【作者】 赖震；

【导师】 孙俊英；

【作者基本信息】 苏州大学 ， 骨外科学， 2008， 博士

【摘要】 第一部分成人髋臼发育不良三维有限元模型构建及其力学分析目的研究正常成人髋关节和髋臼发育不良成人髋关节三维有限元模型的构建,并通过有限元分析探讨其关节应力分布的变化。方法根据成人正常髋关节和不同类型髋臼发育不良髋关节薄层CT扫描数据,运用Mimics10.0软件进行三维重建,利用有限元分析软件ANSYS10.0构建成人正常髋关节和不同类型髋臼发育不良髋关节三维有限元模型。模拟并加载关节负荷,分析计算缓慢行走单足着地状态下关节软骨和软骨下骨的Von Mises应力分布及传递。结果所构建髋关节三维有限元模型能逼真反映成人正常髋关节和不同类型髋臼发育不良患者髋关节的真实几何形态及其生物力学特点。在正常髋关节、发育不良型、低位脱位型髋关节中,接触应力均发生在股骨头软骨最上部及与其相对应的髋臼软骨顶穹部。在髋臼发育不良型和低位脱位型髋关节中,在髋臼软骨的后上缘区域存在较高的接触应力区。在正常髋关节中,股骨头软骨的上方负重区及髋臼软骨的顶穹部峰值Von Mises应力分别为2.02MPa和2.37MPa。在发育不良型髋关节中,股骨头软骨及髋臼软骨峰值Von Mises应力分别为4.23MPa和5.43MPa;在低位脱位型髋关节中,股骨头软骨及髋臼软骨峰值Von Mises应力分别为8.45MPa和10.32MPa。高位脱位型髋关节中,股骨头软骨峰值Von Mises应力为8.67MPa,而由于真臼软骨失去股骨头的接触,故峰值Von Mises应力则反而下降为0.59MPa。在正常髋关节、发育不良型、低位脱位型髋关节中髋臼软骨下骨的应力分布与关节表面的接触应力分布相似。即应力主要集中在髋臼软骨下骨的顶穹部,并以放射状分布向周边逐渐减弱。4种髋关节模型股骨侧应力传递是从股骨头经股骨颈到近段股骨的内上侧,股骨颈内侧小转子上方股骨距区存在较高的压应力分布区。正常髋关节、发育不良型、低位脱位型髋关节中,股骨头软骨下骨应力集中区均发生在股骨头最上四分之一象限,接近于矢状轴的尖部;高位脱位型髋关节中,股骨头软骨下骨应力集中区则位于股骨头前内四分之一象限。在正常髋关节中,股骨头和髋臼软骨下骨峰值Von Mises应力分别为8.65MPa和2.52MPa;在发育不良型髋关节中,股骨头和髋臼软骨下骨峰值Von Mises应力分别为8.92MPa和2.73MPa;在低位脱位型髋关节中,股骨头和髋臼软骨下骨峰值Von Mises应力分别为10.65MPa和4.02MPa;高位脱位型髋关节中,股骨头软骨下骨和假臼峰值Von Mises应力分别为8.17MPa和8.59 MPa。结论通过薄层CT数据构建的成人正常髋关节和不同类型髋臼发育不良髋关节三维有限元模型具有较高的仿真度,该模型能够模拟分析髋关节应力分布,为研究成人髋臼发育不良的生物力学行为和进行相关力学基础研究提供了精确模型。第二部分髋中心内移全髋置换的三维有限元分析目的建立以不同髋中心内移全髋置换术后三维有限元模型,分析研究髋中心内移对假体Von Mises应力分布的影响,为临床应用髋中心内移技术提供理论依据。方法根据正常成人薄层CT扫描数据重建髋臼模型,按假体的各项参数建立髋臼假体模型,运用布尔运算模拟临床手术要求进行打磨髋臼,植入假体。建立不同髋中心植入髋臼假体的全髋关节置换术后三维有限元模型,模拟并加载关节负荷,分析研究聚乙烯内衬和股骨假体头颈结合部的Von Mises应力分布。结果在缓慢行走单足着地状态载荷下,髋臼中心内移影响聚乙烯内衬和假体头颈结合部的应力分布,在聚乙烯应力主要集中在内衬的内面,而背面无明显应力集中。正常髋臼中心放置时,聚乙烯内衬峰值Von Mises应力为4.24MPa,假体头颈结合部峰值Von Mises应力为17.02MPa;当髋中心内移后假体内壁距离K?hler线3mm时,聚乙烯内衬峰值Von Mises应力为4.35MPa,假体头颈结合部峰值Von Mises应力为17.78 MPa,分别较正常髋中心时增大2.59%和4.47%;髋中心内移后假体内壁接触K?hler线时,聚乙烯内衬峰值Von Mises应力为4.70MPa,假体头颈结合部峰值Von Mises应力为18.93MPa,分别较正常髋中心时增大10.85%和11.22%;髋中心内移后假体内壁超过K?hler线3mm时,聚乙烯内衬峰值Von Mises应力为4.97MPa,假体头颈结合部峰值Von Mises应力为20.50MPa,分别较正常髋中心时增大17.22%和20.45%;髋中心内移后假体内壁超过K?hler线6mm时,聚乙烯内衬峰值Von Mises应力为5.67MPa,假体头颈结合部峰值Von Mises应力为25.36 MPa,分别较正常髋中心时增大33.73%和49.00%。结论聚己烯内衬和假体头颈结合部峰值Von Mises应力随髋中心内移距离的增加而增大,当假体内壁超过K?hler线后,峰值Von Mises应力明显增大。第三部分不同前倾角股骨假体植入的三维有限元分析目的建立以不同前倾角植入股骨假体的全髋关节置换术后三维有限元模型,分析研究不同前倾角植入股骨假体后,股骨和假体应力分布以及假体初始微动,为临床提供理论依据。方法根据正常成人薄层CT扫描数据重建股骨模型,按股骨假体的各项参数建立股骨假体模型,模拟临床手术要求进行截骨,以0°、15°和30°前倾角植入股骨假体,建立全髋关节置换术后股骨侧三维有限元模型,模拟并加载关节负荷,分析不同前倾角假体植入后股骨及假体Von Mises应力分布,假体界面主应力、剪切力分布和假体初始微动的改变。结果(1)假体植入后,股骨所承受的负荷主要通过假体传向股骨远段,股骨近段大粗隆区域和股骨距区域应力减少,在假体柄端区的骨质表现出高应力,股骨干中远段出现应力集中现象。股骨假体以0°和30°前倾角植入较15°前倾角植入,股骨近段所承受的负荷减小,而在假体柄端远侧区域出现应力集中现象明显。15°前倾角植入时高应力的位置为股骨的内外侧,而0°和30°前倾角植入时高应力的位置逐渐向前后侧转移,改变了正常股骨在承受假体载荷后所表现的内侧的压应变和外侧的张应变的受力模式。(2)股骨假体以0°和30°前倾角植入较15°前倾角植入,股骨假体各部分的Von Mises应力增大,在假体颈部出现应力集中现象严重。不同前倾角股骨假体植入后,股骨假体界面应力发生变化,0°和30°前倾角植入时股骨假体界面主应力和剪切力分别比15°前倾角植入时增大。(3)在股骨近段,假体周围的骨质应力维持于低水平,而假体承受了绝大部分的应力,形成了应力遮挡。股骨假体以0°和30°前倾角植入时,在截骨平面的股骨大粗隆和股骨距区域承受的载荷较15°前倾角植入时承受的载荷减小;在截骨平面的假体承受的载荷较15°前倾角植入时假体承受的载荷增加。在股骨外侧大粗隆区域和股骨距区域应力减少,产生严重的应力遮挡,以15°前倾角植入时应力遮挡最小。(4)股骨假体以0°和30°前倾角植入时,股骨假体各部分的初始微动较15°前倾角植入时增大。结论全髋置换术后股骨近段产生应力遮挡,在假体柄端远侧区域出现应力集中现象。股骨假体以15°前倾角植入假体将获得最佳的近段匹配,使股骨近段获得更多的载荷,有效降低股骨及假体应力集中、应力遮挡、假体界面应力和假体初始微动,有利于骨长入及远期稳定。更多还原

