下胫腓联合损伤模型复位的压力与位移变化的生物力学研究

Biomechanical study on the changes of pressure and displacement in the different tibiofibular syndesmosis injury model

目的探讨下胫腓联合损伤复位施加压力与位移变化的关系,探索最佳复位力度。方法选取10例新鲜冻融尸体小腿标本,解剖下胫腓联合复合体,依次切断下胫腓联合前方结构(下胫腓前韧带)、后方结构(下胫腓后韧带和下胫腓横韧带),以及下胫腓联合上方10 cm的骨间膜,在同一标本上建立不同程度的下胫腓损伤模型,每个模型分别接受CT扫描,通过Mimics软件测量外踝嵴(A)和内踝表面中心(B)在不同模型中的距离。循AB连线方向复位,记录位移与压力大小的关系。结果分别切断下胫腓前联合、前后联合、前后联合及上方10 cm骨间膜后,AB平均距离均有增大,与下胫腓联合完整时差异有统计学意义,P<0.05;但每组损伤模型间AB距离对比无明显统计学差异,P>0.05。使用生物力学压力测试仪测出下胫腓解剖复位所需压力为40～70 N。下胫腓前后联合断裂复位所用压力与单纯下胫腓前联合断裂复位对比差异无统计学意义,P>0.05。下胫腓前后联合及上方10 cm骨间膜断裂复位所用压力与下胫腓前后联合断裂复位对比差异无统计学意义,P>0.05;但与单纯下胫腓联合前韧带断裂复位对比差异具有统计学意义,P<0.05。结论下胫腓联合不同程度损伤后,下胫腓之间分离的距离较完整时存在显著性差异,需用不同大小的力量进行复位。

Objective To explore the relationship between the reduction pressure and displacement after the tibiofibular syndesmosis injury and find out the best reduction force. Methods Ten fresh frozenthawed calf specimens were selected. The tibiofibular syndesmosis was exposed. then the anterior structures(anterior tibiofibular ligament), posterior structures including the posterior tibiofibular ligament, the transverse tibiofibular ligament, and the interosseous membrane 10 cm proximally were dissected respectively. Each model underwent CT scans, and the distances from the point A on the lateral malleolus ridge to the point B on the center of the medial tibia were then measured. Meanwhile, the reduction was performed and the relationship between distance and pressure was recorded. Results The Mimics software was used to measure the distance of AB in different models. After disruption of the anterior tibiofibular syndesmosis,anteroposterior tibiofibular syndesmoses, anteroposterior tibiofibular syndesmoses combined with the interosseous membrane 10 cm proximally, the average distance of AB increased significantly compared with that with the intact tibiofibular syndesmosis(P<0.05), but the corresponding distances between each model were not statistically significant(P>0.05). Using the biomechanical stress tester, the magnitude of stress was detected to be 40~70 N. There was no significant difference in the magnitude of the restoring force between anterior tibiofibular syndesmosis and anteroposterior tibiofibular syndesmoses injury models(P>0.05). There was no significant difference in the magnitude of the restoring force between anteroposterior tibiofibular syndesmoses and anteroposterior tibiofibular syndesmoses combined with the interosseous membrane 10 cm proximally injury models(P>0.05), but there was a significant difference in the magnitude of the restoring force between anterior tibiofibular syndesmosis and anteroposterior tibiofibular syndesmoses combined with the interosseous membrane 10 cm proximally injury models(P<0.05). Conclusions In different degree of tibiofibular syndesmosis injuries, there is a significant difference in the deviation distance of the tibiofibular syndesmosis, and different forces must be chosen to reduce the different stages of tibiofibular syndesmosis displacement.