骨质疏松对完成骨整合的大鼠股骨钛种植体稳定性的影响

Effects of osteoporosis on stability of osseointegrated implants

目的研究骨质疏松对已完成骨整合种植体的稳定性的影响。方法在雌性Wistar大鼠股骨远端干骺端植入纯钛种植体,经过8周愈合期后随机分组,Sham组(30只)施行假手术,手术组(30只)施行双侧卵巢摘除术,于术后3周、6周、12周收集带种植体的股骨标本进行Micro-CT扫描分析、组织学观察及生物力学实验,评估OP对种植体周围骨组织及其稳定性的影响。结果 Sham组各时间点测量结果未见显著差异(P>0.05),而手术组Micro-CT扫描分析测得的骨小梁数目和厚度,骨组织体积比均随时间的增加而明显下降,骨小梁间隙则明显增高(P<0.05),手术组骨整合率也随时间增加明显减低(P<0.01)。组织学观察示手术组种植体周围骨小梁和致密骨质层随时间的增加,骨质吸收逐渐加重。手术组测得种植体的最大拔出力随时间增加明显减低(P<0.05)。结论骨质疏松的发生,会使已完成骨整合的钛种植体周围骨小梁和致密骨质层发生骨质吸收,降低骨整合率,导致种植体稳定性减低。

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（ P0.05）. 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（ P0.05）. And the percentage of osseointegration of operation group decreased too（ P0.01）.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.