Department of Mechanical Engineering, Notre Dame University-Louaize, Zouk Mikael, P.O. Box: 72, Zouk Mosbeh, Lebanon.
Department of Mathematics, Notre Dame University-Louaize, Zouk Mikael, P.O. Box: 72, Zouk Mosbeh, Lebanon.
J Bone Miner Metab. 2021 Sep;39(5):725-736. doi: 10.1007/s00774-021-01217-2. Epub 2021 Apr 6.
While bone literature abounds with correlations of mechanical stiffness to mineralization, such correlations are reported without relating the findings to specific intracortical locations. This study reports on mapping of stiffness and mineralization distributions in ring-shaped cortical bone samples sliced from mid-diaphyseal bovine femur. Stiffness and mineralization measurements were conducted at points across the intracortical thickness along radial lines emanating from the inner (endosteal) surface to the outer (periosteal) surface. Measurements were taken along approximately 4 mm distance of cortical bone thickness.
Three experimental techniques were employed: Vickers microhardness (HV), energy-dispersive X-ray (EDX) spectroscopy, and computed tomography (CT). Stiffness values were extracted from the Vickers microhardness tests. Elemental mineralization values (calcium %wt. and phosphorus %wt.) were determined from EDX data. All measurements were repeated on three different femur bones taken from different bovines (collected fresh from butcher).
The study plots stiffness values and elemental mineralization (calcium %wt. and phosphorus %wt.) versus cortical thickness. Both stiffness and Ca %wt. and P %wt. are found to track and to linearly increase when plotted along the radial distance. The stiffness and mineralization trends collected from Vickers and EDX measurements were verified by employing the CT number (Hounsfield units, HU) via CT scans of the same bone samples. Data fitting via statistical methods revealed that all correlations were statistically significant.
Starting from endosteal to periosteal surfaces of mid-diaphyseal bovine femur, it was found that stiffness, mineralization, and HU values all exhibit increasing and correlating trends.
尽管骨骼文献中充斥着力学刚度与矿化程度的相关性，但这些相关性的报告并未将研究结果与特定的皮质内位置相关联。本研究报告了从中段骨髓腔牛股骨切取的环形皮质骨样本中刚度和矿化分布的测绘。在从内（骨内膜）表面到外（骨外膜）表面的放射状线穿过皮质内厚度的各个点进行刚度和矿化测量。测量是在大约 4 毫米厚的皮质骨厚度上进行的。
采用了三种实验技术：维氏显微硬度（HV）、能谱 X 射线（EDX）光谱和计算机断层扫描（CT）。从维氏显微硬度测试中提取刚度值。从 EDX 数据确定元素矿化值（钙%wt.和磷%wt.）。所有测量均在来自不同牛的三个不同股骨上重复进行（从屠夫处收集新鲜样本）。
本研究绘制了刚度值和元素矿化（钙%wt.和磷%wt.）与皮质厚度的关系图。发现刚度和 Ca %wt.和 P %wt.均沿径向距离追踪并呈线性增加。通过对同一骨样本进行 CT 扫描，使用 CT 号（亨氏单位，HU）验证了维氏和 EDX 测量得到的刚度和矿化趋势。通过统计方法进行的数据拟合表明，所有相关性均具有统计学意义。
从中段骨髓腔牛股骨的骨内膜到骨外膜表面开始，发现刚度、矿化和 HU 值均表现出增加和相关的趋势。
