手法复位先天性马蹄内翻足过程中的力学变化

The preliminary study of mechanical changes in the course of manipulative reduction of congenital clubfoot

目的从力学角度探讨先天性马蹄内翻足(CCF)手法复位过程中跟腱对跟骨于距下关节的位移变化的影响及跟腱对距舟关节周围韧带的作用。方法对1例CCF住院患儿双足进行螺旋CT扫描,应用CT扫描技术、图形数字化方法获取患足踝的三维坐标,利用ANSYS10.0有限元分析软件等工具建立足踝的三维有限元模型,观察并分析有无跟腱作用情况下距舟关节复位过程中跟骨的位移变化及距舟关节周围韧带的受力变化,并进行统计学分析。结果①距舟关节逐渐复位的过程中,跟骨在距下确有一个外展运动,向外的位移随舟骨处施加拉力的增加而呈线性增加。②当无跟腱拉力时,跟骨的位移要比有跟腱拉力时的位移大,但差异无统计学意义(P>0.05)。③跟腱拉力释放使距舟关节内侧韧带受力和增加。结论应用三维有限元法分析方法证实了并量化在手法治疗CCF过程中跟骨的位移,从生物力学角度说明跟腱松解有利于跟骨的复位,为CCF的研究提供一种新的思路。

Objective To set up the three-dimensional（3D）finite element model of foot of congenital clubfoot（CCF）on the basis of CT medical images,and analyze the biomechanical characteristics.Methods One patient with bilateral CCF was selected,whose feet hadn＇t injured history.CT scan and graphics digital technique were used to obtain 3D coordinates of the foot and ankle joint,and the 3D finite element model was developed by using ANSYS10.0 finite element software and other toots.The displacement of the calcaneous and stress distribution in talonavicular joint ligaments were recorded.Results The research simulating the process of navicular reduction,the displacement of the calcaneous was no significant difference whether or not there is tension from Achilles tendon（P0.05）.The medial ligament had great impact on calcaneal displacement.In the three-dimensional model during the talonavicular joint reduction,the force of the Achilles tendon there is no significant on displacement of the calcaneal.While during the talonavicular joint reduction the medial tendon receive more force if the force of Achilles tendon reduced to 0.Conclusions Using 3D finite element models to analyze the mechanical trait during the manipulative reduction of clubfoot are feasible,and gain some unique information,which provides a new path to study CCF.