Subject-specific finite element models implementing a maximum principal strain criterion are able to estimate failure risk and fracture location on human femurs tested in vitro
Subject-specific finite element models implementing a maximum principal strain criterion are able to estimate failure risk and fracture location on human femurs tested in vitro
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DOI：
10.1016/j.jbiomech.2007.09.009
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发表时间：
2008-01-01
影响因子：
2.4
通讯作者：
Viceconti, Marco
中科院分区：
文献类型：
--
作者：
Schileo, Enrico;Taddei, Fulvia;Viceconti, Marco
在以预测骨骼骨折风险为目的的有限元研究中，文献中对骨组织的破坏准则的选择没有达成一致。基于应力的标准似乎比基于应变的标准更受欢迎，而基本的骨生物力学建议使用应变参数来描述失败。目前结合实验-数值研究的目的是验证，使用特定主题的有限元模型能够准确预测应变，如果基于应变的破坏准则可以识别骨骼的破坏模式。三具尸体股骨被ct扫描，随后在临床相关的单站加载场景中骨折。获取载荷-位移曲线和高速影像，分别确定破坏载荷和断裂起始位置。根据经过验证的程序，根据CT数据建立了三个股骨的特定对象有限元模型。在有限元模型中采用了最大主应变准则，并选择了两种基于应力的准则进行比较。将测量到的破坏载荷应用于模型，并将计算的断裂风险与实验测试结果进行比较。所提出的主应变准则能够正确识别所有模型试样的破坏风险水平和断裂发生位置，而Von Mises或最大主应力准则没有提供重要信息。因此，最大主应变标准可以定义为长骨体内危险因素评估的合适候选者。(c) 2007 Elsevier Ltd.版权所有。
No agreement on the choice of the failure criterion to adopt for the bone tissue can be found in the literature among the finite element studies aiming at predicting fracture risk of bones. The use of stress-based criteria seems to prevail on strain-based ones, while basic bone biomechanics suggest using strain parameters to describe failure. The aim of the present combined experimental-numerical study was to verify, usinig subject-specific finite element models able to accurately predict strains, if a strain-based failure criterion could identify the failure patterns of bones.Three cadaver femurs were CT-scanned and subsequently fractured in a clinically relevant single-stance loading scenario. Load-displacement curves and high-speed movies were acquired to define the failure load and the location of fracture onset, respectively. Subject-specific finite element models of the three femurs were built from CT data following a validated procedure. A maximum principal strain criterion was implemented in the finite element models, and two stress-based criteria selected for comparison. The failure loads measured were applied to the models, and the computed risks of fracture were compared to the results of the experimental tests.The proposed principal strain criterion managed to correctly identify the level of failure risk and the location of fracture onset in all the modelled specimens, while Von Mises or maximum principal stress criteria did not give significant information. A maximum principal strain criterion can thus be defined a suitable candidate for the in vivo risk factor assessment on long bones. (c) 2007 Elsevier Ltd. All rights reserved.