ABSTRACT
Objective To investigate a reasonable and effective internal fixation method for posterolateral fracture of the tibial plateau. Methods Specimens of the tibial plateau with posterolateral fracture made from 12 adult male cadavers were randomly and evenly divided into 3 groups, and fixed by anterior 6.5 mm lag screw, lateral 4.5 mm L-shape plate, posterior 3.5 mm T-shape plate, respectively. All the specimens were loaded in turn by stress of 250, 500, 750, 1 000 N, and the corresponding axial displacement and stress were measured. Results Under the same stress, the Y-axial displacement of the anterior lag screw group was the smallest, showing a significant difference with the lateral plate group and the posterior plate group, while there was no significant difference between the lateral plate group and the posterior plate group in the Y-axial displacement. The stresses on marked points in the anterior lag screw group were evenly distributed. Conclusions For fixation of isolated posterolateral fractures of the tibial plateau, the anterior 6.5 mm lag screw can effectively increase the axial stability and balance the stress distribution around the fracture block, indicating it is an effective method for mechanical fixation. The lateral plate has certain advantage in lateral stability control, while the posterior plate has certain value to reduction of the posterior tibia plateau fracture.
ABSTRACT
Objective To investigate the differences in biomechanical properties of 3 internal fixation patterns(the lateral plate and screw group, the rear plate and screw group, and the front and rear lag screw group) for treating posterolateral tibial plateau fracture under different axial loads. Methods Based on CT data of the tibial plateau, the entity model of 1/2 and 1/4 posterolateral tibial plateau fracture with 3 internal fixations were established and meshed to analyze force status of the fracture models with 3 internal fixations under different axial loads. ResultsUnder the axial load of 1 kN, for the 1/2 posterolateral tibial plateau fracture model, the displacements of the fracture fragments in the lateral plate and screw group, the rear plate and screw group, and the front and rear lag screw were 552.082, 67.964, 54.085 μm, respectively, and the stresses on the fixation device were 306.745, 231.844, 73.047 MPa, respectively. For the 1/4 posterolateral tibial plateau fracture model, the displacements in the three groups above were 416.072, 302.107, 150.639 μm, respectively, and the stresses on the fixation device were 306.673, 208.467, 73.607 MPa, respectively. Both the displacements of the fracture fragments and the stresses on the fixation device increased correspondingly under the axial load of 1.5 kN, and the trend of the data was similar to that under the axial load of 1 kN. Conclusions The results from the fracture models with 3 internal fixation patterns show that the front and rear lag screw group has a superior biomechanical stability under two different axial loads, and the similar mechanical properties can be achieved in the rear plate and screw group. Therefore, the front and rear lag screws will be preferred to treat posterolateral tibial plateau fracture with less obvious displacement in clinic.