Biomechanical Analysis of Proximal Femur Bionic Nail in Treating Intertrochanteric Fractures with Different Lateral Wall Classifications: A Finite Element Study

Background This study employed finite element analysis to compare the biomechanical stability of the Proximal Femoral Nail Antirotation (PFNA) and the Proximal Femur Bionic Nail (PFBN) in treating intertrochanteric fractures with different lateral wall classifications. Methods CT scan data from a healthy 45-year-old male were used to construct three-dimensional models of the proximal femur. Using Mimics 21.0, Geomagic Studio, SolidWorks 2017, and ANSYS Workbench, models of PFNA and PFBN were assembled with AO/OTA 31-A1.2 (stable lateral wall), A2.2 (compromised lateral wall), and A3.3 (fractured lateral wall) intertrochanteric fracture types. The bone material properties were set to simulate osteoporosis. ANSYS software was used to simulate standing and walking conditions by applying loads of 700 N (1× body weight) and 1995 N (4× body weight), respectively. The following parameters were analyzed: maximum displacement of the proximal femur, maximum displacement of the internal fixation, maximum stress distribution in the proximal fracture fragment, maximum stress distribution in the internal fixation, and femoral neck varus angle. Results 1.Across all three lateral wall classifications, the PFBN group exhibited significantly lower values for maximum displacement of the proximal femur, maximum displacement of the internal fixation, maximum stress in the internal fixation, and maximum stress in the proximal fracture fragment compared to the PFNA group under both loading conditions. 2.In the A3.3 fracture model, both PFNA and PFBN groups showed higher values for all measured parameters compared to the A1.2 and A2.2 models. 3. In the PFNA group, the maximum stress in the proximal fracture fragment was concentrated at the interface between the fracture surface and the helical blade. In contrast, the PFBN group exhibited stress concentration at the junction of the tension and compression screws, effectively reconstructing the physiological stress distribution of the proximal femur. Conclusion Under both loading conditions, the PFBN demonstrated superior biomechanical stability for intertrochanteric fractures across all lateral wall classifications. This advantage stems from the PFBN's ability to more accurately reconstruct the normal biomechanical pivot point of the hip joint, making it a more effective option for treating intertrochanteric fractures compared to the PFNA.