Tuncer Mahmut, Hansen Ulrich N, Amis Andrew A
Department of Mechanical Engineering, Imperial College London, Exhibition Road, London SW7 2AZ, UK.
Department of Mechanical Engineering, Imperial College London, Exhibition Road, London SW7 2AZ, UK; Musculoskeletal Surgery Laboratory, Imperial College London School of Medicine, Charing Cross Hospital, London W6 8RF, UK.
Med Eng Phys. 2014 Aug;36(8):991-7; discussion 991. doi: 10.1016/j.medengphy.2014.04.006. Epub 2014 Jun 3.
Although finite element (FE) models can provide distinct benefits in understanding knee biomechanics, in particular the response of the knee to implants, their usefulness is limited by the modelling assumptions and input parameters. This study highlights the uncertainty of material input parameters derived from the literature and its limitation on the accuracy and usefulness of FE models of the tibia. An FE model of the intact human knee and a database of knee forces (muscles, ligaments and medial and lateral tibio-femoral contacts) were developed for walking and stair-descent activities. Ten models were constructed from ten different combinations of apparent bone density to elastic modulus material property relationships, published in the literature. Some of the published material property relationships led to predictions of bone strains in the proximal tibia which exceeded published failure criteria under loads imposed by normal activities. These relationships appear not to be applicable for the human tibia. There is a large discrepancy in proposed relationships that cover the cancellous bone density range. For FE models of the human tibia, the material relationship proposed by Morgan et al., which assumed species and anatomic site dependence, produced the most believable results for cancellous bone. In addition to casting doubt on the use of some of the published density-modulus relationships for analysis of the human proximal tibia, this study highlights the need for further experimental work to characterise the behaviour of bone with intermediate densities.
尽管有限元（FE）模型在理解膝关节生物力学，特别是膝关节对植入物的反应方面能带来显著益处，但其有效性受到建模假设和输入参数的限制。本研究强调了从文献中获取的材料输入参数的不确定性及其对胫骨有限元模型准确性和有效性的限制。针对步行和下楼梯活动，建立了完整人体膝关节的有限元模型以及膝关节力（肌肉、韧带和内侧及外侧胫股接触力）数据库。根据文献中公布的表观骨密度与弹性模量材料属性关系的十种不同组合构建了十个模型。一些已发表的材料属性关系导致对胫骨近端骨应变的预测在正常活动施加的负荷下超过了已公布的失效标准。这些关系似乎不适用于人类胫骨。在所涵盖的松质骨密度范围内，已提出的关系存在很大差异。对于人类胫骨的有限元模型，Morgan等人提出的假设物种和解剖部位依赖性的材料关系，对于松质骨产生了最可信的结果。除了对一些已发表的密度 - 模量关系用于分析人类胫骨近端的适用性提出质疑外，本研究还强调需要进一步开展实验工作来表征中等密度骨的行为。
