股骨粗隆间骨折滑动加压外固定器的设计及步态模拟实验结果分析

Walking Model Experiment and Study of Sliding Load External Fixator (SLEF) in Fixture of Intertrochanteric Fracture

目的在单侧成角度外固定器和动力髋螺钉(DHS)的基础上设计制作股骨粗隆间骨折滑动加压外固定器,并对其生物力学性能进行评价。方法取5对成人新鲜股骨标本,造成AO分型A1.1型股骨粗隆间骨折模型。实验组用滑动加压外固定器固定,对照组用单侧成角度外固定器固定。实验在电子万能实验机上进行加载,YD-15型动态电阻应变仪记录结果,载荷范围设为0～800N。结果对照组1个步态周期内出现1个峰值,而实验组出现3个应变峰值和2个最小值,这种应变峰值和最小值的反复出现使骨折两端产生轴向微动,最终发生嵌插,骨折断端相对稳定。实验组最大应变值明显高于对照组,并且对照组应力集中在股骨距处而实验组应力以滑动螺钉为中心分布,这有利于骨折愈合。结论滑动加压外固定器具有滑动、加压双重功能,它可以在步态周期的不同阶段提供相应的生物力学支持,具有固定可靠、能避免或减少髋内翻等并发症、促进骨折愈合等优点。

Objective To design and make sliding load external fixator （SLEF） aeeorcling to unilateral angulated external fixator and dynamic hip serew, and evaluate its biomechanical properties. Methods Five pairs of fresher adult femur specimens were prepared,after t he model of A1.1 （AO classification） fracture was established. The specimens in the experimental group were fixed with sliding load external fixation （SLEF） while the specimens in the control group were fixed with traditional one arm external fixation. The specimens were loaded on electronic almighty experimental plane. The consequence was reeorded by YD-15type dynamic electric resistanee deformeter. The load was 0-800N. Results In a walking cycle ,the emergence of a peak in the control group, and three test contingency peaks and two minimum in the experimental group , and this facilitated the healing of fractures. Conclusion The sliding load external fixator （SLEF） has double funetions of sliding and load. It can avoid eoxa vara and other eoInplieations, and promote union of fracture.