髋臼骨折术后股骨头内移对臼顶负重区应力影响的有限元分析

发布时间：2018-01-21 22:00

本文关键词： 髋臼骨折股骨头内移创伤性关节炎有限元分析接触应力　出处：《天津医科大学》2015年硕士论文　论文类型：学位论文

【摘要】：目的(1)定义髋臼骨折术后股骨头内移指数的概念及测量方法。(2)通过对髋臼内侧壁截骨建立不同股骨头内移位置下的髋关节有限元模型。(3)应用有限元分析方法研究髋臼骨折术后股骨头内移对臼顶负重区接触应力大小及分布的影响,为临床医师研究髋臼骨折术后患者髋关节生物力学变化提供参考依据,从而预测该变化与髋关节创伤性骨关节炎之间的相关性。方法(1)对髋臼骨折术后患者进行随访并收集病例资料,筛选出存在不同程度股骨头内移的患者8例,均行骨盆正位X线片及骨盆CT平扫检查,将所有患者骨盆CT平扫数据以DICOM格式导出存入光盘,并在Mimics软件中重建骨盆三维模型。分别在骨盆平片和三维模型上测量股骨头内移指数,对所得数据进行统计学分析,比较两组数据之间的差异有无统计学意义。(2)选择一健康成年男性(33岁,70kg),提取骨盆CT扫描DICOM数据,通过Mimics17.0软件构建该志愿者左侧髋关节三维仿真模型,使用该软件手术模拟版块中截骨工具对髋臼内侧壁进行截骨,并使股骨头与所截内侧壁骨块同步内移,以2mm为移动单位对不同股骨头内移位置下髋关节模型进行分组,包括正常髋关节共7组。对模型进行一系列处理,如软骨再造、网格化、赋值等操作后,将模型导入有限元分析软件ANSYS中进行相关调整,设置髋关节面间接触属性后,建立不同股骨头内移位置下髋关节间力学分析的有限元模型。(3)对所有模型施加相同的载荷并设定边界条件,模拟单足站立位髋臼顶负重区应力分布情况,通过比较相同限制条件下股骨头内移后髋关节间接触应力的大小及分布变化情况,为临床上分析股骨头内移与髋臼骨折术后创伤性关节炎之间的相关性提供理论依据。结果(1)应用Mimics三维重建软件基于多层螺旋CT和DICOM技术,建立骨盆及单侧髋关节三维仿真模型,其几何外形与真实解剖结构相符,可用于进一步研究。(2)对8例髋臼骨折术后患者骨盆正位X线片及三维重建模型的股骨头内移指数分别进行测量,将两组数据进行配对设计资料的t检验,t值为2.522,P=0.046,P值小于0.05,两组数据有统计学差异。(3)可利用Mimics及其配套3-matic软件对模型进行软骨再造、面网格、体网格化等操作,形成左侧股骨节点117402个,四面体单元83714个;髋骨节点218557个,四面体单元数为152197个,根据灰度值对软骨之外的模型进行赋值并存储为可导入有限元分析软件的格式。(4)在ANSYS有限元分析软件中计算七组髋关节模型臼顶负重区应力分布,得到相应的受力云图;单腿站立时正常髋关节臼顶负重区应力峰值为3.01MPa,随着股骨头内移,髋关节臼顶负重区与股骨头接触区域出现应力集中,且最高峰值可达16.47MPa,尤其当股骨头内移大于6mm时应力峰值超过正常承受范围。结论:(1)标准骨盆正位X线片上股骨头内移指数的测量有一定提示意义,但由于受检者体位、骨折等因素影响很难获得绝对标准骨盆正位X片,而骨盆三维重建模型可任意调整骨盆位置,测得结果可靠性更高。(2)基于骨盆CT数据,通过三维重建及有限元分析软件,准确构建出带有关节软骨的正常髋关节和不同股骨头内移位置下的髋关节三维有限元力学分析模型。(3)股骨头内移后髋关节力学环境发生改变,随着股骨头内移臼顶负重区应力集中区增大,应力峰值增高,这可能是促进髋臼骨折术后创伤性关节炎发生的因素之一。(4)髋臼骨折时,在解剖复位髋臼顶负重区的前提下,应尽量复位并坚强固定内侧壁骨块,对髋臼骨折术后股骨头位置的恢复有一定作用。
[Abstract]:Objective (1) defines the concepts and measurement methods of acetabular fractures after femoral head displacement index. (2) through the establishment of finite element model of different hip femoral head shift location on the medial wall of the acetabulum osteotomy. (3) the contact stress distribution and size of the femoral head shift on acetabular roof weight-bearing area of operation using the finite element analysis method of acetabular fracture, and to provide reference for clinical research in patients with hip biomechanics changes after operative treatment of acetabular fractures, and predict the correlation between the changes and hip traumatic osteoarthritis. Methods (1) of the acetabular fracture patients were followed up and collected clinical data, were screened for the presence of 8 patients with different degree of femoral head displacement patients underwent pelvic radiograph and pelvic CT scan examination, all patients with pelvic CT scan data in DICOM format and stored in CD, and reconstruction of pelvic 3D model in Mimics software Type respectively. The femoral head shift index measurement in pelvic plain films and three-dimensional model, for statistical data analysis, compare the differences between the two groups of data has no statistical significance. (2) choose a healthy adult male (33, 70kg), extraction of pelvic CT scan DICOM data, through the Mimics17.0 software to build the the volunteers left hip 3D simulation model, using the software simulation of operation section osteotomy of acetabular osteotomy tool and the medial wall of the femoral head and the medial wall of the bone in the section of synchronous shift, 2mm group shift hip femoral head position model under different mobile units, including the normal hip joint a total of 7 groups. A series of models, such as cartilage reconstruction, mesh, assignment, model into finite element analysis software ANSYS for related adjustment, setting of hip joint surface