Effect of Hydroxyapatite Interposed Between Bone and Bone Cement in Total Hip Arthroplasty on Long Term Longevity ----19 to 20 Year Radiographic Studies on Using and Without Using of HA in the Same Patients

THAs were performed with conventional cementing on one side (1985 to 1986) and with modified cementing using HA granules on the other side (1986) of the same patients. Both hips were compared 19 to 20 years after surgery. In IBBC, there was no loosening, radiolucent line (RLL) < 1 mm was in one acetabulum and osteolysis was in one femur. In conventional cementing three hips were revised within 18 years in five acetabular loosenings. RLL > 2 mm and osteolysis were defined in every patients in both femur and acetabulaum.