Multi-level patient-specific modelling of the proximal femur. A promising tool to quantify the effect of osteoporosis treatment

Abstract

Preventing femoral fractures is an important goal in osteoporosis research. In order to evaluate a person's fracture risk and to quantify response to treatment, bone competence is best assessed by bone strength. Finite-element (FE) modelling based on medical imaging is considered a very promising technique for the assessment of in vivo femoral bone strength. Over the past decades, a number of different FE models have been presented focusing on the effect of several methodological aspects, such as mesh type, material properties and loading conditions, on the precision and accuracy of these models. In this paper, a review of this work is presented. We conclude that moderate to good predictions can be made, especially when the models are tuned to specific loading scenarios. However, there is room for improvement when multiple loading conditions need to be evaluated. We hypothesize that including anisotropic material properties is the first target. As a proof of the concept, we demonstrate that the main orientation of the femoral bone structure can be calculated from clinical computed tomography scans. We hypothesize that this structural information can be used to estimate the anisotropic bone material properties, and that in the future this could potentially lead to a greater predictive value of FE models for femoral bone strength.

Computational analyses of small endosseous implants in osteoporotic bone

“…Unfortunately, there is still no common agreement on how AJ Wirth et al Analyses of small endosseous implants in osteoporotic bone fabric should be defined for trabecular bone (Cowin, 1991;Luo and An, 1998). Additionally, it is also unclear as to what should be the size of the sub-regions to get a proper measure of fabric using appropriate continuum assumptions, in order to get a correct mechanical behavior of the entire bone (Lenaerts and Van Lenthe, 2009). All this makes the modeling of bone's material properties in a continuum representation challenging.…”

“…Most osteoporotic fractures occur in regions with a high content of trabecular bone, hence, the relatively complex material properties (Lenaerts and Van Lenthe, 2009;Morgan and Bouxsein, 2005) of bone have to be modeled adequately. The material properties of trabecular bone are strongly anisotropic, caused by a preferential orientation of the trabeculae.…”

Comparison of proximal femur and vertebral body strength improvements in the FREEDOM trial using an alternative finite element methodology

“…A few authors have reviewed the challenges of its patient-specific application [37][38][39][40]. A key parameter limiting accurate calculation of bone strength from CT images remains the accurate assessment of local BMD [41].…”

Confocal microscopy-based three-dimensional cell-specific modeling for large deformation analyses in cellular mechanics

“…At the organ scale, image-based finite element (FE) modeling is currently considered a state-of-the-art biomechanical research methodology, where typically, computed tomography or magnetic resonance imaging are employed to obtain a set of planar images used to reconstruct a three-dimensional (3D) organ (Pistoia et al, 2004;Linder-Ganz et al, 2007;Portnoy et al, 2008;Lenaerts and van Lenthe, 2009). The equivalent of this at a cellular scale could be confocal microscopy imaging, which allows obtaining a set of planar images for individual cells; however, image-based modeling has not yet been employed at a cell-scale for large deformation analyses.…”