Finite Element Analysis of PFNA and PFNA Combined with Locking Plate in Treatment of Femoral Intertrochanteric Fracture with Lateral Wall Fracture

Abstract

Purpose: The biomechanical characteristics of Proximal Femoral Nail Antirotation (PFNA) and PFNA combined with Proximal Humerus Locking Plate (PHLP) in treatment of femoral intertrochanteric fracture with lateral wall fracture were compared by finite element analysis, and the biomechanical strength, stress and displacement distribution of the two internal fixation methods were compared. Methods: A healthy middle-aged female patient was selected. According to the femur CT scan data, the three-dimensional finite element models of the femur, PFNA, and PHLP were established .The simulated AO classification was 31-A3.3 femoral intertrochanteric fracture, and the two internal fixation assembly models of PFNA and PNFA+PHLP were established. The von mises stress distribution and displacement distribution nephograms of the two internal fixation models were observed when the same load was applied on the two models under the dynamic and static status. Result: Compared with PFNA fixation, PFNA+PHLP fixation reduced the maximum von mises stress by about 40%, while the maximum displacement changed little. The stress at the fracture end and the main nail position decreased, with a noticeablereduction of about 40% at the main nail. The Von Mises stress of the femoral head, femoral neck, medial, wall and spiral blade changed little. The total displacement of the femoral head, femoral neck, lateral wall, and spiral blade of PFNA+PHLP fixation decreased insignificant. Conclusion: PFNA + PHLP internal fixation in the treatment of femoral intertrochanteric fracture with lateral wall fracture has higher fixation strength and more reasonable stress distribution than PFNA internal fixation.