REMODELING OF BONE AROUND HYDROXYAPATITE AND TITANIUM IN EXPERIMENTAL OSTEOPOROSIS

The affinity of the tibia bone for cylinders of hydroxyapatite (HA) and Ti-6Al-4V was investigated in three experimental animal models: intact rat tibiae, ovariectomized rat tibiae and ovariectomized plus neurectomized rat tibiae. The affinity index (the length of bone directly apposed to the implant/the total length of the bone-implant interface x 100%) was calculated. In intact and ovariectomized tibiae, no significant difference existed between the affinity index of HA and Ti-6Al-4V. In ovariectomized plus neurectomized tibiae, the affinity index of HA was greater than for Ti-6Al-4V from 8 to 24 wk after implantation (8 wk, P < 0.05; 12 wk, P < 0.005; 24 wk, P < 0.05). The affinity index of Ti-6Al-4V in normal tibiae was greater than that in ovariectomized or ovariectomized plus neurectomized tibiae. There was no significant difference of the affinity index of HA between normal, ovariectomized or ovariectomized plus neurectomized tibiae. Osteoporotic bone demonstrated a greater affinity to HA than Ti-6Al-4V in an experimental animal model.