Finite element analysis of anterograde and retrograde intramedullary nail for different areas of femoral shaft fractures / 中国组织工程研究

ABSTRACT

BACKGROUND:Intramedullary nail has achieved a good clinical result in the treatment of femoral shaft fractures,but some patients still have aseptic nonunion due to mechanical instability.The femur is the longest and largest bone in the human body,but there are few studies on whether the fracture of the femur has different biomechanical results in different areas and the influence of different inserting methods on the stability of fracture fragments in different areas. OBJECTIVE:To analyze the biomechanical characteristics of anterograde and retrograde intramedullary nails in the treatment of different areas of femoral shaft fractures,and to evaluate the best way of insertion to reduce the incidence of nonunion. METHODS:CT data of a healthy volunteer were selected to import into the software of Mimics 19.0 and Geomagic studio 2017 to extract and optimize the three-dimensional model of the right femur.The anterograde and retrograde intramedullary nail models were built with Solidworks 2017 software and assembled with femoral shaft fracture models at different fracture areas according to standard surgical techniques.The models were imported into Abaqus 2017 software in STEP format to set material attribute parameters,boundary conditions,load and submit calculation,and the results were viewed in the visualization module.Among them,the antegrade and retrograde intramedullary nails of the upper femoral shaft fracture were A1 and A2 models,B1 and B2 models in the middle segment,and C1 and C2 models in the lower segment. RESULTS AND CONCLUSION:(1)In models A1,B1 and C2,the overall stress distribution of the femur was more uniform,and the placement,the displacement and angle of the fracture site,and inversion angle of the proximal femoral bone fragment were smaller.(2)For the upper and middle femoral shaft fractures,the anterograde intramedullary nail has a better biomechanical effect.For lower femoral shaft fractures,a retrograde intramedullary nail is preferable.