The effect of hydroxyapatite on bone ingrowth into porous-coated titanium implants.

Two different groups of hydroxyapatite (HA) coated and uncoated porous titanium implants, 250-350 m and 500-700 m diameter beads, were press-fit in femoral canine cancellous bone. After 12 weeks, the dogs were euthanized and histomorphometric backscattered electron microscopy studies were carried out. Comparing HA-coated versus uncoated implants in the 250-350 m bead diameter group percentage of bone (P=0.01) and bone index (P=0.01), were higher in the HA-coated implants. Comparing HA-coated versus uncoated implants in the 500-700 m bead diameter group bone ingrowth (P=0.01) and bone depth penetration (P=0.008), were higher in HA-coated samples. It can be concluded that the HA coating was an effective method to improve bone formation and ingrowth in the porous implants. (Hip International 2002; 2: 153-7).