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Relationship between microstructure, material distribution, and mechanical properties of sheep tibia during fracture healing process.

Gao J, Gong H, Huang X, Fang J, Zhu D, Fan Y - Int J Med Sci (2013)

Bottom Line: 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).

View Article: PubMed Central - PubMed

Affiliation: 1. Department of Engineering Mechanics, Jilin University, Changchun (130022), People's Republic of China;

ABSTRACT
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.

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Region for microstructural evaluation and μFEA. (A - Callus without plate and the region for μFEA (between the two holes across the fracture gap); B - 3D region for qualitative evaluation of callus, which was built from 2D micro-CT images; C - μFE model and boundary conditions).
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Figure 2: Region for microstructural evaluation and μFEA. (A - Callus without plate and the region for μFEA (between the two holes across the fracture gap); B - 3D region for qualitative evaluation of callus, which was built from 2D micro-CT images; C - μFE model and boundary conditions).

Mentions: Then, quantitative analysis of the callus microstructure was performed by a micro-CT system (Skyscan 1076, Skyscan, Belgium) operated at 70 KV and 142 μA with Al 1.0 mm filter. The spatial resolution for specimen scanning was set to 38 μm. Micro-CT images of the callus were obtained for evaluating the microstructural parameters and μFEA (Figure 2). The following measures of callus structure and composition were evaluated from the micro-CT data for each specimen: bone mineral density (BMD), bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), and trabecular separation (Tb.Sp) 26.


Relationship between microstructure, material distribution, and mechanical properties of sheep tibia during fracture healing process.

Gao J, Gong H, Huang X, Fang J, Zhu D, Fan Y - Int J Med Sci (2013)

Region for microstructural evaluation and μFEA. (A - Callus without plate and the region for μFEA (between the two holes across the fracture gap); B - 3D region for qualitative evaluation of callus, which was built from 2D micro-CT images; C - μFE model and boundary conditions).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3775115&req=5

Figure 2: Region for microstructural evaluation and μFEA. (A - Callus without plate and the region for μFEA (between the two holes across the fracture gap); B - 3D region for qualitative evaluation of callus, which was built from 2D micro-CT images; C - μFE model and boundary conditions).
Mentions: Then, quantitative analysis of the callus microstructure was performed by a micro-CT system (Skyscan 1076, Skyscan, Belgium) operated at 70 KV and 142 μA with Al 1.0 mm filter. The spatial resolution for specimen scanning was set to 38 μm. Micro-CT images of the callus were obtained for evaluating the microstructural parameters and μFEA (Figure 2). The following measures of callus structure and composition were evaluated from the micro-CT data for each specimen: bone mineral density (BMD), bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), and trabecular separation (Tb.Sp) 26.

Bottom Line: 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).

View Article: PubMed Central - PubMed

Affiliation: 1. Department of Engineering Mechanics, Jilin University, Changchun (130022), People's Republic of China;

ABSTRACT
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.

Show MeSH
Related in: MedlinePlus