Fracture prediction for the proximal femur using finite element models: Part II--Nonlinear analysis.
Fracture prediction for the proximal femur using finite element models: Part II--Nonlinear analysis.
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使用有限元模型预测股骨近端骨折：第二部分——非线性分析。
DOI：
10.1115/1.2895413
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Hayes,WC
中科院分区：
文献类型：
--
作者：
Lotz,JC;Cheal,EJ;Hayes,WC
在第一部分中，我们报告了利用定量计算机断层扫描收集的几何和本构数据建立股骨近端线性有限元模型的结果。当用于预测最终破坏载荷时，这些模型与体外研究显示出很好的一致性。在第二部分中，我们报告了我们对这些有限元模型的扩展，以包括骨小梁和皮质骨的非线性行为。用于表示混凝土的高度非线性材料定律用于小梁骨，而双线性材料定律用于皮质骨。我们发现，模型预测和体外骨折数据之间对于骨屈服和骨折的起始时间都有很好的一致性。对于骨骼屈服，模型预测模拟单腿站立的负荷在2%以内，模拟跌倒的负荷在1%以内。对于骨折，模型的预测分别在1%和17%以内。模型还显示了两种不同加载方式下的不同断裂机制。对于单腿站立，首先发生在首都下区域的初级压缩小梁内的破坏，导致负荷转移，并最终导致周围皮质壳的破坏。然而，对于一次跌倒，皮质和松质骨的失效同时发生在粗隆间区域。这些结果支持我们之前的发现，即资本下区的强度主要来自小梁骨，而粗隆间区域的强度主要来自皮质骨。
In Part I we reported the results of linear finite element models of the proximal femur generated using geometric and constitutive data collected with quantitative computed tomography. These models demonstrated excellent agreement with in vitro studies when used to predict ultimate failure loads. In Part II, we report our extension of those finite element models to include nonlinear behavior of the trabecular and cortical bone. A highly nonlinear material law, originally designed for representing concrete, was used for trabecular bone, while a bilinear material law was used for cortical bone. We found excellent agreement between the model predictions and in vitro fracture data for both the onset of bone yielding and bone fracture. For bone yielding, the model predictions were within 2 percent for a load which simulated one-legged stance and 1 percent for a load which simulated a fall. For bone fracture, the model predictions were within 1 percent and 17 percent, respectively. The models also demonstrated different fracture mechanisms for the two different loading configurations. For one-legged stance, failure within the primary compressive trabeculae at the subcapital region occurred first, leading to load transfer and, ultimately, failure of the surrounding cortical shell. However, for a fall, failure of the cortical and trabecular bone occurred simultaneously within the intertrochanteric region. These results support our previous findings that the strength of the subcapital region is primarily due to trabecular bone whereas the strength of the intertrochanteric region is primarily due to cortical bone.