Guiotto Annamaria, Sawacha Zimi, Guarneri Gabriella, Avogaro Angelo, Cobelli Claudio
Department of Information Engineering, University of Padova, Via Gradenigo 6b I, 35131 Padova, Italy.
Department of Clinical Medicine and Metabolic Disease, University Polyclinic, Via Giustiniani 2, 35128 Padova, Italy.
J Biomech. 2014 Sep 22;47(12):3064-71. doi: 10.1016/j.jbiomech.2014.06.029. Epub 2014 Jul 7.
Diabetic foot is an invalidating complication of diabetes that can lead to foot ulcers. Three-dimensional (3D) finite element analysis (FEA) allows characterizing the loads developed in the different anatomical structures of the foot in dynamic conditions. The aim of this study was to develop a subject specific 3D foot FE model (FEM) of a diabetic neuropathic (DNS) and a healthy (HS) subject, whose subject specificity can be found in term of foot geometry and boundary conditions. Kinematics, kinetics and plantar pressure (PP) data were extracted from the gait analysis trials of the two subjects with this purpose. The FEM were developed segmenting bones, cartilage and skin from MRI and drawing a horizontal plate as ground support. Materials properties were adopted from previous literature. FE simulations were run with the kinematics and kinetics data of four different phases of the stance phase of gait (heel strike, loading response, midstance and push off). FEMs were then driven by group gait data of 10 neuropathic and 10 healthy subjects. Model validation focused on agreement between FEM-simulated and experimental PP. The peak values and the total distribution of the pressures were compared for this purpose. Results showed that the models were less robust when driven from group data and underestimated the PP in each foot subarea. In particular in the case of the neuropathic subject's model the mean errors between experimental and simulated data were around the 20% of the peak values. This knowledge is crucial in understanding the aetiology of diabetic foot.
糖尿病足是糖尿病的一种致残性并发症，可导致足部溃疡。三维（3D）有限元分析（FEA）能够在动态条件下描述足部不同解剖结构中产生的负荷。本研究的目的是建立糖尿病神经病变患者（DNS）和健康受试者（HS）的个体化3D足部有限元模型（FEM），其个体化特性体现在足部几何形状和边界条件方面。为此，从这两名受试者的步态分析试验中提取了运动学、动力学和足底压力（PP）数据。通过从MRI中分割出骨骼、软骨和皮肤并绘制一个水平板作为地面支撑来建立有限元模型。材料属性取自先前的文献。利用步态站立期四个不同阶段（足跟触地、承重反应、支撑中期和蹬离期）的运动学和动力学数据进行有限元模拟。然后，用10名神经病变患者和10名健康受试者的群体步态数据驱动有限元模型。模型验证聚焦于有限元模拟的足底压力与实验足底压力之间的一致性。为此比较了压力的峰值和总分布。结果表明，当由群体数据驱动时，模型的稳健性较差，并且低估了每个足部子区域的足底压力。特别是在神经病变患者的模型中，实验数据与模拟数据之间的平均误差约为峰值的20%。这一知识对于理解糖尿病足的病因至关重要。
