Biomaterials for orthopedic surgery in osteoporotic bone: A comparative study in osteopenic rats

To evaluate orthopedic devices in pathological bone, an experimental study was performed by implanting Titanium (Ti) and Hydroxyapatite (HA) rods in normal and osteopenic bone. Twenty-four rats were used: 12 were left intact (Control: C) while the other 12 were ovariectomized (OVX). 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 months later the animals were sacrificed for histomorphometric, ultrastructural and microanalytic studies. Our results show a significant difference 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 observed between the osteointegration of Ti-C and Ti-OVX (61.2 +/- 9.7 vs 48.2 +/- 6.7). Significant differences also exist between the osteointegration of HA-C and HA-OVX (77.0 7.4 vs 57.6 +/- 11.5) (p < 0.01). Microanalysis 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 quality in osteointegration processes.