Abstract: Objective　 To investigate the effects of osteoporosis on stability of titanium implants with completed bone integration. Methods　60 female rats were submitted to a titanium implant at the femoral knee. After a healing period of 8 weeks, the animals were randomly divided into two groups: sham-operated group(30 animals) and operation group(30 animals). The SHAM group was submitted to fictitious surgery and the operation group was submitted to bilateral ovariectomy. 3,6 and 12 weeks after surgeon, 10 rats of both the SHAM and operation groups were sacrificed. In order to confirm the bone structure alter in rats, the Micro-CT analysis, histological observation and also the biomechanical test were performed to measure the effect on the stability of implants. Results　 There was no significant difference in Sham-group between the three time points（p>0.05）. While by the time passing by, the test results of operation group showed that bone volume fraction, bone connectivity density, trabecular thickness and number decreased , but increased in trabecular spacing in the micro-CT analysis（P<0.05）. And the percentage of osseointegration of operation group decreased too（P<0.01）. The slices showed that the peri-implant bone tissues were absorbed, while the trabecular of fermur became osteoporotic after ovary removal. With time passing by, the Fmaxwere got lower too. Conclusions　 The present study shows a bone resorption in the region of bone around titanium implants and a decrease of the percentage of osseointegration after ovary removal. These changes finally result in the decrease of stability of integrated implant.

Key words: osteoporosis, implant, osseointegration, stabilityt