REMODELING OF BONE AROUND HYDROXYAPATITE AND TITANIUM IN EXPERIMENTALOSTEOPOROSIS

The affinity of the tibia bone for cylinders of hydroxyapatite (HA) an d Ti-6Al-4V was investigated in three experimental animal models: inta ct rat tibiae, ovariectomized rat tibiae and ovariectomized plus neure ctomized rat tibiae. The affinity index (the length of bone directly a pposed to the implant/the total length of the bone-implant interface x 100%) was calculated. In intact and ovariectomized tibiae, no signifi cant difference existed between the affinity index of HA and Ti-6Al-4V . In ovariectomized plus neurectomized tibiae, the affinity index of H A 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 demonst rated a greater affinity to HA than Ti-6Al-4V in an experimental anima l model.