The nature of fatigue damage in bone
The nature of fatigue damage in bone
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DOI：
10.1016/s0142-1123(00)00054-2
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发表时间：
2000-11-01
影响因子：
6
通讯作者：
Taylor, D
中科院分区：
文献类型：
--
作者：
Lee, TC;O'Brien, FJ;Taylor, D
骨在结构材料中是不寻常的，因为它是活的，能够自我修复。骨损伤引起的微损伤可以通过骨重建来修复，但如果损伤积累过快，或重建不足，则可能导致疲劳失效。疲劳被认为是导致应力性骨折和脆性骨折的原因，这两种骨折具有重要的临床意义。尽管如此，我们并不完全了解骨骼疲劳损伤的本质。人体肋骨切片，含有微裂纹染色碱性品红，连续切片和微裂纹识别和重建的三维使用计算机软件。微裂纹呈椭圆形，400 μ m长，100 μ m宽，典型的横观各向同性材料。结合钙离子的螯合剂被发现标记肋骨中的微裂纹，以及矿化骨表面和再吸收位点，这表明微裂纹是羟基磷灰石基质中的钙离子内衬的不连续性。通过刮擦牛骨样品表面暴露Ca2+离子，并依次用螯合剂标记。最佳的四种试剂顺序为：茜素、二甲酚橙子、钙黄绿素和钙黄绿素蓝。两种染料序列被用来区分预先存在的和测试引起的微损伤在牛样品疲劳测试中的压缩和更长的序列标记的微裂纹生长。微裂纹尺寸可用于计算应力强度值，并与疲劳试验数据一起，可帮助理论模型预测骨中的疲劳失效。(C)2000爱思唯尔科技有限公司版权所有。
Bone is unusual among structural materials as it is alive and capable of self-repair. Fatigue-induced microdamage is repaired by bone remodelling, but if damage accumulates too quickly, or remodelling is deficient, fatigue failure may result. Fatigue is thought to contribute to both stress and fragility fractures which are of major clinical importance. Despite this, we do not fully understand the nature of fatigue damage in bone. Human rib sections, containing microcracks stained with basic fuchsin, were serially sectioned and microcracks identified and reconstructed in three dimensions using computer software. Microcracks were elliptical in shape, 400 mum long and 100 mum wide, typical of a transversely isotropic material. Chelating agents which bind Ca2+ were found to label microcracks in rib, as well as mineralising bone surfaces and resorption sites, suggesting that microcracks are Ca2+ ion-lined discontinuities in the hydroxyapatite matrix. Ca2+ ions were exposed by scratching the surface of bovine bone specimens and labelled with chelating agents in sequence. The optimal four agent sequence was: alizarin, xylenol orange, calcein and calcein blue. Two dye sequences were used to differentiate between pre-existing and test-induced microdamage in bovine samples fatigue tested in compression and longer sequences labelled microcrack growth. Microcrack dimensions can be used to calculate stress intensity values and, together with fatigue test data, can aid theoretical models to predict fatigue failure in bone. (C) 2000 Elsevier Science Ltd. All rights reserved.