, porous HA granules were filled densely into massive acetabular bone defects under weight bearing condition. Whole HA granule masses of approximately 2.0 and 2.5 cm in thickness were retrieved at revision THA. Non-decalcified specimens were observed. As a control, in non-weight bearing condition, HA granules were filled densely into the cavity made at the proximal end of the tibia of mature goats. At one year and six months the goat was sacrificed. It was very difficult to drill into the HA granule mass and to cut the mass with a chisel. A large amount of bone ingrowth from the acetabulum were found in the whole spaces. In a control a large amount of bone ingrowth were obtained into the spaces only at the peripheral area of the cavity to approximately 5 mm in depth. A large amount of bone growth to the deep area can be expected in weight bearing areas. However, in non-weight bearing areas, it can't be expected.