S022025 髄内釘の開発・評価におけるFEM解析と力学試験の相互関係について

Abstract

Today the development of most orthopedic implants makes great use of Mechanical testing and FEM analysis. At Mechanical testing however, it is difficult to know about the conditions within implant and results are prone to error. Additionally, in FEM analysis, results can change even when something as simple as boundary conditions are chosen incorrectly. In this study, the evaluation of mechanical and FEM analysis using an intertrochanteric femur fracture model was performed. An intertrochanteric femur fracture fixed with a femoral nail was first designed in CAD software. The mechanical model was tested under single compression and the displacement deviation between before and after compression was measured with a contactless 3D-Scan. In the FEM analysis, constraint conditions were defined similar to Mechanical testing conditions. Displacement was used to compare the results. The deformation method of the mechanical test was similar to that of the FEM analysis. However, displacement values of the FEM analysis were twice than the mechanical displacement. The elastic modulus of the inner urethane foam duplicates cancellous bone changes because the applied loads crumpled air holes within the urethane foam. The results of the FEM analysis will differ from Mechanical testing due to the fact that the elastic modulus used for FEM calculations is non-linear.