Heterogeneity of yield strain in low-density versus high-density human trabecular bone
Heterogeneity of yield strain in low-density versus high-density human trabecular bone
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DOI：
10.1016/j.jbiomech.2009.05.023
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发表时间：
2009-09-18
影响因子：
2.4
通讯作者：
Keaveny, Tony M.
中科院分区：
文献类型：
--
作者：
Bevill, Grant;Farhamand, Farhad;Keaveny, Tony M.
了解小梁屈服应变的离轴行为可能会对骨折的病因学提供独特的见解，因为屈服应变提供了独立于弹性行为的失效测量。我们试图解决小梁屈服应变的各向异性，同时考虑密度和解剖部位的变化，并确定控制这种行为的机制。圆柱形标本取自椎体（n = 22，BV/TV = 0.11 +/- 0.02）和股骨颈（n = 28，BV/TV = 0.22 +/- 0.06），主要小梁方向要么沿着圆柱轴（轴上，n = 22）对齐，要么以15度或45度的斜角（离轴， n = 28）。每个样本均经过微型 CT 扫描、机械压缩至失效，并采用基于非线性微型 CT 的有限元分析进行分析。屈服应变取决于解剖部位（p = 0.03，方差分析），并且离轴载荷的影响对于两个部位而言是不同的（p = 0.04）——屈服应变随着椎骨离轴载荷的增加而增加（p = 0.04），但对于股骨来说是各向同性的（p = 0.66）。网站汇集在一起。对于轴上载荷，屈服应变与 BV/TV 呈正相关（R-2 = 58%，p < 0.0001），但对于离轴载荷则不存在这种相关性（p = 0.79）。对模量-BV/TV和强度-BV/TV关系的分析表明，对于股骨，与离轴载荷相关的强度降低大于模量，而椎骨则出现相反的趋势。微观有限元分析表明，这些趋势是由于两种类型的骨骼的不同失效机制和不同的加载模式造成的。总而言之，这些结果提供了对人类骨小梁失效行为的独特见解，并强调需要考虑解剖部位和骨体积分数的多轴失效标准。 (C) 2009 Elsevier Ltd. 保留所有权利。
Understanding the off-axis behavior of trabecular yield strains may lend unique insight into the etiology of fractures since yield strains provide measures of failure independent of elastic behavior. We sought to address anisotropy of trabecular yield strains while accounting for variations in both density and anatomic site and to determine the mechanisms governing this behavior. Cylindrical specimens were cored from vertebral bodies (n = 22, BV/TV = 0.11 +/- 0.02) and femoral necks (n = 28, BV/TV = 0.22 +/- 0.06) with the principal trabecular orientation either aligned along the cylinder axis (on-axis, n = 22) or at an oblique angle of 15 degrees or 45 degrees (off-axis, n = 28). Each specimen was scanned with micro-CT, mechanically compressed to failure, and analysed with nonlinear micro-CT-based finite element analysis. Yield strains depended on anatomic site (p = 0.03, ANOVA), and the effect of off-axis loading was different for the two sites (p = 0.04)-yield strains increased for off-axis loading of the vertebral bone (p = 0.04), but were isotropic for the femoral bone (p = 0.66). With sites pooled together. yield strains were positively correlated with BV/TV for on-axis loading (R-2 = 58%, p < 0.0001), but no such correlation existed for off-axis loading (p = 0.79). Analysis of the modulus-BV/TV and strength-BV/TV relationships indicated that, for the femoral bone, the reduction in strength associated with off-axis loading was greater than that for modulus, while the opposite trend occurred for the vertebral bone. The micro-FE analyses indicated that these trends were due to different failure mechanisms for the two types of bone and the different loading modes. Taken together, these results provide unique insight into the failure behavior of human trabecular bone and highlight the need for a multiaxial failure criterion that accounts for anatomic site and bone volume fraction. (C) 2009 Elsevier Ltd. All rights reserved.