Loundagin Lindsay L, Haider Ifaz T, Cooper David M L, Edwards W Brent
Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada.
McCaig Institute for Bone and Joint Health, University of Calgary, 3280 Hospital Dr NW, Calgary, AB T2N 4Z6, Canada.
Bone Rep. 2020 Mar 5;12:100254. doi: 10.1016/j.bonr.2020.100254. eCollection 2020 Jun.
Many mechanical properties of cortical bone are largely governed by the underlying microarchitecture; however, the influence of microarchitecture on the fatigue life of bone is poorly understood. Furthermore, imaging-based studies investigating intracortical microarchitecture may expose bone samples to large doses of radiation that may compromise fatigue resistance. The purpose of this pilot study was to 1) investigate the relationship between intracortical microarchitecture and the fatigue life of human bone in compression and 2) examine the effects of synchrotron irradiation on fatigue life measurements. Cortical samples were prepared from the femoral and tibial shafts of three cadaveric donors. A subset of samples was imaged using synchrotron X-ray microCT to quantify microarchitecture, including porosity, canal diameter, lacunar density, lacunar volume, and lacunar orientation. A second group of control samples was not imaged and used only for mechanical testing. Fatigue life was quantified by cyclically loading both groups in zero-compression until failure. Increased porosity and larger canal diameter were both logarithmically related to a shorter fatigue life, whereas lacunar density demonstrated a positive linear relationship with fatigue life (r = 45-73%, depending on measure). Irradiation from microCT scanning reduced fatigue life measurements by 91%, but relationships with microarchitecture measurements remained. Additional research is needed to support the findings of this pilot study and fully establish the relationship between intracortical microarchitecture and the compressive fatigue life of bone.
皮质骨的许多力学性能在很大程度上受其潜在微观结构的支配；然而，微观结构对骨疲劳寿命的影响却鲜为人知。此外，基于成像的研究在调查皮质内微观结构时，可能会使骨样本暴露于大剂量辐射下，这可能会损害其抗疲劳能力。这项初步研究的目的是：1）研究皮质内微观结构与人体骨压缩疲劳寿命之间的关系；2）检验同步加速器辐射对疲劳寿命测量的影响。从三名尸体供体的股骨干和胫骨干制备皮质样本。使用同步加速器X射线显微CT对一部分样本进行成像，以量化微观结构，包括孔隙率、管腔直径、骨陷窝密度、骨陷窝体积和骨陷窝方向。第二组对照样本未进行成像，仅用于力学测试。通过对两组样本进行零压缩循环加载直至失效来量化疲劳寿命。孔隙率增加和管腔直径增大均与较短的疲劳寿命呈对数关系，而骨陷窝密度与疲劳寿命呈正线性关系（r = 45 - 73%，取决于测量指标）。显微CT扫描产生的辐射使疲劳寿命测量值降低了91%，但与微观结构测量值的关系依然存在。需要进一步的研究来支持这项初步研究的结果，并全面确立皮质内微观结构与骨压缩疲劳寿命之间的关系。
