[Prediction of bone strength using a CT based finite element method]

Hip fractures are the most serious complication of osteoporosis and have been recognized as a major public health problem. In elderly persons, hip fractures occur as a result of increased fragility of the proximal femur due to osteoporosis. It is essential to precisely quantify the strength of the proximal femur in order to estimate the fracture risk and plan preventive interventions. Computed tomography (CT)-based finite element analysis could possibly achieve precise assessment of the strength of the proximal femur. We have developed a three dimensional simulation model that could accurately predict the strength and surface strains of the proximal femur using a CT-based finite element method. The axial CT scans of the proximal femora were obtained with a calibration phantom, from which the 3D finite element models were constructed. Materially nonlinear finite element analyses were performed. The yield and fracture loads were calculated, while the sites where elements failed and the distributions of the principal strains and stresses were determined. The simulation is patient specific and could provide us of a useful tool to evaluate fracture risk in patients with osteoporosis. The technology utilized in this method would make a rapid progress in accordance with the progress of both imaging and computer technologies and much more precise prediction of the fracture risk will be realized in the near future.