The application of 3-D X-ray microtomography with FEM analysis for trabecular bone/cement interface

Recently, microfinite element techniques based on high-resolution images have been introduced that allow modeling of trabecular bone structures since 3-D cone beam tomographic system was developed. Although microtomographic system has been paid much attraction for microstructure study, the interface between each other objects is not completely. Many published studies with FEM analysis suggested approximately assumed models of the interface for the application of biomechanical study. Therefore, mechanical failure was dependent on simple interface models assumed by the experiment and was predicted with FEM analysis. For FEM analysis with the real structure and interface, we obtained 3D cone beam microtomography of trabecular bone/cement of which the failure is considered to be an important cause of aseptic loosening of total hip replacements in orthopedic implants. The sample was manufactured by implanting cement in a pig hip bone and the system was composed of microfocusing X-ray tube, CMOS image sensor and microprecision motor. In case of microtomographic imaging trabecular bone/cement, it has white-out appearance due to low contrast nature with low energy X-ray. Therefore the multicriterion method for region and volume was applied to the segmentation of white-out appearance. The segmented data was used for FEM analysis as determining node of hexahedron meshing from it. The results of this paper show that the interface of trabecular bone/cement correctly can be distinguished by multicriterion method and the finite element modeling using microtomography can be used for predicting the failure mechanism of the interface with FEM analysis.