胫骨平台后柱骨折钢板固定的三维有限元分析

目的]研究胫骨平台后柱骨折不同内固定模型在轴向载荷作用下平台位移、钢板应力的分布规律,探讨符合力学原理的最佳内固定及手术入路方式.方法]在有限元相关软件中建立胫骨平台后柱骨折模型,并分别建立胫骨平台后柱骨折四种钢板固定方式的有限元模型.设定边界及载荷条件,模拟体重60 kg的成人双足站立（250 N）、单足站立（500 N）、慢走（1000 N）、快走（1500 N）四种工况下胫骨平台后柱骨折四种固定方式下胫骨平台位移、应力分布及钢板螺钉承受应力情况.结果]在有限元软件中建立了形象逼真、接近临床实际的胫骨平台后柱骨折钢板固定三维有限元模型;四种固定模型在轴向载荷为500 N、1000 N、1500 N时,外侧钢板固定模型平台最大轴向位移都最大,内侧钢板固定模型较外侧钢板固定模型平台最大轴向位移值小,后侧钢板固定模型较内侧钢板固定模型平台最大轴向位移值小,双侧钢板固定模型平台最大轴向位移值最小;随着载荷增大,四种固定方式下钢板螺钉承受的应力值也随之增大.结论]利用有限元相关软件建立的胫骨平台后柱骨折有限元模型及钢板内固定有限元模型能有效模拟骨折真实情况,指导临床治疗.采用双侧钢板固定胫骨平台后柱骨折时的平台轴向位移最小,承担的应力最大,稳定性最好,是最可靠的固定方法;采用单一钢板固定,则后侧钢板固定胫骨平台后柱骨折时的平台轴向位移最小,承担的应力最大,稳定性最佳,固定最为牢靠.

Three-dimensional Finite Element Analysis of the Fixation of Posterior Column Fracture of Tibial Plateau with Plates and Screws

Objective]To research the platform displacement and the distribution of plate stress in different in-ternal fixation models of posterior column fracture of tibial plateau with axial load, and to explore the best internal fixation and operative approaches according with mechanics. Methods] The models of posterior column fracture of tibial plateau were established by using finite element relevant software. Finite element models of posterior column fracture of tibial plateau with four plate fixation ways were established respectively. The border and load condition were set. The platform displacement, stress distribution and the stress of plates and screws of tibial plateau with four fixation ways of posterior column fracture of tibial plateau simulating adults weighed 60kg with both legs stand-ing（250N）, one leg standing（500N）, slow walking（1000N） and fast walking（1500N） were analyzed. Results] Three-dimensional finite element models of posterior column fracture of tibial plateau which were iconic, vivid and near to clinical practice were established by using finite element software. When the axial load of four fixation rood els were 500N, 1000N and 1500N, the maximum axial deflection of the plateau of lateral plate fixation model was the greatest. The maximum axial deflection of the plateau of medial plate fixation model was less than that of the plateau of lateral plate fixation model. The maximum axial deflection of the plateau of posterior plate fixation model was less than that of the plateau of medial plate fixation model. The maximum axial deflection of the plateau of bilat-eral plate fixation model was the smallest. The stress of plates and screws with four fixation ways increased with the load. Conclusion] Finite element models of posterior column fracture of tibial plateau and internal fixation with the plate established by using finite element relevant software can effectively simulate the real fracture and guide clinical treatment. Bilateral plate fixation of posterior column fracture of tibial plateau has minimum axial deflection of plat-eau, maximum load stress and best stability, so it is most reliable fixation method. Simple posterior plate fixation of posterior column fracture of tibial plateau had minimum axial deflection of plateau, maximum load stress and best stability, so the fixation is the most stable.