全膝关节置换术对胫骨近端骨重建的影响

发布时间：2018-12-16 13:04

【摘要】：全膝关节置换手术是减轻关节炎患者病痛最有效的手段之一，但术后特别容易出现假体下沉、松动等一系列不良症状，导致假体的使用寿命缩短。其中，假体的应力遮挡效应导致的骨密度降低是诱发术后症状的重要原因。骨重建模拟可以实现对胫骨密度分布的数值模拟，还可以预测全膝关节置换术后骨密度变化及胫骨重建情况，对研究临床假体失效机理和防治置换术后不良症状的出现具有重要作用。目前，国内外采用骨功能适应性理论对胫骨近端骨重建的模拟研究，大多是以平面模拟为主，三维结构模拟很少。本文采用三维胫骨模型，能够更为全面细致的研究不同材料的假体对胫骨重建的影响。本文的主要内容为：首先采用CATIA软件建立胫骨近端三维几何模型，以及短柄假体三维模型，然后将实体模型导入ANSYS软件中，利用智能网格划分法划分四面体网格。采用ANSYS中的APDL语言编写有限元计算程序，，结合MATLAB中编写骨重建程序，通过MATLAB调用ANSYS实现了对胫骨近端骨重建过程的模拟。然后模拟人工膝关节置换术后胫骨的骨重建过程，建立了四个胫骨-假体有限元模型，四个模型的假体结构相同，但是材料不同（包括两种功能梯度材料、传统的钛合金材料和作为对照的理想骨材料），以此分析四种不同的假体材料对胫骨骨重建的影响。分析结果表明，采用功能梯度材料假体的模型相对于采用钛合金材料假体的模型，其胫骨承担的Von Mises应力更高，在一定程度上减轻了假体的应力遮挡效应；同时采用功能梯度材料假体的模型其胫骨与假体交界处切应力分布更为均匀，胫骨与假体间的应力能够更加有效地传递。但是，这四种材料假体骨密度分布的模拟结果差异并不明显，说明短柄膝关节假体对于骨重建的影响是很有限的。通过本文的研究，能够为膝关节假体材料和结构的改善提供一定的理论依据，同时是深入研究膝关节假体与骨之间相互作用的基础。
[Abstract]:Total knee arthroplasty is one of the most effective methods to alleviate the pain in patients with arthritis, but it is easy to appear a series of adverse symptoms such as prosthesis sinking and loosening after operation, which results in the shortening of the service life of the prosthesis. The decrease of bone mineral density caused by stress occlusion of prosthesis is an important cause of postoperative symptoms. Bone reconstruction simulation can simulate the density distribution of tibia and predict the changes of bone mineral density and tibial reconstruction after total knee arthroplasty. It plays an important role in studying the mechanism of clinical prosthesis failure and preventing the occurrence of adverse symptoms after replacement. At present, the theory of bone functional adaptability is used to simulate the proximal tibia bone reconstruction, most of which are plane simulation, and the three-dimensional structure simulation is seldom. In this paper, a three-dimensional tibial model is used to study the effects of different materials on tibial reconstruction. The main contents of this paper are as follows: firstly, the three-dimensional geometric model of proximal tibia and the three-dimensional model of short handle prosthesis are established by using CATIA software, then the entity model is imported into ANSYS software, and the tetrahedron mesh is divided by intelligent mesh division method. The process of proximal tibial bone reconstruction was simulated by MATLAB calling ANSYS with APDL language in ANSYS and bone reconstruction program in MATLAB. Four finite element models of tibial prosthesis were established. The four models had the same structure but different materials (including two kinds of functionally gradient materials). Traditional titanium alloy materials and ideal bone materials as control were used to analyze the effects of four different prosthetic materials on tibial bone reconstruction. The results show that the tibia bearing Von Mises stress of the model with functionally graded material is higher than that with titanium alloy, and the stress shielding effect of the prosthesis is alleviated to a certain extent. At the same time, the shear stress distribution at the tibia and the prosthesis is more uniform, and the stress between the tibia and the prosthesis can be transferred more effectively by using the model of functionally gradient material prosthesis. However, there is no significant difference in bone mineral density distribution between the four prostheses, indicating that the effects of short handle knee prosthesis on bone reconstruction are very limited. The research in this paper can provide a theoretical basis for the improvement of the material and structure of the knee joint prosthesis, and it is also the basis for the in-depth study of the interaction between the knee joint prosthesis and the bone.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R687.4

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