Contribution of Micro-Architecture in Elastic Modulus of Trabecular Bone

Research Category: 
Quasi-3D cell mechanics

It is widely believed the detailed microstructure of trabecular bone such as the bone volume fraction (the ratio of volume of bone tissue to the overall bone volume), trabecular orientation and connectivity (the extent of trabecular connections) is important in governing the mechanical properties and failure of trabecular bone. However, it is not clear the relative contribution of trabecular bone micro-architecture such as trabecular connectivity, trabecular bone type (rod vs. plate), to trabecular bone strength, in addition to bone volume fraction. A new topology preserving skeletonization and classification technique combined with micro computed tomography (µCT) image based finite element (FE) model enables the analysis of the relationship between the trabecular micro-architecture and mechanical properties of trabecular bone. The unique feature of this technique is the preservation of topological properties (rod-like and plate-like structures, connectivities and cavities) while without maintaining bone volume fraction. In addition, rod-like or plate-like trabeculae can be independently recovered from the skeleton structure and their contribution to mechanical properties of trabecular bone can be quantitatively examined. Therefore, the focus of this study is to characterize quantitatively the contribution of micro-architecture to mechanical properties of trabecular bone using image based finite element analysis technique.

The skeletonized trabecular bone µCT image accurately preserves the micro-architecture of trabecular bone but with minimal bone volume information.

There is a significant correlation between Young¡¯s modulus of the skeletonized and full voxel models

When rod-like trabeculae are recovered, a minimal recovery of mechanical properties of trabecular bone is resulted as indicated by the proportional coefficient of the linear regression as well as the coefficient of correlation. However, when plate-like abeculae are recovered, almost full elastic modulus has been restored.

Related Publications
1. Liu XS, Sajda P, Saha PK, Wehrli FW, Guo XE, Skeleton Micro-Architecture Predicts Elastic Modulus of Trabecular Bone. 2004 Biomedical Engineering Society Annual Meeting , Philadelphia , PA , October 13-16, 2004 .
2. Liu XS, Saha PK, Wehrli FW, Sajda P, Guo XE, Contribution of Micro-architecture in Elastic Modulus of Trabecular Bone, Transactions of the 50th Annual Meeting of the Orthopaedic Research Society , Washington DC , February 20-23, 2005
3. Liu XS, Sajda P, Saha, PK, Wehrli FW, Guo XE (2006) Quantification of the Roles of Trabecular Microarchitecture and Trabecular Type in Determining the Elastic Modulus of Human Trabecular Bone, Jounal of Bone and Mineral Research, 21(10), pp.1608-17

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