Berlin-Brandenburg Center for Regenerative Therapies, Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
Laboratoire d'Imagerie Biomédicale, Sorbonne Universités, INSERM UMR S 1146, CNRS UMR, 7371, Paris, France; Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK.
Med Eng Phys. 2020 May;79:60-66. doi: 10.1016/j.medengphy.2020.03.005. Epub 2020 Apr 12.
In the human femoral neck, the contribution of the cortical and trabecular architecture to mechanical strength is known to depend on the load direction. In this work, we investigate if QCT-derived homogenized voxel finite element (hvFE) simulations of varying hip loading conditions can be used to study the architecture of the femoral neck. The strength of 19 pairs of human femora was measured ex vivo using nonlinear hvFE models derived from high-resolution peripheral QCT scans (voxel size: 30.3 µm). Standing and side-backwards falling loads were modeled. Quasi-static mechanical tests were performed on 20 bones for comparison. Associations of femur strength with volumetric bone mineral density (vBMD) or microstructural parameters of the femoral neck obtained from high-resolution QCT were compared between mechanical tests and simulations and between standing and falling loads. Proximal femur strength predictions by hvFE models were positively associated with the vBMD of the femoral neck (R² > 0.61, p < 0.001), as well as with its cortical thickness (R² > 0.27, p < 0.001), trabecular bone volume fraction (R² = 0.42, p < 0.001) and with the first two principal components of the femoral neck architecture (R² > 0.38, p < 0.001). Associations between femur strength and femoral neck microarchitecture were stronger for one-legged standing than for side-backwards falling. For both loading directions, associations between structural parameters and femur strength from hvFE models were in good agreement with those from mechanical tests. This suggests that hvFE models can reflect the load-direction-specific contribution of the femoral neck microarchitecture to femur strength.
在人体股骨颈中，皮质和小梁结构对机械强度的贡献已知取决于载荷方向。在这项工作中，我们研究了 QCT 衍生的均匀化体素有限元（hvFE）模拟不同髋部加载条件是否可用于研究股骨颈的结构。使用源自高分辨率外周 QCT 扫描的非线性 hvFE 模型（体素大小：30.3µm），对 19 对人体股骨进行了离体强度测量。模拟了站立和向后侧摔倒两种加载情况。对 20 根骨头进行了准静态机械测试作为比较。比较了机械测试和模拟之间以及站立和摔倒加载之间股骨强度与高分辨率 QCT 获得的体积骨矿物质密度（vBMD）或股骨颈微观结构参数的相关性。hvFE 模型对股骨近端强度的预测与股骨颈的 vBMD（R²＞0.61，p＜0.001）以及皮质厚度（R²＞0.27，p＜0.001）、小梁骨体积分数（R²＝0.42，p＜0.001）和股骨颈结构的前两个主成分（R²＞0.38，p＜0.001）呈正相关。在单腿站立时，股骨强度与股骨颈微观结构之间的相关性强于向后摔倒。对于两种加载方向，hvFE 模型中结构参数与股骨强度之间的相关性与机械测试的相关性吻合良好。这表明 hvFE 模型可以反映股骨颈微观结构对股骨强度的特定载荷方向的贡献。
