【摘要】 目的:探讨天鹅型形状记忆接骨器固定下骨折愈合时应力遮挡率随时间的变化以及骨折处超微结构和力学性能的特点。方法:新西兰兔行单侧肱骨干横断截骨,实验组以天鹅记忆接骨器内固定,对照组以加压钢板固定。分别于术后第2、4、8、12、16周时取材,测定应力遮挡率和愈合骨的生物力学性能,并观察骨折端的超微结构变化。结果:愈合过程的前12周内实验组的应力遮挡率明显较低而力学性能则高于对照组,电镜观察则显示实验组矿物质沉积领先于对照组且胶原纤维排列整齐。结论:天鹅记忆接骨器应力遮挡效应较小,加快了成骨细胞的分化成熟,促进了骨痂细胞外基质的生成和钙化,从而提高了愈合骨的力学性能。更多还原

【Abstract】 Objective:To investigate the stress shielding rate,ultrastructural and biomechanical property of the healing bone fixed by Swan like Shape Memory Connector(SMC) during experimental fracture healing in rabbits.Methods:Unilateral osteotomy of left humeral diaphysis was performed in 140 adult New Zealand rabbits.The humeral fracture was fixed with SMC in study group and 4 hole dynamic compression plate(DCP)in control group.The animals were sacrificed at the 2nd,4th,8th,12th,and 16th weeks postoperatively.The humeral shafts were harvested for three point bending tests and stress shielding rate examination.Samples from the fracture gaps were observed with scanning electron microscope.Results:Within an observation period of 12 weeks after operation,the stress shielding rates were significantly lower in study group than those in control group,and the bending strength and the bending rigidity were statistically higher.It was also found that collagen fibers in callus was arranged more regulate and early mineral deposition in study group.Conclusion:These results suggest that SMC contributes to the proliferation and differentiation of osteoblasts,promoting the formation and calcification of bone matrix and enhancing biomechanical property of the healing bone,which might be closely correlated with a less stress shielding effect produced by SMC.更多还原