不同位置腓骨截骨后踝关节力学改变的有限元分析

Finite-element analysis of mechanical changes of ankle joint after peroneal osteotomy in different positions

目的基于有限元分析探讨不同高度腓骨截骨后的力学变化及对踝关节的影响,为腓骨移植修复下颌骨缺损选择合适的腓骨截骨位置提供理论指导。方法纳入2020年6月—2022年6月蚌埠医学院第一附属医院CT室10例患者的左下肢CT影像资料,其中男7例、女3例,年龄20~60岁、中位年龄43岁,口腔癌患者4例、右下肢骨折患者6例。基于患者CT扫描原始数据,采用Mimics、Geomagic studio、SolidWorks、Abaqus等软件构建出包含胫腓骨和踝关节的三维有限元模型。按照腓骨截骨高度不同分为5组:A组(对照组)为包含完整的胫腓骨和踝关节的骨骼模型,B组~E组(观察组)分别为距离腓骨下端5、7、9和11 cm处向上截取8 cm长腓骨的胫腓骨和踝关节骨骼模型。在有限元分析软件Abaqus 6.14中,对各组模型设置约束及载荷条件,建立分析作业,得出应力分布及变化,采用方差分析、SNK-q检验等统计学方法对比分析各组模型中胫距关节面、距腓关节面、跟距关节面、胫腓关节面应力变化情况,以及胫骨内部应力变化情况。结果A组踝关节受力时各关节面应力由大到小依次为跟距关节面、胫距关节面、距腓关节面、胫腓关节面,B、C、D、E 4个观察组各关节面应力由大到小分别为胫距关节面、跟距关节面、距腓关节面、胫腓关节面;截骨后胫腓关节面、距腓关节面应力明显减小,胫骨内侧受力大大增加,胫距关节面应力向内移位。5组模型间比较,以及4个观察组踝关节模型各关节面应力分别与对照组比较,差异均有统计学意义(P值均<0.001)。与A组比较,4个观察组中胫距关节面应力和跟距关节面应力均增大(其中以B组的应力最大),距腓关节面应力和胫腓关节面应力均减小(其中以B组的应力最小),而且截骨位置越低应力改变越显著,差异均有统计学意义(P值均<0.001)。观察组各组间两两比较,除了C组与D组的跟距关节面比较差异均无统计学意义(P值均>0.05)外,其他各组间比较差异均有统计学意义(P值均<0.05)。结论随着腓骨截骨位置的降低,踝关节各关节面应力变化均增大。因此,临床上行腓骨移植修复下颌骨缺损等手术时,在保障修复效果的前提下,应该尽可能多地保留远端腓骨,以最大限度地减少腓骨截骨术后对踝关节功能的影响。

Objective To investigate the mechanical changes of different heights of perfibular osteotomy and their influence on ankle joint and provide theoretical guidance for the selection of appropriate location of perfibular osteotomy for the repair of mandible defect.Methods The left-lower-limb computed tomography(CT)imaging data of 10 patients from the CT room of the First Affiliated Hospital of Bengbu Medical College from June 2020 to June 2022 were included(7 males and 3 females aged 20-60 years old,with a median age of 43 years old).Four patients had oral cancer,and six had right lower limb fracture.Based on the original CT scan data of patients,three-dimensional finite element models containing the tibia,fibula,and ankle joint were constructed using Mimics,Geomagic studio,SolidWorks,Abaqus,and other software.The models were divided into five groups based on the different heights of fibula osteotomy:group A included the bone models containing the complete tibia-fibula and ankle;group B to E comprised the bone models of tibia-fibula and ankle with the 8 cm long fibula intercepted upward at 5,7,9,and 11 cm from the lower end of the fibula.Constraints and loading conditions were set for the models to obtain stress distribution and changes.Group A was the control group,and groups B,C,D and E were the observation groups.In the finite element analysis software Abaqus 6.14,constraints and loading conditions were set for each group of models,and an analysis operation was established to obtain the stress distribution and changes.Statistical methods,such as variance analysis and Student-Newman-Keuls-q test,were used to compare the stress changes of the tibial talus articular,talus articular,calcantalus articular,and tibial articular surfaces in each group of models and changes in internal stress in tibia.Results The joint surface stress of group A was as follows in descending order:talocalcaneal joint surface,tibiotalar articular surface,talofibular articular surface,tibiofibular articular surface.The joint surface stress of groups B,C,D,and E was as follows in descending order:tibiofibular articular surface,talocalcaneal joint surface,talofibular articular surface,tibiofibular articular surface.The stress on tibiofibular articular and talofibular articular surfaces decreased significantly due to structural changes after osteotomy,the stress on medial tibia increased significantly,and that on the tibiotalobular articular surface shifted inward.Statistically significant differences were observed in the joint surface stress of the ankle joint model in five model groups and four observation groups compared with the control group(all P values<0.001).Compared with group A,the stress on the tibial talus articular and calcantalus articular surfaces in the four observation groups increased(group B had the highest stress),whereas the stress on the talofibular articular surface and the tibiofibulan joint surface decreased(group B had the lowest stress).The lower the osteotomy position,the more significant the stress change,with statistical significance(all P values<0.001).In the observation group,pairwise comparison among groups showed no statistical significance except the talocalcaneal joint surface between group C and group D(all P values>0.05),and the other groups had statistical significance(all P values<0.05).Conclusion The lower the position of peroneal osteotomy,the greater the stress change of the ankle joint surface.Therefore,in clinical operations,such as upward fibula transplantation,for the repair of mandibular defects,keeping more distal fibula as much as possible can minimize the influence of fibula osteotomy on ankle joint function under the premise of guaranteeing repair effect.