BACKGROUND:Traditional distal femoral fixation plate screw breakage is relatively common. Designing good anatomical and attached fixation system is the key for clinical application. OBJECTIVE:To perform finite element analysis in two states of motion of the minimal y invasive distal femoral fixation system, compare stress distribution of different parts in the same fixed way, different fixed methods and the same fixed parts of different motion states. METHODS:Imaging data of a 34-year-old male patient weighing 68 kg with 33-C1 type fracture of distal femur were selected. CT data were input into Mimics 16.0 for reconstruction. PRO-E software was used to establish minimal y invasive internal fixation system with distal femoral locking plate. Data were introduced into reconstructed models of distal femur fracture in Mimics for grid division. Data were introduced into Ansys products 11.0 to construct finite element model, fix the surface of distal femur, and loaded 340 N on greater trochanter of femur. Stress distribution of each plate, screw hole and screw tail was analyzed in each group. Stress at the same region was compared in flexion and extension movement states. RESULTS AND CONCLUSION:(1) Finite element models of anatomic locking plate for distal femur fracture fixation were successful y established, total y 43 536 units, 41 256 nodes. (2) With the steel segment gradual y down (S1-S5), the stress gradual y increased. A1-A5 with the increase in the number of screws, the stress gradual y increased, but A6 suddenly decreased. (3) According to the cloud atlas of stress, these were wel distributed except A1. From distal end to extremity of screw, the stress of screws increased. Among corresponding segments, significant differences in stress around the nail holes and steel segment stress were detected. Moreover, the steel stress was greater than the stress of corresponding segment of screw hole. (4) Results suggest that using anatomical locking plate and minimal y invasive internal fixation system for distal femur fracture in a variety of fixed modes and moving conditions, the stress of each part is less than the yield strength of the titanium al oy screw, so the fixed system wil not produce instantaneous deformation or fracture.%背景：传统股骨远端固定钢板断钉断板较为常见，临床急待设计解剖贴附好、固定牢靠的内固定系统。 目的：对股骨远端微创内固定系统两种运动状态进行有限元分析，比较同一固定方式下不同部位、不同固定方式及不同运动状态下相同固定部位间的应力分布。 方法：选择1例股骨远端33-C1型骨折患者影像学数据，男性，34岁，68 kg，将CT扫描数据导入Mimics 16.0利用软件重建，利用PRO-E软件建立股骨远端解剖锁定钢板微创内固定系统，并将其导入Mimics中重建好的股骨远端骨折模型中，并网格划分。将文件导入Ansys products 11.0软件中，建立其有限元模型，固定股骨远端表面，于股骨大转子水平断面上表面施加垂直加载340 N载荷，分析各组模型中各钢板、钉孔和螺钉尾部应力分布，并比较前屈后伸运动状态下相同部位的应力。 结果与结论：①成功建立了股骨远端骨折解剖锁定钢板全部置钉固定有限元模型，共有43536个单元，41256个节点；②随着钢板节段逐渐向下(S1-S5)，其应力逐渐增大，A1-A5随着螺钉序数增加，其应力逐渐增大，但A6却突然减小；③由应力分布云图可见，除了A1钉孔螺钉应力分布不均外，其余均分布均匀，由螺钉远端到末端，其应力逐渐增大，相应节段间钉孔与钢板应力比较，钉孔周围应力与钢板节段应力间差异均有显著性意义，且钢板应力大于相应节段钉孔应力；④结果说明，股骨远端骨折解剖锁定钢板微创内固定系统在各种固定方式和运动状态下，各部位应力均小于钛合金螺钉屈服强度，所以固定系统不会产生瞬时变形或断裂。
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