Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, USA.
Department of Bioengineering, Northeastern University, Boston, MA, USA.
Curr Osteoporos Rep. 2018 Aug;16(4):404-410. doi: 10.1007/s11914-018-0449-5.
Osteoporosis could lead to the bone mechanical failure. To examine the bone health, mechanical properties are often estimated from the images of the bone density. Here, we review the relationships that have been experimentally determined between mineral density and the elastic modulus and factors that affect these relationships.
Studies, which have investigated the relation between the elastic modulus and bone mineral at the bulk scale, have shown that approximately 70% of variations in the elastic modulus can be explained based on the amount of mineral in bone. At the tissue level, however, higher resolution techniques are used to characterize the density and modulus more locally, and this leads to the correlation of mineral with modulus to be not as strong as that of the bulk level and often times, insignificant. This observation indicates the importance of structural hierarchy and mineral crystal organization in determining the local stiffness of the bone tissue. At the bulk level in bone (cm scale), modulus (E) is related to density (ρ) through a power law relationship (E ∝ ρ). At the tissue level (μm-mm scale), the relationship between the modulus and density is weak, likely due to the effect of microstructural features at small length scales.
骨质疏松症可导致骨骼力学失效。为了评估骨骼健康，力学性能通常通过骨密度图像来估计。在这里，我们回顾了已经在实验上确定的矿物质密度与弹性模量之间的关系，以及影响这些关系的因素。
研究表明，在整体尺度上，弹性模量与骨矿物质之间的关系，大约 70%的弹性模量变化可以根据骨矿物质的含量来解释。然而，在组织水平上，更高分辨率的技术被用来更局部地描述密度和模量，这导致矿物质与模量的相关性不如整体水平强，而且通常情况下，相关性不显著。这一观察结果表明了结构层次和矿物质晶体组织在决定骨组织局部刚度方面的重要性。在骨骼的整体水平（厘米尺度），模量（E）与密度（ρ）通过幂律关系（E∝ρ）相关。在组织水平（μm-mm 尺度），模量和密度之间的关系较弱，这可能是由于在小尺度上微结构特征的影响。
