两种螺钉固定方式对于内收型股骨颈骨折的有限元分析

发布时间：2018-01-24 11:19

本文关键词： 股骨颈骨折有限元分析空心钉 F-技术生物力学　出处：《山西医科大学》2017年硕士论文　论文类型：学位论文

【摘要】：目的:1、通过Mimics等软件对CT数据进行有限元处理,建立股骨颈骨折模型;2、获取各个模型使用不同空心钉排布(三枚骨松质拉力螺钉平行、空心钉“F”技术)固定时的应力、应变、位移云图进行对比分析,评估指导临床治疗;方法:通过使用薄层CT对志愿者健侧下肢进行扫描,得到的数据以.dicom格式保存.利用Mimics软件读取.dicom文件完成正常股骨上段的重建。重建后模拟股骨颈骨折,保存为.inp格式文件。使用Hypermesh软件股骨颈骨折模型网格化划分后,在Mimics软件中对股骨颈骨折模型按照公式进行材料属性的赋予。在UG4.0软件建立骨松质拉力螺钉模型(螺钉外径为6.5mm,内径为2.5mm,有螺纹部分长度为20mm,螺距为0.2mm,螺钉总长度长度为90mm)并建立两组内固定模型将其存为.stl格式。通过Mimics中对骨折及内固定模型进行处理,模拟出带螺孔的骨折模型后,在UG中对螺钉网格划分并保存为.inp格式。UG中完成对二者的装配,在Ansys中完成对骨折内固定复合体设置边界条件,施加载荷,定义接触,最后进行有限元分析计算。结果:1.较为准确的建立了股骨颈骨折使用两种内固定术后的有限元模型。2.应力分布位置跟其峰值:正常股骨上段最大应力为18.968MBa,倒品排布组最大值为65.954MPa,F技术固定组最大应力为39.532MPa;倒品排布组螺钉最大应力为39.532MPa,F-技术组螺钉最大应力为58.252MPa。倒品固定组远端骨折块最大应力为65.594MPa,近端骨折块最大应力18.349MPa.F技术固定组远端骨折块最大应力为36.591MPa,近端骨折块最大应力16.931MPa.3.应变分布位置跟其峰值:正常股骨模型中皮质骨最大应变为0.022734、松质骨为0.011753;倒品字排布组的皮质骨最大应变为0.0044786、松质骨为0.0098978;F-技术组皮质骨最大应变为0.0021794、松质骨为0.0025088。4.股骨位移分布位置跟其峰值:正常股骨上段模型最大位移为0.4488mm,倒品字排布模型的的最大位移为0.41514mm,F-技术组模型最大位移为0.4mm,结论:1.固定后股骨位移均为一个数量级,F技术固定组可明显减少松质骨应力应变,更好的将应力应变更均匀传导骨质。2.F技术固定后螺钉应力较倒品固定组较高,对螺钉要求更高,术后发生断钉风险较倒品固定较高。3.F技术固定相对而言更适合骨质情况较差患者。
[Abstract]:Objective to establish the femoral neck fracture model by using Mimics and other software to process CT data by finite element method. 2. The stress, strain and displacement of each model were compared and analyzed with different hollow screws (three cancellous lag screws parallel, hollow nail "F" technique), and the clinical treatment was evaluated. Methods: the healthy lower limbs of volunteers were scanned by thin slice CT. The obtained data was saved in the format of .dicom. The normal upper femur was reconstructed by reading the .dicom file with Mimics software. The femoral neck fracture was simulated after reconstruction. Save the file in .inp format. Use Hypermesh software to mesh the femoral neck fracture model. The model of femoral neck fracture was endowed with material properties according to the formula in Mimics software. The model of cancellous screw was established in UG4.0 software (external diameter of screw was 6.5 mm). The inner diameter is 2.5mm, the length of the threaded part is 20mm and the pitch is 0.2mm. The total length of screw was 90 mm) and two groups of internal fixation models were set up to store them as. STL format. The fracture and internal fixation model were treated by Mimics, and the fracture model with screw holes was simulated. The screw mesh was divided in UG and saved to .inp format. UG was used to complete the assembly of the two, and the boundary condition was set up in Ansys, the load was applied and the contact was defined. Finally, finite element analysis and calculation were carried out. Results 1. The finite element model of femoral neck fracture after two kinds of internal fixation was established more accurately. 2. The stress distribution position and its peak value:. The maximum stress of normal upper femur was 18.968 MBa. The maximum stress was 39.532MPa in the technique fixation group (65.954 MPA / F). The maximum stress of screw in reverse packing group was 39.532MPaF- the maximum stress of screw in technical group was 58.252MPa. the maximum stress of distal fracture block in reverse fixation group was 65.594MPa. The maximum stress of proximal fracture was 18.349MPa.F technique. The maximum stress of distal fracture was 36.591MPa. The maximum stress of proximal fracture was 16.931MPa.3.The maximum strain of cortical bone and cancellous bone was 0.022734 and 0.011753 respectively. The maximum strain of cortical bone and cancellous bone were 0.0044786 and 0.0098978 respectively. The maximum strain of cortical bone in F- technique group was 0.0021794. The position of femoral displacement distribution and its peak value were 0.0025088.44.The maximum displacement of normal proximal femur model was 0.4488mm. The maximum displacement of the reverse typesetting model was 0.41514mm / F-, the maximum displacement of the model was 0.4mm.Conclusion: 1.The femoral displacement after fixation was of one order of magnitude. The stress and strain of cancellous bone were significantly reduced in F group, and the stress of screws after fixation was higher than that of reverse fixation group, and the requirement of screws was higher. The risk of post-operative nail breakage was higher than that of reverse fixation. 3. F technique was relatively more suitable for patients with poor bone condition.
【学位授予单位】：山西医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R687.3

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