基于非线性材料股骨颈骨折固定方式

Fixation for femoral neck fracture based on nonlinear materials

目的对股骨颈骨折内固定治疗方法中的螺钉固定角度、螺钉数量和螺钉组合方式进行合理选择,以达到最佳的复位稳定性。方法以DICOM数据为基础,建立基于Lindon分型方式的包含不同角度、数量和组合方式的股骨颈骨折内固定三维有限元模型,并依据材料属性参数与CT图片灰度值之间的关系为模型赋予非线性的材料性质,模拟生理载荷条件对模型进行加载。结果临床常见骨折面角度所对应的最佳单钉固定角度为65°和70°;在手术条件允许的情况下,螺钉数量越多,固定效果越好;3钉呈倒三角放置略优于3钉呈正三角放置,3钉呈正三角放置优于2钉,而2钉平放与2钉斜放的优劣取决于骨折面角度。结论骨折面角度对固定的效果有重要影响,股骨颈骨折内固定三维模型的加载仿真过程能够为股骨颈骨折内固定方式的研究提供一种可行途径。

Objective To make a reasonable selection from internal fixation methods for treating femoral neck fracture,namely the fixation angle of a single screw,the number of screws and the combination mode of screws,so as to obtain the optimal stability of fracture reduction.Methods Based on the DICOM data and Lindon mode,a three-dimensional finite element model of femoral neck fracture fixation was built including different angles,numbers and combination modes of the screws.The model was attributed to nonlinear material properties based on the relationship between the property parameters of bone materials and the gray value of CT images,and loaded under the simulation of physiological loads.Results Corresponding to different angles of the fracture surface,the optimal fixation angle of the single screw was 65°and 70°in clinic.The more the number of screws,the better the effect of fixation,when the surgical condition was permitted.The inverted triangle placement was better than the triangle placement in case of three-screw fixation,while the triangle placement was superior to two-screw fixation,but the decision on the placement of two-screw fixation in flat form or diagonal form depended on the angle of the fracture surface.Conclusions Different angles of the fracture surface have significant impacts on the effect of fixation,and the loading simulation process on the three-dimensional model can provide a feasible way to the study of the fixation for the femoral neck fracture.