Morgan E F, Keaveny T M
Orthopaedic Biomechanics Laboratory, Department of Mechanical Engineering, University of California, 2166 Etcheverry Hall, Berkeley, CA 94720-1740, USA.
J Biomech. 2001 May;34(5):569-77. doi: 10.1016/s0021-9290(01)00011-2.
Understanding the dependence of human trabecular bone strength behavior on anatomic site provides insight into structure-function relationships and is essential to the increased success of site-specific finite element models of whole bones. To investigate the hypothesis that the yield strains of human trabecular bone depend on anatomic site, the uniaxial tensile and compressive yield properties were compared for cylindrical specimens from the vertebra (n=61), proximal tibia (n=31), femoral greater trochanter (n=23), and femoral neck (n=27) taken from 61 donors (67+/-15years). Test protocols were used that minimized end artifacts and loaded specimens along the main trabecular orientation. Yield strains by site (mean+/-S.D.) ranged from 0.70+/-0.05% for the trochanter to 0.85+/-0.10% for the femoral neck in compression, from 0.61+/-0.05% for the trochanter to 0.70+/-0.05% for the vertebra in tension, and were always higher in compression than tension (p<0.001). The compressive yield strain was higher for the femoral neck than for all other sites (p<0.001), as was the tensile yield strain for the vertebra (p<0.007). Analysis of covariance, with apparent density as the covariate, indicated that inter-site differences existed in yield stress even after adjusting statistically for density (p<0.035). Coefficients of variation in yield strain within each site ranged from only 5-12%, consistent with the strong linear correlations (r(2)=0.94-0.98) found between yield stress and modulus. These results establish that the yield strains of human trabecular bone can differ across sites, but that yield strain may be considered uniform within a given site despite substantial variation in elastic modulus and yield stress.
了解人类小梁骨强度行为对解剖部位的依赖性，有助于洞察结构-功能关系，对于提高全骨特定部位有限元模型的成功率至关重要。为了研究人类小梁骨屈服应变取决于解剖部位这一假设，对来自61名捐赠者（67±15岁）的椎骨（n = 61）、胫骨近端（n = 31）、股骨大转子（n = 23）和股骨颈（n = 27）的圆柱形标本的单轴拉伸和压缩屈服特性进行了比较。采用的测试方案将端部伪影降至最低，并沿主要小梁方向加载标本。各部位的屈服应变（平均值±标准差）在压缩时从大转子的0.70±0.05%到股骨颈的0.85±0.10%，在拉伸时从大转子的0.61±0.05%到椎骨的0.70±0.05%，且压缩时的屈服应变总是高于拉伸时的屈服应变（p<0.001）。股骨颈的压缩屈服应变高于所有其他部位（p<0.001），椎骨的拉伸屈服应变也高于其他部位（p<0.007）。以表观密度为协变量的协方差分析表明，即使在对密度进行统计调整后，各部位之间的屈服应力仍存在差异（p<0.035）。每个部位屈服应变的变异系数仅在5-12%之间，这与屈服应力和模量之间的强线性相关性（r² = 0.94-0.98）一致。这些结果表明，人类小梁骨的屈服应变在不同部位可能不同，但尽管弹性模量和屈服应力存在很大差异，在给定部位内屈服应变可被视为均匀的。
