Comparison of biomechanics between two different external fixation methods in the treatment of A1b tibial fractures based on finite element analysis.

OBJECTIVE

To compare the biomechanical stability between two different external fixation methods (locked steel plates versus external fixation frame) for the treatment of A1b tibial fractures based on finite element analysis, and to provide theoretical reference for clinical application.

METHODS

Based on CT data of the left tibia from a healthy male volunteer, a normal three-dimensional (3D) tibial model was constructed using modeling software, which was further derived into a A1b tibial fracture model. Then, On the basis of the fracture model constructed above, the finite element models of locking compression plate and unilateral external fixator were fixed respectively. Further, 4 different test conditions (i.e., 4-point bending, axial compression, clockwise torsion, and counterclockwise torsion) were simulated under the same loading and constraint conditions for both models, in order to comparatively evaluate the equivalent peak stress and peak overall displacement of the fracture site between the two methods.

RESULTS

From the experimental data corresponding to the maximum load under 4 different test conditions, it was found that the peak stress of tibia and the equivalent peak stress of fractured tibia with external fixation was roughly ranged 49.16-269.59 MPa and 34.99-559.58 MPa in the two fixation methods under various test conditions. Overall, external fracture fixation with locked steel plates showed a greater equivalent peak stress and a smaller peak overall tibial displacement than that with external fixation frame did.

CONCLUSIONS

Locked steel plates may be superior external fixation frame in terms of biomechanical properties in the treatment of A1b tibial fractures, and can be used as an alternative option for patients who cannot tolerate external fixation frame.