1. Department of Engineering Mechanics, Jilin University, Changchun (130022), People's Republic of China;
Int J Med Sci. 2013 Sep 7;10(11):1560-9. doi: 10.7150/ijms.6611. eCollection 2013.
The aim of this study was to investigate the relationship between microstructural parameters, material distribution, and mechanical properties of sheep tibia at the apparent and tissue levels during the fracture healing process. Eighteen sheep underwent tibial osteotomy and were sacrificed at 4, 8, and 12 weeks. Radiographs and micro-computed tomography (micro-CT) scanning were taken for microstructural assessment, material distribution evaluation, and micro-finite element analysis. A displacement of 5% compressive strain on the longitudinal direction was applied to the micro-finite element model, and apparent and tissue-level mechanical properties were calculated. Principle component analysis and linear regression were used to establish the relationship between principle components (PCs) and mechanical parameters. Visible bony callus formation was observed throughout the healing process from radiographic assessment. Apparent mechanical property increased at 8 weeks, but tissue-level mechanical property did not increase significantly until 12 weeks. Three PCs were extracted from microstructural parameters and material distribution, which accounted for 87.592% of the total variation. The regression results showed a significant relationship between PCs and mechanical parameters (R>0.8, P<0.05). Results of this study show that microstructure and material distribution based on micro-CT imaging could efficiently predict bone strength and reflect the bone remodeling process during fracture healing, which provides a basis for exploring the fracture healing mechanism and may be used as an approach for fractured bone strength assessment.
本研究旨在探讨绵羊胫骨在骨折愈合过程中表观和组织水平的微观结构参数、材料分布与力学性能之间的关系。18 只绵羊接受胫骨切开术，并在第 4、8 和 12 周时被处死。进行 X 射线和微计算机断层扫描（micro-CT）扫描以进行微观结构评估、材料分布评估和微有限元分析。对微有限元模型施加 5%纵向压缩应变的位移，并计算表观和组织水平的力学性能。采用主成分分析和线性回归建立主成分（PC）与力学参数之间的关系。从放射学评估来看，整个愈合过程中都观察到可见的骨痂形成。8 周时，表观力学性能增加，但直到 12 周时，组织力学性能才显著增加。从微观结构参数和材料分布中提取了三个主成分，占总变异的 87.592%。回归结果表明，PC 与力学参数之间存在显著关系（R>0.8，P<0.05）。本研究结果表明，基于 micro-CT 成像的微观结构和材料分布可以有效地预测骨强度，并反映骨折愈合过程中的骨重塑过程，为探索骨折愈合机制提供了依据，并可能作为评估骨折骨强度的一种方法。
