不同进针角度张力带对髌骨C1型骨折治疗的有限元分析

Finite Element Analysis of Patellar C1 Fracture Treated by Tension Band with Different Needle Insertion Angles

目的建立髌骨C1型骨折钛缆张力带内固定的三维有限元模型,并对所建模型进行有限元力学分析。方法选择1例成年男性志愿者行下肢薄层CT扫描,将图像数据通过软件建立髌骨几何模型,利用软件中的分割功能模拟髌骨C1型骨折,利用软件中的扫描功能生成2根张力带别针和“8”字形钛缆,建立三维C1型骨折钛缆张力带内固定模型,模拟屈膝90°髌股关节作用力600N进行有限元分析,分析其位移及变形特点。结果a)骨折髌骨的位移:张力带别针平行置入比张力带别针成角度置入要小;b)骨折面压力:张力带平行的时候骨折面压力峰值大于成角度入针;c)骨折面的相对滑动距离:张力带别针平行置入时小于成角度置入。结论张力带别针平行置入要优于成角度置入,该结果与生物力学结果相符,有限元分析有助于了解不同角度张力带内固定髌骨骨折优劣,为进一步了解髌骨骨折治疗的疗效提供理论基础。

Objective To establish a three-dimensional finite element model for internal fixation of patellar C1 fracture with titanium cable tension band,and to analyze the finite element mechanics of the model. MethodsOne adult male volunteer was scanned by thin slice CT of lower extremity.The patella geometric model was established by image data through software.The patella C1 fracture was simulated by the segmentation function of software.Two tension band pins and “8” shaped titanium cable were generated by the scanning function of software.A three-dimensional tension band fixation model of C 1 fracture was established to simulate the 90 degree patellofemoral joint of flexion knee.Finite element analysis was carried out to analyze the displacement and deformation characteristics of the force 600N. Resultsa)Displacement of fracture patella:Parallel insertion of tension band pin was smaller than that of angular insertion of tension band pin;b)Pressure of fracture surface:When tension band was parallel,the peak pressure of fracture surface was larger than that of angular insertion;c)Relative sliding distance of fracture surface:When tension band pin was parallel,it is smaller than that of angular insertion. ConclusionParallel tension band pin placement is better than angular pin placement.The results are consistent with biomechanical results.Finite element analysis is helpful to understand the advantages and disadvantages of different angle tension band internal fixation for patellar fracture,and to provide a theoretical basis for further understanding the therapeutic effect of patellar fracture.