Abstract: Abstract：Objective To investigate biomechanics of proximal femoral nail anti-rotation (PFNA) with different entry points in the treatment of lateral wall fracture of femoral intertrochanteric fracture by finite element method. Methods Based on CT data of the hip of volunteers, three-dimensional model of right femur was extracted and optimized by Mimics and Geomagic software. Then, three A models (crushed lateral femoral wall and completed medial femoral wall) and three B models (crushed lateral femoral wall and medial femoral wall) were obtained by assembling different entry points with PFNA model in SolidWorks software and simulating different fracture lines of lateral wall. All the six models were imported into Abaqus software to set material properties and boundary conditions for transportation. The Von Mises cloud pictures of the model were calculated and viewed. Results In model A, the upper entry of the lateral wall formed stress concentration, the middle showed largest displacement and the bottom showed uniform stress distribution and smaller displacement. In model B, the upper entry of the lateral wall showed larger displacement, the middle showed largest stress concentration and the bottom showed smaller stress dispersion and displacement. Conclusion PFNA, which is selected the bottom entry of lateral femoral wall, has the best biomechanical effect in the treatment of lateral wall fracture of femoral intertrochanteric fracture.

Key words: proximal femoral nail antirotation, the entry point, fractured lateral wall femoral, femoral intertrochanteric fracture, biomechanics