Comparison of two different fixation methods in treating fractures of Type 42A2 through finite element analysis

Abstract

Abstract Background At present, not all open fractures of Type 42A2 can be treated by external fixation stents, and it is inconvenient to use clinically, and external locking steel plates can be used as an alternative treatment for such patients, and the use is light and convenient. And there are few reports of finite element biomechanical analysis of external locking steel plates and external fixation brackets placed on the medial side of tibial fractures. In this study, the biomechanical properties of external locking steel plate and traditional external fixation bracket were compared by finite element method when fixing fracture of Type 42A2, which provided data support for clinical application of external locking steel plate fixation. Methods We established a fracture of Type 42A2 model using CT data of a volunteer, and constructed two external fixation models: external locking steel plate fixation and external fixation bracket. The fracture of Type 42A2 model and two external fixation models were assembled according to the common clinical fixation methods. Finally, the axial compression, four-point bending and clockwise torsion force of the maximum load were directly loaded into the mechanical software, and the stress distribution, stress peak and overall tibial displacement in the two sets of different external fixation models were observed and compared. Results Under the maximum load of four different experimental conditions (four-point bending, axial compression, clockwise torsion, counterclockwise torsion), the two sets of external fixation models mainly had obvious Von Mises stress concentrations in the junction between screw and tibia, screw and locking plate, self-tapping self-drilling needle and tibia, self-tapping self-drilling needle and external fixation frame, near the fracture end and near the cortical bone at the upper and lower ends of the tibia. The stress peak is about 26.67 MPa~558.77 MPa, all within the yield stress strength of titanium alloy. The peak displacement of the tibia in the external locking steel plate fixation model was smaller than that of the external fixation bracket model. In terms of structural stability, the external fixation effect of locking steel plate is better than that of single-sided external fixation. Conclusions When the external locking steel plate fixes the fracture of Type 42A2, it is not only lightweight and convenient, but also reduces the complications in the fracture healing process, and performs better in axial compression force, bending force and torsion resistance. From the finite element biomechanical analysis, the performance of the external locking steel plate is better than that of the traditional external fixation bracket in the treatment of fractures of Type 42A2, which can meet the needs of clinical external fixation applications.