运动力学对线的人工膝关节有限元建模和生物力学研究

发布时间：2018-04-29 18:53

本文选题：膝关节 + 假体　；参考：《第二军医大学》2017年博士论文

【摘要】：研究背景膝关节是人体下肢的枢纽关节,其复杂组织解剖结构、运动模式和所处的力学环境及其功能要求使其易受创伤和骨性关节炎等疾病累及,伤病发生率居各关节之首。人工全膝关节置换术(Total Knee Arthroplasty,TKA或Total Knee Replacement,TKR)是采用手术的方法将病损的膝关节负重面替换为人工关节材料,从而消除膝关节疼痛、恢复下肢生理力线、改善膝关节活动功能。TKA是骨科最成功的经典手术之一,它使过去只能依赖药物缓解疼痛无法长距离行走,甚至只能截肢的患者恢复了行走功能,大大改善了患者的生活质量。TKA不仅仅是骨的手术,更是软组织的手术,下肢力线精确重建、假体位置正确安置是影响术后关节功能和假体使用寿命的重要因素,对评估手术成败和术后疗效有重要的参考价值。为了提高TKA术中下肢力线重建的准确性,大量的医疗卫生资源和研究精力被投入到术中计算机辅助导航技术和个体化手术工具(patient specific instrument,PSI)的研究中。人工全膝关节置换领域传统的观点认为TKA术后患者下肢力线应重建至与中立位力线偏差小于3°的位置。近年来有很多术后随访研究发现TKA术后重建的下肢力线无论是否与中立位力线偏差在3°以内,患者术后的人工关节假体生存率并无显著差异。这些研究结果让研究者们开始思考TKA对线标准是否存在不足,Howell等一些学者更进一步提出了运动力学对线TKA(Kinematical Alignment TKA,KA-TKA)概念,即TKA应以患者膝关节正常状态的或病损前状态的运动轴为对线、定位参考进行截骨、假体安置,从而在术后使人工膝关节尽可能的模拟人体膝关节正常的生物力学状态。目前KA-TKA成为关注的热点是因为经典的MA-TKA术后出现了较高的不满意率。从理论上说,相对于MA-TKA的机械力学对线方式,KA-TKA的运动力学对线方式能最大程度的恢复患者的膝关节生物力学和运动力学环境,从而获得更好的手术效果和临床疗效,但目前相关临床和基础研究还远远不足以充分的证明这一观点,KA-TKA是否更具优势,尚需进一步研究验证。第一部分:人体膝关节和人工膝关节真几何模型和有限元模型的建立目的:建立人体膝关节和TKA假体仿真几何模型和有限元模型,为进行膝关节和TKA术后的生物力学分析建立基础。方法:选择一名健康成年人志愿者,使用CT进行左侧下肢全长扫描,MRI进行膝关节扫描,获取医学影像数据,利用Mimics15.0、UG NX 7.0、ABAQUS 6.8等图像处理分析软件和有限元分析软件,重建了人体膝关节仿真几何模型,在此几何模型基础上,运用有限元软件构建膝关节的有限元模型。利用逆向工程技术和Geomagic Studio 9.0软件将施乐辉公司(SmithNephew Inc.)Genesis II后稳定型人工全膝关节假体的外形扫描数据重建为几何模型,将其和膝关节模型进行装配,获得人工全膝关节置换术后膝关节几何模型和有限元模型。结果:建立了适用于进行膝关节和人工全膝关节置换术后生物力学分析的解剖型仿真几何模型和有限元模型。结论:本研究利用CT、MRI影像数据和逆向工程技术所建立的人体膝关节和人工膝关节假体仿真几何模型和有限元模型,与人体膝关节解剖结构一致,可逼真的重现膝关节的真实结构,用于TKA手术仿真、模拟并进行生物力学分析。第二部分:运动力学与机械力学对线的人工膝关节生物力学分析目的:有限元分析比较运动力学对线和机械力学对线的人工全膝关节置换术术后生物力学特性,重点探讨两种对线方式下人工关节接触面的应力和应变情况。方法:随机选择12名健康成年人志愿者,根据第一部分的建模方法,获取志愿者左侧膝关节仿真几何模型和有限元模型,选择合适大小的人工全膝关节假体,按运动力学对线方式和机械力学对线方式分别进行虚拟截骨、假体安装,通过有限元分析软件仿真单足站立情形施加载荷,观察人工关节假体接触面的最大应力和最大应变情况。结果:按机械力学对线(MA)方式放置安装假体后,股骨假体接触表面最大应力为38.25±2.66MPa,,按运动力学对线(KA)方式安置假体后,最大应力减小为30.37±2.76MPa,差异具有统计学意义,P0.05。在超高分子聚乙烯垫片表面,MA方式时最大应力为12.07±1.67MPa,KA方式时最大应力减小为8.14±2.49MPa,差异具有统计学意义,P0.05。在MA方式下股骨假体接触表面最大应变为1.51x10~(-4)±1.09x10-5mm,KA方式时最大应变为8.18x10-5±1.05x10-5mm,小于MA方式时的形变,差异具有统计学意义,P0.05。在超高分子聚乙烯垫片表面,MA方式时最大应变为3.43x x10~(-3)±5.12x10~(-4)mm,KA方式时应变减小,为2.10 x10~(-3)±3.86x10~(-4)mm,差异具有统计学意义,P0.05。结论:与传统机械力学对线方式相比,按运动力学对线方式进行人工全膝关节置换术可降低股骨假体和胫骨聚乙烯衬垫表面的最大应力和最大应变,使人工关节接触面压力分布更均匀,从而减少关节接触面的磨损,延长假体寿命。
[Abstract]:The knee joint is the hinge joint of the lower limbs of the human body. The complex anatomical structure of the knee, the mode of motion, the mechanical environment and its function requirements make it susceptible to the diseases such as trauma and osteoarthritis, and the incidence of injury is the first. Total knee arthroplasty (Total Knee Arthroplasty, TKA or Total Knee Replacemen) T, TKR) is an operation method to replace the damaged surface of the knee joint as artificial joint material, so as to eliminate the pain of the knee joint, restore the physiological force line of the lower limbs, and improve the function of the knee joint,.TKA is one of the most successful classic operations in the Department of orthopedics. It can only rely on drugs to relieve pain and can not walk long distance, or even amputate only. The patients recovered the walking function, which greatly improved the patient's quality of life.TKA not only the bone operation, but also the soft tissue operation, the accurate reconstruction of the lower limb force line, the correct placement of the prosthesis position is an important factor affecting the postoperative joint function and the life of the prosthesis. It has important reference value for evaluating the success and failure of hand operation and the postoperative effect. To improve the accuracy of the reconstruction of the lower limb force line in TKA, a large number of medical and health resources and research energy have been put into the study of the patient specific instrument (PSI). The traditional point of view in the field of artificial total knee arthroplasty is that the lower limb force line of the patients after TKA should be rebuilt to the middle of the operation. In recent years, many postoperative follow-up studies have found that there is no significant difference in the survival rate of the artificial joint prosthesis after the TKA reconstruction of the lower limb force line within 3 degrees, whether or not the deviation of the force line between the TKA and the neutral force line is within 3 degrees. These results allow the researchers to begin to think about the deficiency of the TKA line standard, H Owell and other scholars have further proposed the concept of motion mechanics to line TKA (Kinematical Alignment TKA, KA-TKA), that is, TKA should be the alignment of the normal state of the knee joint or the motion axis of the condition before the disease, locating the reference for osteotomy and prosthesis placement, so as to make the artificial knee joint as possible as possible to simulate the normal