三种固定方式修复胫骨平台后外侧骨折的生物力学比较

背景：胫骨平台后外侧骨折修复方案包括后侧钢板螺钉、外侧钢板螺钉和前后拉力螺钉内固定；选择何种内固定方法主要是靠医师的临床经验，研究结果也大多是临床报道，缺乏力学实验的依据。目的：从生物力学角度比较外侧钢板螺钉组、后侧钢板螺钉组、前后拉力螺钉组3种固定方式修复胫骨平台后外侧骨折的生物力学变化。方法：采用6具成年男性防腐尸体胫骨标本共12个进行干骺端骨密度测定。电动摆锯建立胫骨平台后外侧1/2骨折模型，模型随机分3组进行前后拉力螺钉固定、外侧钢板螺钉固定、后侧钢板螺钉固定。利用有限元法和生物力学方法在250，500，1000 N的轴向载荷下测试骨折块的轴向位移值及最大位移值分布区。结果与结论：3组标本干骺端平均骨密度差异无显著性意义（P〉0.05）。在轴向载荷为250 N时，有限元实验中骨折块的位移值，前后拉力螺钉组最小，为0.013521 mm；后侧钢板螺钉组居中，为0.016991 mm；外侧钢板螺钉组最大，为0.138200 mm，在500，1000 N时情况类似。实验生物力学结果显示，前后拉力螺钉组的位移值明显小于外侧钢板螺钉组和后侧拉力螺钉组（P〈0.05）；后侧钢板螺钉组与外侧钢板螺钉组比较差异无显著性意义（P〉0.05），两种测试方法最大位移值分布区域都在近侧胫腓关节交界区。提示在生物力学稳定性方面，前后拉力螺钉组最具优势，外侧钢板螺钉组较差。临床可以考虑将前后拉力螺钉固定作为修复胫骨平台后外侧骨折的首选方案。

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

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