外踝缺损修复与重建前后力学变化的对比研究

Biomechanical changes of lateral malleolus defect before and after reconstruction

目的测试创伤外踝缺损修复与重建前后的生物力学变化,为临床应用提供理论依据。方法采集12具国人新鲜冰冻下肢足标本,解冻后模拟外科手术,人为造成外踝骨缺损,然后采用第二跖骨底骨瓣重建外踝。实验分组:A组为外踝缺损组;B组为第二跖骨瓣修复外踝组;C组为对照组。建立模型分别进行载荷-应变、载荷-位移、强度、刚度、接触特征等变化的力学测试。结果①1000 N负荷时踝关节载荷-应变及刚度、强度变化,A组与B组相差显著(P<0.05)。②1 000 N负荷时接触特征测量,A组接触面积小于B组(P<0.05),A组接触压力大于B组(P<0.05)。结论外踝缺损可造成踝关节严重失稳,采用第二跖骨底骨瓣修复重建能恢复踝关节的"鞍形"结构和稳定性,是可行的新方法。

Objective To measure biomechanical changes of lateral malleolus defect before and after reconstruction. Methods 12 fresh freezing limb specimens were experimentally tramatized to result in lateral malleolus defect. Three metatarsal base bone flaps repairing lateral malleolus was carried on. Test groups were divided into two groups ： the group of lateral malleolus defect （ group A ） , and the group of lateral malleolus after reconstruction （group B） , and the group of collecting data and doing analysis （ group C）. Modals were built to test out the mechanics changes through loading strain - reaction, loading strain displacement, strength and rigid respectively. Results The change of loading - strain, rigid and strength under 1 000 N showed significant difference between group A and group B（P 〈 0.05 ）. The contact area of group A was less than group B under 1 000 N（P 〈 0.05）. The contact pressure of group A was more than group B （ P 〈 0.05）. Conclusion The defect of lateral malleolus can lead to severe instability of ankle, and can be recovered its stability by using the second metatarsal base bone flap. This is an effective operative method.