Correlation of the mechanical and structural properties of trabecular bone assessed by wave propagation and imaging methods

This study aimed to assess the correlation of the location- and direction-dependent mechanical and structural properties of trabecular bone using the wave propagation and imaging methods and to propose a non-invasive approach for the assessment of the quality of trabecular bone. Two bovine femur trabecular bone specimens were prepared and tested using the Rayleigh wave propagation tests and CT-scan imaging. The elastic modulus of the specimens was estimated in different regions of interest (ROIs) and wave propagation directions by the solution of the presented Rayleigh wave propagation model. The structural parameters of the specimens were also obtained via the processing of CT-scan images for all of the tested ROIs and directions. The estimated elastic modulus was in the range between 321and 1322 MPa for different ROIs and directions, showing significant heterogeneity and anisotropy of the bone specimens. The Pearson correlation and linear regression analyses were carried out between the obtained mechanical and structural properties, which revealed that the elastic modulus decreased with the trabecular separation and increased with the trabecular thickness and bone volume fraction. A semi-empirical relation was developed to obtain the elastic modulus of trabecular bone using the structural parameters obtained from imaging or vice versa.