长骨干骨痂延长骨愈合成骨方式实验研究

Experimental investigation on callotasis osteogenesis of long bone

目的 探讨长骨干骨痂延长骨愈合的成骨方式及其细胞学机制。方法 健康成年山羊 10只 ,左胫骨中段骨膜下横形截骨 ,以四环式外固定架固定。 2周后作骨延长 ,每日延长 1mm ,连续 30天。延长开始至延长结束后 16周分期处死动物取材 ,以X线摄片、光镜及电镜作连续观察。结果 骨延长开始时 ,骨外膜侧已有小梁骨形成 ,纤维组织呈纵向排列 ,与牵拉方向一致 ;成纤维细胞合成 ,分泌大量胶原纤丝。早期骨形成始于骨外膜侧及两截骨端 ,逐渐向纤维组织深入。骨延长结束后 ,纤维组织最终为成熟骨组织所替代。电镜观察显示上述新骨形成和改建活动均有成纤维细胞的参与。结论 长骨干骨痂延长骨愈合过程主要通过膜内骨化方式完成 。

Objective To investigate the process and its cellular mechanism of new bone formation of callotasis of long bone. Methods Ten adult goats were used in the experiment. Subperiosteal transverse osteotomies were performed on the mid shaft of left tibiae which were fixed with four ring Illizarov external fixator. After 2 week's delay, the tibia was lengthened 1 mm per day for 30 days and radiography was taken every week postoperatively. The sheep were sacrificed for light microscopic and transmission electron microscopic observation at the begining, and 7, 14 and 30 days of distraction, and at 1, 2, 4, 8, 12 and 16 weeks after the completion of distraction. Results Slender bone trabeculae was formed at the periosteal side in the early stage of distraction while the distraction gap was first filled with fibrous tissue. As the distraction process continued, the fibrous tissue became longitudinally arranged in direction of elongation, the fibroblasts synthesized and secreted plenty of collagen fibrils. Early bone formation extended from the periosteal side and the distracted bone edges into the fibrous tissue, which was eventually transformed to mature cortical bone after the completion of distraction. The fibroblasts participated in the process of new bone formation and remodelling during and after distraction. Conclusion Bone formation of callotasis of long bone is predominantly by intramembranous ossification, in which the fibroblasts may play an important role.