Cancellous bone mechanical properties from normals and patients with hip fractures differ on the structure level, not on the bone hard tissue level
Cancellous bone mechanical properties from normals and patients with hip fractures differ on the structure level, not on the bone hard tissue level
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DOI：
10.1016/s8756-3282(02)00693-2
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发表时间：
2002-05-01
期刊：
影响因子：
4.1
通讯作者：
Huiskes, R
中科院分区：
文献类型：
--
作者：
Homminga, J;McCreadie, BR;Huiskes, R
骨质疏松症目前被定义为低骨量。然而，导致断裂的脆性来源尚未得到充分描述。特别是，骨组织特性和结构对骨折风险或发生率的贡献知之甚少。在早期的实验研究中，发现与年龄和密度匹配的对照材料相比，来自骨折患者股骨头的松质骨的结构各向异性显著增加（Ciarelli等人，J Bone Miner Res 15：32-40; 2000）。对该研究中的松质骨样本子集进行压缩测试和微观有限元分析，计算硬组织力学性能和表观（宏观）力学性能。对照组的组织模量为10.0 GPa（SD 2.2），骨折组为10.8 GPa（SD 3.3）（不显著）。无论是表观屈服应变，高度应变组织的百分比，或表观屈服应力和表观弹性模量之间的关系没有差异。因此，组织屈服特性不太可能存在差异。在表观水平上，骨折组的横向刚度显著降低，导致机械各向异性增加。这些变化表明，骨折组的骨对主要载荷轴“过度适应”，代价是横向方向的脆性。我们的结论是，有骨质疏松性骨折史的人骨组织并不脆弱。结构和力学各向异性单独使他们的骨在非主要载荷方向上较弱。(C)2002年，Elsevier Science Inc. All rights reserved.
Osteoporosis is currently defined in terms of low bone mass. However, the source of fragility leading to fracture has not been adequately described. In particular, the contributions of bone tissue properties and architecture to the risk or incidence of fracture are poorly understood. In an earlier experimental study, it was found that the architectural anisotropy of cancellous bone from the femoral heads of fracture patients was significantly increased compared with age- and density-matched control material (Ciarelli et al., J Bone Miner Res 15:32-40; 2000). Using a combination of compression testing and micro-finite element analysis on a subset of cancellous bone specimens from that study, we calculated the hard tissue mechanical properties and the apparent (macroscopic) mechanical properties. The tissue modulus was 10.0 GPa (SD 2.2) for the control group and 10.8 GPa (SD 3.3) for the fracture group (not significant). There were no differences in either the apparent yield strains, percentages of highly strained tissue, or the relationship between apparent yield stress and apparent elastic modulus. Hence, a difference in the tissue yield properties is unlikely. At the apparent level, the fracture group had a significantly decreased transverse stiffness, resulting in increased mechanical anisotropy. These changes suggest that bone in the fracture group was "overadapted" to the primary load axis, at the cost of fragility in the transverse direction. We conclude that individuals with a history of osteoporotic fractures do not have weaker bone tissue. Architectural and mechanical anisotropy alone renders their bone weaker in the nonprimary loading direction. (C) 2002 by Elsevier Science Inc. All rights reserved.