Biomechanical analysis of different lengths of INTERTAN in the treatment of AO31A2.3 fractures: A finite element study

Objective

To compare the biomechanical performance of different lengths of INTERTAN intramedullary nails (180 mm, 200 mm, 240 mm, 320 mm) in the treatment of AO31A2.3 intertrochanteric fractures through finite element analysis, providing a theoretical basis for the selection of clinical internal fixation methods.

Methods

Based on CT images of healthy volunteers, three-dimensional models of the femur and AO31A2.3 intertrochanteric fracture were constructed using Mimics, Geomagic Studio, and Creo 5.0 software, and finite element analysis was performed using Abaqus software. The stress distribution, stress-strain distribution at the fracture site, displacement, and overall deformation of the femur were simulated under three gait conditions: normal standing, slow walking, and descending stairs.

Results

There were significant differences in the overall displacement of the femur, the stress of the internal fixation, and the stress at the fracture site among INTERTAN internal fixations of different lengths. However, there was no significant difference in the strain at the fracture site. Compared with the 180-mm-long internal fixation, the 320-mm-long INTERTAN performed better in terms of the overall deformation of the femur and stress dispersion. The stress of the internal fixation decreased by 2.13 %–8.68 %, the anti-deformation ability increased by 0.53 %–4.86 %, and the stress at the fracture ends decreased by 0.56 %–3.33 %, indicating better biomechanical stability.

Conclusion

For AO31A2.3 intertrochanteric fractures, the 320 mm INTERTAN nail demonstrates superior performance in minimizing femoral deformation and fixation failure risk, which makes it the recommended choice for clinical use.