contact between properties, establish different femoral Displacement finite element analysis of hip mechanics between the position of the head model. (3) applied the same load on all models and set the boundary conditions, simulation of single leg stance the acetabular dome region of stress distribution, through the comparison of the same limits change the size and distribution of conditions in the femoral head after hip joint contact shift the stress, displacement and provide a theoretical basis and the correlation between acetabular fractures after traumatic arthritis in the femoral head for clinical analysis. Results (1) the application of Mimics software of three-dimensional reconstruction of multi-slice spiral CT and DICOM technology based on the establishment of pelvis and unilateral hip 3D simulation model, the geometric shape and the real anatomy can match for the further study. (2) of 8 cases of acetabular fracture patients with postoperative pelvic radiograph and three-dimensional reconstruction model of femoral head displacement index were measured, and the data of the two groups by paired t test Check the value of T was 2.522, P=0.046, P value is less than 0.05, the data of the two groups had significant difference. (3) the model of cartilage reengineering, using Mimics and 3-matic software supporting surface mesh, mesh and other operations, the formation of the left femur of 117402 nodes, 83714 nodes tetrahedron; hip 218557, tetrahedron unit number 152197, according to the assignment and storage for the finite element analysis software format of cartilage outside the gray value. The model (4) in the ANSYS finite element analysis software to calculate the seven groups of hip acetabular dome model stress distribution, get the stress contours corresponding to normal single leg standing; hip acetabular dome region stress peak is 3.01MPa, with the shift in the femoral head, hip acetabular dome region of femoral head and the contact area of stress concentration, and the highest peak of up to 16.47MPa, especially when more than 6mm peak stress than in the femoral head shift Under normal range. Conclusion: (1) the standard pelvic radiograph on femoral head displacement measurement index has a certain significance, but because of the subject position, influence factors such as fracture is difficult to obtain the absolute standard anteroposterior pelvic X, and pelvic reconstruction of 3D model can be arbitrary pelvic bone position adjustment, measured the results are more reliable. (2) based on the CT data through the pelvis, 3D reconstruction and finite element analysis software, accurate analysis to construct the three-dimensional finite element model of hip mechanics with normal articular cartilage of the hip and femoral head in different positions. The shift (3) in the femoral head after the shift hip mechanics environment changes with the shift in the femoral head, joint stress concentration zone increases bearing area of top, the peak stress increased, which may be one of the factors for the occurrence of traumatic arthritis after acetabular fracture surgery to promote. (4) acetabular fractures, based on anatomical reduction of acetabular dome region under the, It is necessary to restore and firmly fix the bone mass of the medial wall as far as possible. It has some effect on the recovery of the position of the femoral head after the operation of the acetabular fracture.

【学位授予单位】：天津医科大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R687.3

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