Department of Radiology, University of Calgary, Calgary, Alberta, Canada.
Department of Mechanical and Materials Engineering, The University of Western Ontario, London, Ontario, Canada.
J Orthop Res. 2022 Sep;40(9):2039-2047. doi: 10.1002/jor.25229. Epub 2021 Dec 2.
Subchondral trabecular bone (STB) undergoes adaptive changes during osteoarthritic (OA) disease progression. These changes alter both the mineralization patterns and structure of bone and may contribute to variations in the mechanical properties. Similarly, when images are downsampled - as is often performed in micro finite element model (microFEM) generation - the morphological and mineralization patterns may further alter the mechanical properties due to partial volume effects. MicroFEMs accounting for material heterogeneity can account for these tissue variations, but no studies have validated these with robust full-field testing methods. As such, this study compared homogeneous and heterogeneous microFEMs to experimentally loaded trabecular bone cores from the humeral head combined with digital volume correlation (DVC). These microFEMs were used to compare apparent mechanical properties between normal and OA STB. Morphological and mineralization patterns between groups were also compared. There were no significant differences in tissue or bone mineral density between groups. The only significant differences in morphometric parameters were in trabecular thickness between groups. There were no significant differences in linear regression parameters between normal and OA STB apparent mechanical properties estimated using heterogeneous microFEMs with an element-wise bilinear elastic-plastic constitutive model. Clinical significance: Validated heterogeneous microFEMs applied to STB of the humeral head have the potential to significantly improve our understanding of mechanical variations in the bone that occur during OA progression.
软骨下骨小梁（STB）在骨关节炎（OA）疾病进展过程中会发生适应性变化。这些变化改变了骨的矿化模式和结构，可能导致力学性能的变化。同样，当图像进行下采样时 - 正如在微有限元模型（microFEM）生成中经常执行的那样 - 由于部分体积效应，形态和矿化模式可能进一步改变力学性能。考虑到材料异质性的 microFEM 可以解释这些组织变化，但没有研究使用强大的全场测试方法对其进行验证。因此，本研究将均质和非均质 microFEM 与来自肱骨头的实验加载骨小梁核心进行了比较，同时结合了数字体相关（DVC）技术。这些 microFEM 用于比较正常和 OA STB 的表观力学性能。还比较了组间的形态和矿化模式。组间的组织或骨矿物质密度没有显著差异。在组间形态参数中，只有骨小梁厚度存在显著差异。使用具有元素双线性弹塑性本构模型的非均质 microFEM 估计正常和 OA STB 的表观力学性能的线性回归参数没有显著差异。临床意义：应用于肱骨头 STB 的经过验证的非均质 microFEM 有潜力显著提高我们对 OA 进展过程中骨力学变化的理解。
