BIOMATERIALS FOR ORTHOPEDIC-SURGERY IN OSTEOPOROTIC BONE - A COMPARATIVE-STUDY IN OSTEOPENIC RATS

To evaluate orthopedic devices in pathological bone, an experimental s tudy was performed by implanting Titanium (Ti) and Hydroxyapatite (HA) rods in normal and osteopenic bone. Twenty-four rats were used: 12 we re left intact (Control: C) while the other 12 were ovariectomized (OV X). After 4 months all the animals were submitted to the implant of Ti or HA in the left femoral condyle (Ti-C, HA-C Ti-OVX, HA-OVX). Two mo nths later the animals were sacrificed for histomorphometric, ultrastr uctural and microanalytic studies. Our results show a significant diff erence between the Affinity Index (A.I.) of HA-C and Ti-C (77.0 +/- 7. 4 vs 61.2 +/- 9.7) (p < 0.05). No significant differences were observe d between the osteointegration of Ti-C and Ti-OVX (61.2 +/- 9.7 vs 48. 2 +/- 6.7). Significant differences also exist between the osteointegr ation of HA-C and HA-OVX (77.0 7.4 vs 57.6 +/- 11.5) (p < 0.01). Micro analysis shows some modifications in Sulphur (S) concentration at the bone/biomaterial interface of the Ti-OVX group. Therefore our results confirmed the importance of biomaterials characteristics and of bone q uality in osteointegration processes.