Egger E L, Gottsauner-Wolf F, Palmer J, Aro H T, Chao E Y
Department of Orthopedics, Mayo Clinic/Mayo Foundation, Rochester, Minnesota 55905.
J Trauma. 1993 Feb;34(2):185-92. doi: 10.1097/00005373-199302000-00001.
The effects of early dynamization (physiologic axial compression) on canine fracture healing at six weeks were studied. Bilateral transverse mid-tibial osteotomies were created and initially stabilized with a 2-mm gap using relatively rigid external fixators. Seven days after osteotomy, the telescoping mechanism of one of the fixators on each dog was released (dynamized), resulting in physiologic loading of the osteotomy, while the contralateral fixator remained locked as a rigid control. The dynamized osteotomy closed, and increased functional weight bearing resulted from 3 weeks on. Radiographically the amount of periosteal callus increased over time, but no difference in callus size was seen between the dynamized fractures and the controls. Torsional mechanical testing found the dynamized osteotomies to be significantly stiffer, and they tended to tolerate more maximum torque than the controls. Microscopic evaluation found no difference in the volume of the periosteal and endosteal calluses or in the tissues constituting them. However, a significantly greater proportion of the dynamized osteotomy gap was filled with new bone. These results suggest that dynamization in this delayed union model improved fracture healing by reducing fracture gap size and increasing weight bearing, not by altering the pathway of fracture healing.
研究了早期动力化（生理性轴向压缩）对犬六周时骨折愈合的影响。制作双侧胫骨中段横行截骨，并最初使用相对刚性的外固定器以2毫米间隙进行稳定固定。截骨术后7天，每只犬一侧固定器的伸缩机制被释放（动力化），导致截骨部位承受生理性负荷，而对侧固定器保持锁定作为刚性对照。动力化的截骨部位闭合，从3周开始负重功能增加。放射学检查显示，骨膜骨痂量随时间增加，但动力化骨折与对照骨折之间骨痂大小无差异。扭转力学测试发现，动力化的截骨部位明显更坚硬，并且它们比对照部位倾向于耐受更大的最大扭矩。显微镜评估发现，骨膜和骨髓内骨痂的体积或构成它们的组织没有差异。然而，动力化截骨间隙中有明显更大比例被新骨填充。这些结果表明，在这种延迟愈合模型中，动力化通过减小骨折间隙大小和增加负重来改善骨折愈合，而不是通过改变骨折愈合途径。
