To augment cement-bone bonding, hydroxyapatite (HA) granules were interposed at cement-bone interface (IBBC technique). HA granules were smeared on the bone surface just before cementing components. Porous HA granules of 300 to 500μm in diameter and 100 to 300μm in diameter were used from 1986 to 1988(first generation) and 1989 to 1991(second generation), respectively. 222 hips of 151 patients in the first generation and 252 hips of 170 patients in second generation could be followed. After 16 to 21 year follow up, radiolucent line (space), less than 1mm, was observed in 4 hips(1.8%) in the first generation and in 15 hips(6.2%) in the second generation(p<0.01). osteolysis was observed in 1 hip(0.5%) and 6 hips (1.6%), respectively. Loosening (separation) was observed only 2 cups (0.8%) in the second generation.