Finite Element Analysis Of Different Configurations Cannulated Compression Screws Internal Fixation In The Treatment Of Pauwels Ⅲ Type Femoral Neck Fracture

Objective : In the present study,we evaluated the mechanical outcome of diferent confgurations of cannulated compression screws for the fxation of Pauwels type Ⅲ femoral neck fracture.Methods : Pauwels type Ⅲ of femoral neck fracture was created in three-dimensional software and the models of cannulated compression screws were constructed using ProEngineer5.0 sofware.The screw distribution is equilateral triangle 、 inverted triangle 、anterior triangle、 posterior triangle and vertical distributionand.then five fxation systems were assembled to the fracture models.Ansys13.0 sofware was used to perform the process of finite element analysis.Values of stress distribution,maximum stress,model principal strains of proximal fragment were recorded.Results: Stress of cannulated compression screws was intensely focused on the middle area of the screw near the fragment of each group.Inverted triangle model showed the highest peak stress on screws under diferent phases of load.Each screw dispersed some stresses,but at least one underwent the peak stress.Fracture model fixed by inverted triangle confguration showed the lowest volume of yielding strain in the proximal fragment.Conclusion: Our study indicated that different cannulated compression screws fxation confgurations for the unstable femoral neck fractures showed the different mechanical efficiency.Inverted triangular confguration showed the mechanical advantage and being less likely to cutout.