Johnson Joshua E, Troy Karen L
Worcester Polytechnic Institute, Department of Biomedical Engineering, 100 Institute Road, Worcester, MA 01609, United States.
J Biomech. 2018 Jan 3;66:180-185. doi: 10.1016/j.jbiomech.2017.10.036. Epub 2017 Nov 4.
High-resolution peripheral quantitative computed tomography (HR-pQCT) derived micro-finite element (FE) modeling is used to evaluate mechanical behavior at the distal radius microstructure. However, these analyses typically simulate non-physiologic simplified platen-compression boundary conditions on a small section of the distal radius. Cortical and trabecular regions contribute uniquely to distal radius mechanical behavior, and various factors affect these regions distinctly. Generalized strength predictions from standardized platen-compression analyses may not adequately capture region specific responses in bone. Our goal was to compare load sharing within the cortical-trabecular compartments between the standardized platen-compression BC simulations, and physiologic BC simulations using a validated multiscale approach. Clinical- and high-resolution images were acquired from nine cadaveric forearm specimens using an HR-pQCT scanner. Multiscale FE models simulating physiologic BCs, and micro-FE only models simulating platen-compression BCs were created for each specimen. Cortical and trabecular loads (N) along the length of the distal radius micro-FE section were compared between BCs using correlations. Principal strain distributions were also compared quantitatively. Cortical and trabecular loads from the platen-compression BC simulations were strongly correlated to the physiologic BC simulations. However, a 30% difference in cortical loads distally, and a 53% difference in trabecular loads proximally was observed under platen BC simulations. Also, distribution of principal strains was clearly different. Our data indicated that platen-compression BC simulations alter cortical-trabecular load sharing. Therefore, results from these analyses should be interpreted in the appropriate mechanical context for clinical evaluations of normal and pathologic mechanical behavior at the distal radius.
高分辨率外周定量计算机断层扫描（HR-pQCT）衍生的微观有限元（FE）建模用于评估桡骨远端微观结构的力学行为。然而，这些分析通常在桡骨远端的一小部分上模拟非生理性的简化压板压缩边界条件。皮质和小梁区域对桡骨远端力学行为有独特贡献，并且各种因素对这些区域的影响明显不同。来自标准化压板压缩分析的广义强度预测可能无法充分捕捉骨骼中特定区域的反应。我们的目标是使用经过验证的多尺度方法，比较标准化压板压缩边界条件模拟与生理边界条件模拟之间皮质-小梁隔室内的负荷分担情况。使用HR-pQCT扫描仪从九个尸体前臂标本获取临床和高分辨率图像。为每个标本创建了模拟生理边界条件的多尺度有限元模型和仅模拟压板压缩边界条件的微观有限元模型。使用相关性比较了两种边界条件下沿桡骨远端微观有限元部分长度的皮质和小梁负荷（N）。还定量比较了主应变分布。压板压缩边界条件模拟的皮质和小梁负荷与生理边界条件模拟密切相关。然而，在压板边界条件模拟下，观察到远端皮质负荷有30%的差异，近端小梁负荷有53%的差异。此外，主应变分布明显不同。我们的数据表明，压板压缩边界条件模拟会改变皮质-小梁负荷分担。因此，在对桡骨远端正常和病理力学行为进行临床评估时，应在适当的力学背景下解释这些分析结果。
