天鹅型记忆接骨器对犬股骨骨折愈合的影响

目的：探讨天鹅型记忆接骨器（SMC）内固定对骨折愈合的影响及其机制。方法：25条家犬两侧股骨中段横型载骨，左侧以SMC内固定（SMC组），右侧以加压接骨钢反（CP组）内固定，术后1、2、4、8、12周行X线摄片、三点折弯测试、骨组织形态测量观察。结果：X线显示在SMC组术后4周骨折愈合，CP组在8周，SMC组愈合过程中未见明显的外骨痂及骨质疏松，骨折后4、8、12周，SMC组骨痂内骨生成量、截骨处骨皮质厚度和固定段骨力学强度均高于CP组（P＜0．05）。结论：与CP比较，SMC内固定可对骨折起到有效内固定和持续加压作用，使骨愈合时间缩短，提高了固定段骨的力学强度。

Effects of swan-like memory compressive connector on healing of femoral fractures in dogs

Objective:To investigate the influence and mechanism of swan like memory compressive connector(SMC) made of Ni Ti shape memory alloy on fracture healing. Methods:Bilateral femoral of 25 adult dogs were osteotomized in the middle and fixed with SMC(SMC group) on left sides, compression plates(CP group) were plated on the right sides. Five animals in each group were sacrificed at 1,2,4,8,12 weeks after operation and observed under X rays examination, histomorphologic study and biomechanical test. Results:The process of fracture healing was accelerated with SMC fixation, and no external callus and osteoporosis were observed in experiment group. The mechanical properties of fixed bone, the amounts of new bone and the cortex thickness of fracture fragments in SMC group were higher than those of CP group 4 12 weeks after operation. Statistical significant difference was found between SMC group and CP group( P <0.05). Conclusion:Fracture fixation with SMC has stability and the continued axial stress, these characteristics of SMC is beneficial to fracture healing and the mechanical property of the fixed bone.