Finite element analysis of a subtrochanteric fractured femur with dynamic hip screw, dynamic condylar screw, and proximal femur nail implants--a comparative study

Selection of the correct type of implant for fracture fixation has become a very interesting problem in the orthopaedic community. The present work studies the biomechanical behaviour of the femur with three different implant configurations for simple transverse subtrochanteric fracture and the intact femur using finite element analysis. The implants considered in this study are as follows: dynamic hip screw (DHS), dynamic condylar screw (DCS), and proximal femur nail (PFN). The modelling software Unigraphics and finite element simulation software ANSYS are used for the present analysis. The three implants are compared for deflection, stress, and strains. The simulation also includes modelling of the cortical defect near the fracture. An estimation of the critical depth of the cortical defect based on the von Mises stress is obtained using this study on the DHS implant. The displacement and principal stress on the proximal femur have been compared for all the implant models. The stresses on the cortical screws for DCS and DHS implants have also been compared. The result shows that the DHS and DCS implants behave in a similar way to the intact femur compared with the PFN implant.