三种内固定方式固定胫骨平台后外侧骨折的生物力学研究

目的探讨胫骨平台后外侧骨折合理有效的内固定方式。方法制作成年男性尸体胫骨平台后外侧骨折模型12个,随机平均分为3组,分别使用前侧6.5 mm拉力螺钉、胫骨平台外侧L型4.5 mm解剖锁定钢板、后侧T型3.5 mm锁定钢板固定。对标本模型进行轴向加压250、500、750、1000 N,检测其轴向位移及应力。结果在相同应力下,前侧螺钉组轴向Y轴位移最小,分别与外侧钢板组和后侧钢板组存在显著差异,而外侧钢板组与后侧钢板组之间Y轴位移没有显著差异;前侧螺钉组在标识点的应力分布最为均衡。结论在胫骨平台后外侧骨折的固定中,前侧螺钉能够有效增加轴向稳定,骨折块周围应力分布均衡,是一种有效的力学固定方式,外侧钢板在横向的稳定性控制上具有一定优势,后侧钢板对于后方需要复位的平台骨折具有一定价值。

Biomechanical study on three types of internal fixation methods for posterolateral fracture of the tibial plateau

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.