一种新型髋关节假体柄的生物力学设计

目的 基于一种新型髋关节假体柄设计,分析其在站立、行走、跑步和坐姿工况下的应力分布差异。 方法 基于人体 CT 数据,建立 7 组不同柄植入后的髋关节模型,利用有限元分析方法计算不同工况下假体柄和股骨应力情况。 结果 与植入传统假体柄相比,站立时新型假体柄植入后假体柄应力峰值降低 23%、股骨应力降低 72%。 7 种假体柄结果显示,假体柄高度为 86. 5 mm 的新型设计最符合患者需求。 多工况结果显示,患者处于坐姿,柄承受应力最小,使用寿命更长。 结论 新型假体柄有助于延长假体使用寿命,减小骨损伤风险。 髋关节假体模型为后期柄的设计及患者术后康复提供科学理论支撑。     

髋关节置换的三维有限元分析

目的本文建立股骨髋关节置换有限元模型，并进行了静力学模拟计算，寻求假体的材料属性对髋关节置换后产生的的影响。方法运用逆向工程与有限元的基本概念和理论，采用医学专用的建模软件mimics读取原始的股骨CT图片的dicom格式，完成股骨二维重建，然后根据股骨髓腔几何解剖状态应用CAD软件设计个性股骨假体。在ansys中对两个模型进行有限元装配，进行接触耦合分析!结果建立了精确的股骨模型和设计了个性假体。利用MIMICS基于灰度值进行赋材质，实现股骨有限元模型材料正确的非均匀及各向异性描述。成功模拟了三种假体材料置换后股骨的应力。结论三种材料中复合材料假体更接近人体生理环境，减弱了假体的应力遮挡，有利于力由假体传到到股骨上。为改进人工髋关节的设计、置换和提高人工髋关节寿命提供了一些有益的依据。研究结果表明这种假体设计和分析方法更为合理、可靠。     

人工髋关节假体的分类及设计

背景：人工髋关节置换是指用生物相容性良好的材料制成的一种类似人体骨关节的假体,置换被疾病或损伤所破坏的关节或关节平面,缓解关节疼痛、矫正畸形假体、改善关节的活动功能。 目的：对人工髋关节假体分类及设计研究文献的发展趋势进行多层次探讨分析。 方法：以电子检索方式对CNKI数据库学术期刊2002-01/2011-12收录有关人工髋关节假体分类及设计研究的文献进行分析,采用检索词为“髋关节置换;人工假体;假体设计;假体类型”,运用数据库的分析功能和Excel软件图表的功能分析数据特征。 结果与结论：CNKI数据库学术期刊2002/2011收录人工髋关节假体分类及设计研究的文献135篇,从文献数量上看处于上升趋势。以外科学分类的文献为主。《中国组织工程研究与临床康复》杂志因设有医学植入物栏目,在人工髋关节假体分类及设计研究中发表文献数量最多为33篇。上海交通大学是人工髋关节假体分类及设计研究的重点单位,王成焘教授是从事此研究的重要核心作者。文献关键词显示人工髋关节假体设计和类型主要考虑髋关节、股骨的生物力学方面问题,以及人工髋关节假体有限元分析、翻修、假体无菌性松动等。     

人工髋关节假体的设计及界面应力分析

背景：骨正确选择与宿主相容性良好的假体是保证全髋关节置换成功的重要因素,与置换后人工关节的生物力学性能和使用寿命有着密切的关系。 目的：总结人工髋关节假体的研究进展,分析人工髋关节假体设计与界面力学对假体植入后生物相容的影响。 方法：采用电子检索的方式在万方数据库中检索2000-01/2011-12有关髋关节假体材料及人工髋关节置换先关的研究,关键词为“髋关节、假体、置换、生物力学”。排除重复研究、普通综述或Meta分析类文章。 结果与结论：共纳入34篇文献进行评价。全髋关节置换后人工关节的生物力学性能与使用寿命有着密切的关系,假体受力可以分解为正应力和剪切应力两部分,正应力有益于假体的固定和力的传递,而剪切力会导致假体松动。假体周围骨质及骨量的变化,假体松动、脱位,假体周围骨折,材料磨损及假体周围感染是髋关节置换后影响中远期效果的常见并发症。目前还缺乏生物相容性好、生物力学相容性好的理想假体,人工髋关节设计、制造工艺、假体材料的耐磨性与界面应力等生物力学性能均有待于进一步提高,从而更好地适应宿主。     

人工髋关节活体有限元建模及力学分析

背景：有限元分析最为广泛地应用于人工髋关节置换的研究,能够反映人工髋关节置换前后的应力分布情况。 目的：通过CT扫描图像建立人工髋关节置换后的三维有限元模型,分析假体和股骨的力学分布,提供研究活体内假体的评估方法。 方法：选非水泥型人工髋关节假体置换后患者1例,64排CT扫描髋关节,通过三维建模软件建立三维有限元模型,加载载荷1 500 N,分析假体和股骨的应力分布,并与体外建模和正常股骨有限元模型比较。 结果与结论：应用患者人工髋关节置换后CT扫描图像建立的三维有限元模型,加载后应力主要分布在股骨干上端1/3处,在股骨假体柄颈结合处,假体外侧,假体的远端与股骨接触处,是假体置换后应力在体内传递的真实反映。结果说明活体髋关节建模优于体外建模,不改变假体在体内的位置,人工髋关节活体建模是假体评估新方法。     

