Finite element analysis of unstable intertrochanteric fracture fixed with triangle proximal femoral nail

Hu Qun-sheng; Jiang Zi-wei; Huang Feng

doi:10.3969/j.issn.2095-4344.2016.48.011

Abstract：BACKGROUND:Proximal femoral nail antirotation (PFNA) and Asian PFNA (PFNA-II) are the most common internal fixation methods in the treatment of intertrochanteric fractures. But stress concentration and failure of internal fixation are stil inevitable. <br> OBJECTIVE:To analyze the biomechanical behaviors of the unstable intertrochanteric fracture fixed with the new designed triangle proximal femoral nail and to testify its feasibility by compared with PFNA-II. <br> METHODS:Three-dimensional finite element model of proximal femur was established by using CT data of femur. Then the Evans IV femoral intertrochanteric fracture was established, fol owed by fixed with triangle proximal femoral nail and PFNA-II, respectively. The stress distribution and biomechanical stability under the same load were compared between two nails. <br> RESULTS AND CONCLUSION:(1) The stress concentration of the two nails was both located at the junction of the screw blade and the main nail. (2) The maximum stress of PFNA-II and proximal femoral nail was 214 and 196.2 MPa, respectively. The displacement of PFNA-II model was significantly larger than that of the triangular proximal femoral nail (5.37 mm versus 5.18 mm). (3) To conclude, for Evans IV intertrochanteric fracture, the triangle proximal femoral nail is superiority to PFNA-II, showing the good fixation stability and low incidence of internal fixation failure, which al meet the treatment standards.