Biomechanical comparison of three fixation methods in the repair of posterolateral tibial plateau fracture

Zhang Yan; Liang Xu; Fan Xin-bin; Shao Jin; Liu Yue; Ye Wei-guang; Wu Liang; Yang Tie-yi; Gong Lu-lu

doi:10.3969/j.issn.2095-4344.2014.31.016

Abstract：BACKGROUND:Repair programs of posterolateral tibial plateau fracture included posterior plate screws, lateral plate screw and anterior and posterior lag screw fixation. To choose which fixation methods depends on clinical experiences of physicians. Study results are mainly clinical reports, and lack of mechanical evidence. <br> OBJECTIVE:To compare biomechanical changes in three fixed manners (lateral plate screw group, posterior plate screw group and anterior and posterior lag screw group) in the repair of posterolateral fracture of tibial plateau from the angle of biomechanics. <br> METHODS:A total of tibial specimens of six adult male antisepsis corpses (12 samples) were used for measuring bone mineral density of metaphysis. 1/2 posterolateral tibial plateau fracture model was established by electric pendulum saw. The model was randomly divided into three groups:lateral plate screw group, posterior plate screw group and anterior and posterior lag screw group. Finite element method and biomechanics were used to test axial displacement value and the maximal displacement distribution area under the axial loads of 250, 500, and 1 000 N. <br> RESULTS AND CONCLUSION:There was no significant difference in average bone density in three groups of metaphysis (P>0.05). The minimum axial displacement of the fracture fragments was in the anterior and posterior lag screw group (0.013 521 mm), fol owed by posterior plate screw group (0.016 991 mm), and the maximum was visible in the lateral plate screw group (0.138 200 mm) under 250 N load. Displacement value was similar to the 250 N under 500 and 1 000 N. According to the results of biomechanics, displacement values of anterior and posterior lag screw was obviously less than the lateral plate screw group and posterior plate screw group (P<0.05). There was no significant difference between the lateral plate screw group and posterior plate screw group (P>0.05). The maximal displacement distribution area was proximal tibiofibular joint border zone in two methods. These data indicated that the biomechanical stability was most advantageous in the anterior and posterior lag screw group, and poorest in the lateral plate screw group. In the clinic, anterior and posterior lag screw fixation can be used as a first choice for repair of posterolateral tibial plateau fracture.