Departments of Endocrinology & Medicine, Austin Health, University of Melbourne, Melbourne, Australia.
Bone. 2011 Jun 1;48(6):1246-51. doi: 10.1016/j.bone.2011.02.023. Epub 2011 Mar 6.
MINI-ABSTRACT: Study of postmortem samples of cortical bone from the trochanters of 12 Caucasian females revealed that tissue mineral density (TMD) and tissue elastic modulus correlate weakly within and between individuals. Other material properties need to be taken into account to more fully predict variation in tissue elastic modulus.
Bone is a composite material that varies in its material composition and structural organization at the macro-, micro-, and nano-scales. This hierarchical organization is essential for bone's resistance to crack initiation and propagation. We quantified the relationship between regional heterogeneity in TMD and tissue elastic modulus in cortical bone of the trochanter to determine whether TMD can be used as a predictor of tissue elastic modulus.
Measurements of tissue elastic modulus and hardness were made using nanoindentation at 5 × 20 indent points spaced 100 μm apart. TMD at the same location was computed from quantitative backscattered scanning electron microscopy imaging of cortical samples from trochanters obtained at postmortem from 12 Caucasian females (mean age: 69 years; range: 29 to 85 years).
Within an individual, the variance in tissue elastic modulus (CV = 18.7%; range: 9 to 41.5%) was five times greater than the variance in TMD (3.6%, range: 1.8 to 5.7%). On average, only 45% of the variance in tissue elastic modulus was explained by TMD. From individual to individual, the proportion of the variance in tissue elastic modulus explained by TMD ranged from 0 to 64%. In 6 of 12 samples, TMD explained less than 30% of the variance in tissue elastic modulus. Results were similar for tissue hardness.
Tissue mineral density is an incomplete surrogate for tissue elastic modulus. Other material properties need to be accounted for to more fully predict regional variation in tissue elastic modulus.
研究 12 名白种女性大转子皮质骨的死后样本表明，组织矿物质密度（TMD）和组织弹性模量在个体内部和个体之间相关性较弱。需要考虑其他材料特性，以更全面地预测组织弹性模量的变化。
骨骼是一种复合材料，其在宏观、微观和纳米尺度上的材料组成和结构组织存在差异。这种分层组织对于骨骼抵抗裂纹萌生和扩展至关重要。我们量化了大转子皮质骨 TMD 与组织弹性模量的区域性异质性之间的关系，以确定 TMD 是否可以作为组织弹性模量的预测指标。
使用纳米压痕法在相距 100μm 的 5×20 个压痕点处测量组织弹性模量和硬度。在从 12 名白种女性（平均年龄：69 岁；范围：29 至 85 岁）死后获得的大转子皮质样本的定量背散射扫描电子显微镜成像中计算出相同位置的 TMD。
在个体内部，组织弹性模量的变异系数（CV=18.7%；范围：9%至 41.5%）是 TMD 变异系数（3.6%，范围：1.8%至 5.7%）的五倍。平均而言，TMD 仅解释了组织弹性模量变异的 45%。从个体到个体，TMD 解释组织弹性模量变异的比例范围从 0 到 64%。在 12 个样本中的 6 个样本中，TMD 解释了不到 30%的组织弹性模量变异。组织硬度的结果相似。
组织矿物质密度是组织弹性模量的不完全替代物。需要考虑其他材料特性，以更全面地预测组织弹性模量的区域性变化。