【Abstract】 Part 1 Three-dimensional Finite Element Model of the Adults Developmental Dysplasia of the Hip:construction and stress analysisObjective To construct three-dimensional (3D) finite element models of the normal hip and adults developmental dysplasia of the hip and analyze stress distributions in the hips of different types.Methods 3D models of the normal human hip and different type adults developmental dysplasia of the hips were constructed from lamellar CT images with Mimics software, and then converted to 3D finite element units by Ansys10.0 software. Mechanical parameters were used to construct 3D finite element hip models. With the application of hip joint loading, stress changes of hips were measured. The models were tested and their stress distributions were compared.Results The constructed 3D finite element hip models clearly reflected the rea1 hip anatomy and biomechanica1 behavior of patients.The magnitudes of peak contact pressure differed between apposed articular surfaces of different type hips. It was found that the pressure concentrated at the superior dome cartilage of femoral head and acetabulum in normal、dysplasia and low dislocation models. There were some redundant high pressure occurred at the area near posterior-superior rim only in the dysplastic and hip low dislocation models. In high dislocation model, there were high pressure occurred at the area near front-superior dome cartilage of femoral head, and there is no contact ressure occurred at the area of cartilage of real acetabulum. In the normal hip the hightest Von Mises stress of cartilage of femoral head and acetabulum were 2.02 MPa and 2.37 MPa; In the dysplasia hip the hightest Von Mises stress of cartilage of femoral head and acetabulum were 4.23 MPa and 5.43 MPa; In the low dislocation hip the hightest Von Mises stress of cartilage of femoral head and acetabulum were 8.45 MPa and 10.32 MPa; In the high dislocation hip the hightest Von Mises stress of cartilage of femoral head and acetabulum were 8.67 MPa and 0.59 MPa. The distribution of bone below cartilage in femoral head and acetabulum were like it of cartilage of femoral head and acetabulum, There were some redundant high pressure occurred at the area near posterior-superior rim only in the dysplastic hip and low dislocation models. In the normal hip the hightest Von Mises stress of femoral head and acetabulum below cartilage were 8.65 MPa and 2.52 MPa; In the dysplasia hip the hightest Von Mises stress of femoral head and acetabulum below cartilage were 8.92 MPa and 2.73 MPa; In the low dislocation hip the hightest Von Mises stress of femoral head and acetabulum below cartilage were 10.65 MPa and 4.02 MPa; In the high dislocation hip the hightest Von Mises stress of femoral head below cartilage and fake acetabulum were 8.17 MPa and 8.59 MPa.Conclusion An more precise 3D finite element model of nomal and adults developmental dysplasia of the hip acetabulum can be constructed with lamellar CT images and Mimics software.and also provides a reasonably and efective model for biomechanical analysis of adults developmental dysplasia of the hip.Part 2 Finite Element Analysis of Acetabular Ingression Insert in Total Hip ReplacementObjective To construct three-dimensional(3D) finite element models of acetabular ingression insert in total hip replacement , and analyze the stress distributions in the prothesis and to provide a theoretical basis for clinical work.Methods 3D models of the normal human acetabulum was constructed from lamellar CT images and acetabular prosthesis was developed through AUTOCAD by actual parameter. 3D finite element models of different center acetabular prothesis which were impacted according clinic operate were developed. With the application of hip joint loading, stress changes of prothesis were measured. The models were tested and their stress distributions were compared.Results The center of acetabular prothesis affected the resulting contact stress markedly.The peak contact stress values were found in the inner surface of polyethylene. The more distance ingression insert, the higher contact stress occure in polyethylene and linked part of prothesis