knee joint of the human body after the operation. Biomechanical state. At present, KA-TKA has become the focus of attention because of the high dissatisfaction rate after the classical MA-TKA. In theory, compared with the mechanical mechanics of MA-TKA, the motion mechanics of KA-TKA can maximize the recovery of the mechanical and mechanical environment of the knee joint of the patient. The effect of operation and clinical efficacy, but the current related clinical and basic research is still far from sufficient proof of this view, whether KA-TKA is more advantageous and still needs further research. Part 1: the establishment of the true geometric model and the finite element model of the human knee joint and the artificial knee joint: the establishment of the human knee joint and the TKA prosthesis. The real geometric model and the finite element model set up the basis for the biomechanical analysis of the knee joint and TKA. Methods: a healthy adult volunteer was selected, CT was used to scan the left lower limb full length scan, the MRI was scanned for the knee joint, the medical image data were obtained, and the image processing analysis software, such as Mimics15.0, UG NX 7, ABAQUS 6.8 and so on, was used. The finite element analysis software is used to reconstruct the simulation geometric model of the human knee joint. On the basis of this geometric model, the finite element model of the knee joint is constructed with the finite element software. The shape scanning of the stable artificial total knee prosthesis after SmithNephew Inc. Genesis II is used by reverse engineering and Geomagic Studio 9 software. The geometric model and the knee joint model were assembled to obtain the geometric model and finite element model of the knee joint after total knee arthroplasty. Results: an anatomical model and finite element model for biomechanical analysis of the knee and total knee replacement were established. Conclusion: This study The simulation geometric model and finite element model of the human knee joint and artificial knee joint prosthesis established by CT, MRI image data and reverse engineering technology are consistent with the anatomical structure of the human knee joint. It can realistically reproduce the true structure of the knee joint. It is used for the simulation of TKA operation, simulation and biomechanical analysis. The second part: the motion mechanics and the biomechanics analysis. Biomechanical analysis of the artificial knee joint with mechanical mechanics. The finite element analysis is used to compare the biomechanical characteristics of the artificial total knee replacement after the line and mechanic mechanics to the line by finite element analysis. The stress and strain situation of the contact surface of the artificial joints under two lines are discussed. Method: 12 healthy adult chronicles are selected randomly. According to the modeling method of the first part, the volunteers can obtain the simulated geometric model and finite element model of the left knee joint of the volunteers, select the suitable artificial total knee prosthesis, carry out the virtual osteotomy, the installation of the prosthesis on the line mode and the mechanical mechanics according to the motion mechanics, and simulate the standing situation by the finite element analysis software. The maximum stress and maximum strain on the contact surface of artificial joint prosthesis were observed. Results: the maximum stress of the contact surface of the femoral prosthesis was 38.25 + 2.66MPa, and the maximum stress was reduced to 30.37 + 2.76MPa according to the mechanical mechanical pair of prosthesis (MA), and the difference was statistically significant. The maximum stress of P0.05. on the surface of ultra-high polymer polyethylene gasket is 12.07 + 1.67MPa, and the maximum stress decreases at 8.14 + 2.49MPa in KA mode, and the difference is statistically significant. The maximum strain of P0.05. in MA mode is 1.51x10~ (-4) + 1.09x10-5mm, and the maximum strain of KA mode is 8.18x10-5 +. Mm, the deformation of less than MA is statistically significant. The maximum strain of P0.05. on the surface of ultra-high polymer polyethylene gasket is 3.43x x10~ (-3) + 5.12x10~ (-4) mm and KA mode. The difference has statistical significance. The difference has statistical significance. Artificial total knee replacement with motion mechanics can reduce the maximum stress and maximum strain on the surface of the femoral prosthesis and tibial polyethylene pad, and make the pressure distribution more uniform on the contact surface of the artificial joints, thus reducing the wear of the joint contact surface and prolonging the life of the prosthesis.

【学位授予单位】：第二军医大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：R687.4

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