持续应力对松质骨骨折愈合影响的超微结构观察

An ultrastructural observation of the effect of persistent stress on cancellous bone healing

目的观察持续应力下松质骨骨折愈合的细胞超微结构变化，探讨持续应力对松质骨骨折愈合的影响。方法取20只家犬两侧股骨转子部“L”型截骨，左侧以镍钛合金粗隆截骨固定器固定，右侧以钢丝贯穿环扎加压收紧固定。术后2、4、8、12周取材行透射电镜观察。结果镍钛合金粗隆截骨固定器组内固定后骨折愈合时间早于钢丝固定组，且2种不同固定方式下骨折断端间成骨细胞、成软骨细胞及胶原纤维表型及形态均有明显不同，镍钛合金粗隆截骨固定器组细胞及胶原纤维排列表现出明显的同向性，与应力作用方向一致。细胞的增生及胶原的合成也较钢丝组旺盛。结论在镍钛合金转子截骨固定器固定形成的骨折断端间持续应力作用下，松质骨骨折能够获得快速、有效地修复及愈合。

Objective To explore the effect of persistent stress on the uhrastructure of cancellous bone in the process of fracture healing. Method A transverse osteotomy on both sides of the femoral tuberositas was performed in 20 adult dogs. One side was fixed with a self-designed tuberositas memory-pressure connector （TMC） which was made of NiTi shape memory alloy, and the other with compressive steel-wire （SW） cerclage. Five animals in each group were sacrificed at 2, 4, 8, 12 weeks after operation and observed under transmission electron microscope. Results The fracture healing was accelerated in the TMC group. The osteoblasts, choudroblasts and collagen fibers at the fracture sites showed significantly different morphology between the 2 groups at every observation time. Most cells and collagen fibers in the TMC group grew along the same direction as the stress, but those in the SW group grew in disorder. Both the number and functional activity of the osteoblasts and ehondroblasts were higher in the TMC group than in the SW group. Conclusion Persistent stress can enhance healing and bone reconstruction following a cancellous bone fracture.