To what extent can linear finite element models of human femora predict failure under stance and fall loading configurations?
To what extent can linear finite element models of human femora predict failure under stance and fall loading configurations?
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DOI：
10.1016/j.jbiomech.2014.08.024
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发表时间：
2014-11-07
影响因子：
2.4
通讯作者：
Taddei, Fulvia
中科院分区：
文献类型：
--
作者：
Schileo, Enrico;Balistreri, Luca;Taddei, Fulvia
基于计算机断层扫描(CT)的有限元(FE)模型的股骨近端强度估计正在得到临床应用。已发表的模型达到了很高的体外精度，但其中许多依赖于非线性方法或内部参数的最佳拟合。本研究的目的是验证完全基于独立确定的参数的线性有限元建模程序在多大程度上可以预测股骨近端在站立和侧向跌落载荷状态下的破坏特征。7个股骨在站立加载条件下被测试为失败，7个在跌倒时被测试为失败。用高速录像监测骨折情况。根据已在应变预测中得到验证的程序，从CT图像建立线性有限元模型。非对称最大主应变准则(0.73%拉伸，1.04%压缩极限)被用来定义基于节点的危险因子(RF)。FE-预测的破坏载荷、模式(拉伸/压缩)和位置从第一个节点到Rf=1确定。FE-预测的破坏载荷与测量的破坏载荷高度相关(R2=0.89，SEE=814N)。在所有标本中，有限元模型正确地识别了失效模式(站立时拉伸，跌倒时压缩)和骨折开始的股骨区域(颈上外侧)。总而言之，一个简单的有限元模型，未来适应多种载荷(例如肌肉)，与从正常到骨质疏松的样品在两种载荷条件下的实验失效高度相关。因此，它可用于临床研究。(C)2014爱思唯尔有限公司。保留所有权利。
Proximal femur strength estimates from computed tomography (CT)-based finite element (FE) models are finding clinical application. Published models reached a high in-vitro accuracy, yet many of them rely on nonlinear methodologies or internal best-fitting of parameters. The aim of the present study is to verify to what extent a linear FE modelling procedure, fully based on independently determined parameters, can predict the failure characteristics of the proximal femur in stance and sideways fall loading configurations.Fourteen fresh-frozen cadaver femora were CT-scanned. Seven femora were tested to failure in stance loading conditions, and seven in fall. Fracture was monitored with high-speed videos. Linear FE models were built from CT images according to a procedure already validated in the prediction of strains. An asymmetric maximum principal strain criterion (0.73% tensile, 1.04% compressive limit) was used to define a node-based risk factor (RF). FE-predicted failure load, mode (tensile/compressive) and location were determined from the first node reaching RF=1.FE-predicted and measured failure loads were highly correlated (R-2=0.89, SEE=814 N). In all specimens, FE models correctly identified the failure mode (tensile in stance, compressive in fall) and the femoral region where fracture started (supero-lateral neck aspect). The location of failure onset was accurately predicted in eight specimens.In summary, a simple FE model, adaptable in the future to multiple loads (e.g. including muscles), was highly correlated with experimental failure in two loading conditions on specimens ranging from normal to osteoporotic. Thus, it can be suitable for use in clinical studies. (C) 2014 Elsevier Ltd. All rights reserved.