弹性固定修复Lisfranc韧带损伤的有限元分析

Finite element analysis on flexible fixation for ligamentous Lisfranc injuries

[目的]研究弹性固定方式修复Lisfranc韧带损伤的关节稳定性,并比较空心钉固定的优劣,为临床正确的选择重建方案提供理论依据。[方法]选取健康男性志愿者的足部三维CT图像,利用Mimics16.0、Geomagic、Cero4.0分别建立正常对照、Liafranc韧带损伤、弹性重建和空心钉重建4个足部三维模型。计算轴向载荷下,C1-M2间的总位移量、横向位移量、纵向位移量。[结果]空心钉重建模型的总位移量显著小于弹性重建模型和正常模型,差异有显著统计学意义(P<0.05)。弹性重建模型总位移量在中立位时和正常模型相似,差异无统计学意义(P>0.05),但在跖屈30°位,弹性重建模型总位移量大于正常模型,差异有统计学意义(P<0.05)。空心钉重建模型的纵向位移量显著小于弹性重建模型和正常模型,差异有显著统计学意义(P<0.05)。弹性重建模型横向位移量和正常模型比较,差异无统计学意义(P>0.05)。[结论]弹性固定修复Lisfranc韧带能够为跖跗关节损伤后韧带和关节囊愈合提供良好的力学环境,有效避免空心钉固定的并发症。

[Objective]To study the stability of flexible fixation for ligamentous Lisfranc injuries,and to provide theoretical basis for clinical choice.[Methods]Three-dimensional CT images of feet of healthy male volunteers were selected.Four threedimensional models of feet were established by Mimics 16.0,Geomagic and Cero 4.0,respectively,including normal model,Liafranc ligament injury model,flexible fixation model and cannulated screw fixation model.The total displacement,transverse displacement and longitudinal displacement between C1 and M2 under axial load were calculated.[Results]The total displacement of the cannulated screw was significantly less than that of the flexible fixation model and the normal model(P<0.05).In addition,the total displacement of the flexible fixation model was similar to that of the normal model in the neutral position(P>0.05),whereas at the plantar flexion 30 degree,the total displacement of the flexible fixation model was significantly greater than that of the normal model(P<0.05).The longitudinal displacement of the cannulated screw model was significantly less than that of the flexible fixation model and the normal model(P<0.05).The lateral displacement of the flexible fixation model was similar to that of the normal model in neutral position(P>0.05).[Conclusion]Flexible fixation for ligamentous Lisfranc injuries could provide a stable mechanical environment for the healing of ligament and joint capsule,which should be used in patients with intact second metatarsal and medial cuneiform.