High-speed photography of compressed human trabecular bone correlates whitening to microscopic damage
High-speed photography of compressed human trabecular bone correlates whitening to microscopic damage
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DOI：
10.1016/j.engfracmech.2006.05.024
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发表时间：
2007-08-01
影响因子：
5.4
通讯作者：
Hansma, P. K.
中科院分区：
文献类型：
--
作者：
Thurner, P. J.;Erickson, B.;Hansma, P. K.
骨小梁的力学测试主要是由于绝经后妇女和社会老年人骨质疏松症对社会和医疗保健成本的巨大影响。骨小梁丢失和力学性能受损降低了骨强度，增加了骨折风险，尤其是在椎骨。人们普遍认为，除了骨密度外，骨的微结构和材料特性也对骨强度和骨折风险起着重要作用。为了克服标准力学测试仅提供复杂样本的完整信息的局限性，设计了分步力学测试的实验，同时对骨小梁和皮质骨进行成像。在这种交流中，我们提出了一种利用高速摄影对压缩过程中的骨小梁进行实时成像的方法，并研究了变形的骨小梁变白是否是由于微损伤所致的假说。对来自健康男性捐赠者的人类松质骨样本进行的实验表明，此类样本的破坏高度局限于骨折带。此外，可以看到强烈变形的小梁变白，这一效果类似于聚合物中的应力增白。同一感兴趣区的扫描电子显微镜显示，变白的小梁受到微裂纹的强烈破坏，大部分分层失败。更高分辨率的图像显示了横跨裂缝的矿化胶原纤维。卸载样品后，白化部分褪色，可能是由于部分裂纹闭合。总体而言，高速摄影能够在机械测试期间实时检测微损伤，并提供与记录的应力应变曲线的关联。(C)2006爱思唯尔有限公司。保留所有权利。
Mechanical testing of trabecular bone is mainly motivated by the huge impact of osteoporosis in post-menopausal women and the aged in society in terms of social and health care costs. Trabecular bone loss and impairment of its mechanical properties reduce bone strength and increase fracture risk, especially in vertebrae. It is generally accepted that in addition to bone mineral density, microarchitecture and material properties of bone also play important roles for bone strength and fracture risk. In order to overcome the limitations of standard mechanical tests delivering merely integral information about complicated samples, experiments were designed for step-wise mechanical testing with concurrent imaging of trabecular and cortical bone. In this communication we present an approach for real-time imaging of trabecular bone during compression using high-speed photography and investigate the hypothesis whether the whitening of deformed trabeculae is due to microdamage. Experiments on human trabecular bone samples from a healthy male donor revealed that failure of such samples is highly localized in fracture bands. Moreover, strongly deformed trabeculae were seen to whiten, an effect similar to stress whitening in polymers. Scanning Electron Microscopy of the same regions of interest revealed that whitened trabeculae were strongly damaged by microscopic cracks and mostly failed in delamination. Higher resolution images uncovered mineralized collagen fibrils spanning the cracks. The whitening partially faded after unloading of the samples, presumably due to partial crack closure. Overall, high-speed photography enables microdamage detection in real-time during a mechanical test and provides a correlation to recorded stress strain curves. (C) 2006 Elsevier Ltd. All rights reserved.