Relationship between apparent elastic modulus and microstructural parameters of senile vertebral trabecular bone

The aim of this paper is to investigate the influence of microstructural parameters of senile vertebral cancellous bone on the apparent elastic moduli of three orthogonal directions. Thirty-six cubic regions of interest were obtained from six L4 vertebral bodies with the ages of 60-70. After scanned by a Micro-Computed Tomography (Micro-CT) system, seven 3D microstructural parameters were derived. Micro-finite element models were built to simulate axial compression test along three orthogonal directions. It was shown that strong correlations existed among the 7 microstructural parameters. Principal component analysis (PCA) was performed to extract 3 independent principal components (PCs), which represented bone "quality", bone quantity & microarchitecture, and trabecular thickness, respectively. The apparent elastic moduli on the three orthogonal directions were significantly correlated with these three PCs. Compared with using bone mass alone, the three PCs could better explain the variance of the apparent elastic moduli on the three orthogonal directions.