neck and head. When acetabular in normal center, the hightest Von Mises stress in inner surface of polyethylene was 4.24 MPa and linked part of prothesis’neck and head was 17.02 MPa; When there is 3 mm between acetabular and iliopectineal line, the hightest Von Mises stress in inner surface of polyethylene was 4.35 MPa and linked part of prothesis’neck and head was 17.78 MPa , increased 2.59% and 4.47%; When acetabular prothesis attach iliopectineal line, the hightest Von Mises stress in inner surface of polyethylene was 4.70 MPa and linked part of prothesis’neck and head was 18.93 MPa, increased 10.85% and 11.22%; When acetabular prothesis overtopping iliopectineal line 3mm, the hightest Von Mises stress in inner surface of polyethylene was 4.97 MPa and linked part of prothesis’neck and head was 20.50 MPa, increased 17.22% and 20.45%; When acetabular prothesis overtopping iliopectineal line 6mm, the hightest Von Mises stress in inner surface of polyethylene was 5.67 MPa and linked part of prothesis’neck and head was 25.36 MPa, increased 33.73% and 49.00%.Conclusion When acetabular ingression insert in total hip replacement, higher contact stress values were occured in the inner surface of polyethylene and linked part of prothesis’neck and head . When prothesis exceed iliopectineal line, contact stress values were increased obviously.Part 3 Finite Element Analysis of Different Anteversion Insert Femoral Prothesis in Total Hip ReplacementObjective To construct three-dimensional(3D) finite element models of the different anteversion insert femoral prothesis in total hip replacement and analyze the stress distributions in femur and prothesis, and to provide a theoretical basis for clinical work.Methods 3D models of the normal human femur was developed through lamellar CT images and femoral prosthesis was developed through AUTOCAD according actual parameter. 3D finite element models of different anteversion insert femoral prothesis which were impacted according clinical operation. With the application of hip joint loading, quantitatively measure stress changes of femur and femoral prothesis were measured.Results (1) Compared with intact femur, insertion of femoral prothesis into the femoral canal decreased the proximal femoral stresses level, especially in calcar femorale and femoral tuberositas. However, the stress in the bone near the prosthisis distal end augmented. The stress of 0°and 30°anteversion angle insert femoral prothesis were smaller in calcar femorale, femoral tuberositas, higher in the bone near the prosthisis distal than that of 15°. (2)There were higher stress in femoral prothesis of 0°and 30°anteversion angle insert femoral prothesis than that of 15°. There were higher stress in interface-load of 0°and 30°anteversion angle insert femoral prothesis than that of 15°. (3) In the plane of osteotomy, insertion of femoral prothesis into the femoral canal decreased the proximal femoral stresses level, especially in calcar femorale and femoral tuberositas, the prothesis bear more stress. This phenomenon were obvious in the model of 0°and 30°anteversion angle insert. (4) The micromotion of prothesis were higher in the prothesis of 0°and 30°anteversion angle insert, compared with 15°anteversion angle insert.Conclusion Insertion of implants induced significant stress shielding in the proximal femur, especially at calcar femorale and femoral tuberositas, concentrated in the prosthesis distal end. In the 15°anteversion angle insert femoral prothesis model, the load distribution is even, micromotion is low, stability is high, so it has excellent biomechanics characteristics.更多还原