股骨颈保留型人工全髋关节置换后的应力分析

背景：股骨颈保留型(Collum Femoris Preserving,C.F.P)假体为意大利骨科医生Pipino与德国LINK公司联合设计开发。该假体手术操作手册中推荐截骨平面是否适合国人股骨结构特点以及所采用截骨方式是否会引起假体以及股骨应力发生变化,目前尚未见研究报告。 目的：通过临床病例回顾和三维有限元模型分析股骨颈保留型人工全髋关节置换的临床疗效以及应力分布变化。 方法：①回顾分析36例股骨颈保留型全髋关节置换及36例普通生物型全髋关节置换患者临床资料,通过Harris评分、目测类比评分、置换前后偏心距变化、IDES-Engh放射学及并发症等指标评价疗效。②建立两种不同截骨平面股骨颈保留型全髋关节置换有限元分析模型,分析股骨转子间窝上1.5 cm及头颈交界处为截骨平面带来的偏心距差异、股骨以及假体应力分布变化。 结果与结论：①头颈交界处为截骨平面的股骨颈保留型全髋关节置换,短期随访临床疗效优良,与普通生物型无明显差别。②有限元分析显示：头颈交界为截骨平面与转子间窝上1.5 cm为截骨平面比较,偏心距增大,假体及股骨所受应力增大,但应力分布相同。中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程全文链接：     

组配式髋表面置换股骨头假体植入后股骨近段应力变化的有限元分析

目的研究组配式髋表面置换股骨头假体植入后,股骨近段及假体周围骨质区应力分布的变化。方法建立正常股骨近段、传统表面髋置换假体(本实验选用Wright假体)、组配式表面髋假体三维有限元模型,关节加载后分析假体植入前后股骨近段应力分布变化,并对股骨近端假体周围区域骨质应力分布进行分区量化研究。结果传统假体沿着杆体周围骨质上有多处的应力集中区域,在股骨颈的下方(4、10区)应力明显增加,股骨头上方假体杯下缘(1、7区)应力遮挡;组配式假体螺钉周围骨质上虽有应力集中,但是数值相对较小,股骨颈下方(4、10区)应力分布接近正常股骨。结论与传统表面髋假体置换相比,组配式假体在股骨颈下方区域有较好的应力分布,接近正常股骨,降低了股骨颈骨折的危险。     

人工髋关节置换前后股骨及假体的生物力学分析

目的:研究人工髋关节置换前后股骨及假体的应力分布以及假体设计参数对应力的影响。方法:建立股骨和假体有限元模型,分析在步行峰值关节载荷和主要肌肉载荷作用下,完整股骨和置换后股骨及假体的应力水平。结果:完整股骨中上部内侧受压应力,外侧受张应力,中下部外侧受压应力,内侧受张应力,股骨应力峰值位于中下部;置换后股骨受力总体模式不变,近端应力遮挡显著。随颈干角增加,假体及股骨应力水平降低;柄长对假体应力影响不大,股骨上的应力随柄长增大略有增加。结论:假体设计时可适当增大颈干角,在骨组织条件允许的情况下可适当增加假体柄长,以减轻术后的应力遮挡效应。     

髋关节表面置换术中可视化虚拟技术建立股骨头假体植柄通道的模拟研究

目的：通过计算机辅助对股骨头假体植柄通道的模拟研究,为人工全髋关节表面置换术股骨头假体植入方案提供更为科学的评估方法和预测手段。方法：选择无明显髋关节疾病的15具成人尸体标本,对整个骨盆进行连续CT扫描,将CT原始数据导入Mimics 10．1软件,重建出股骨近端三维模型。通过计算股骨头中心和股骨近端中心线,建立股骨颈轴线并确定股骨头假体最佳植柄通道,进行虚拟植入和三维可视化分析。结果：各维度观察股骨头假体植柄通道通过股骨头中心,位于股骨颈的中央。股骨头定位针模拟植入后假体柄干角与术前颈干角相比呈轻度外翻位,侧方偏移和水平偏移度较小,达到预期植柄方位的要求。结论：计算机辅助可以准确建立股骨头假体植柄通道并进行可视化分析,为个体化髋关节表面置换术提供了科学的评估方法和预测手段。     

复合材料股骨头假体三维有限元分析

目的;分析不同材料股骨头假体置换后的应力关系。方法：应用三维有限元理论分析碳纤维聚砜（CRF／PSF）复合材料与钴铬钼（CoCrMo)合金假体置换,在施加载荷,动静态下的应力分布。结果：CRF／PSF组股骨受力达85%-98%,而CoCrMo只有50％;在假体的表面受力前者只有10％左右,后者则达50％。结论：低弹CRF／PSF复合材料假体能显著降低应力遮挡、应力集中,从而推断低弹材料具有高疲劳强度,能达到较好的力学相容性。     

不同材料人工髋关节假体对骨界面应力分布及生物力学的影响

BACKGROUND: During joint replacement, different materials of prosthesis can be used. Different prosthesis can produce different effects and the stress distribution of bone interface. OBJECTIVE: To explore the effects of different materials on the stress distribution and biomechanics of the bone interface of artificial hip joint. METHODS: The CT scan of the hip was carried out. The image data were saved in DICOM format and processed by MIMICS software. The 3D finite element model of the femur was obtained by ANSYS. A three dimensional finite element model of the femur was made with the material properties of the femur. Three kinds of different replacement prosthesis materials (Co Cr Mo alloy, titanium alloy and composite materials) were selected, and the specific requirements of the actual joint replacement were selected, and different types of prosthesis were designed in CAE software. In the STL format, the prosthesis model was imported into MIMICS, and the femur and prosthesis were assembled. The stress status of different prosthesis was analyzed, and the stress shielding rates of exterior and interior sides of middle and lower parts of the femur, right to and 30 mm below lesser trochanter and right to lesser trochanter of the proximal femur were calculated. RESULTS AND CONCLUSION: Through three-dimensional finite element analysis, a direct and accurate model of the femur and the three-dimensional model of the prosthesis were established. According to the actual situation, material assignment of the femoral three-dimensional finite element model was conducted to obtain the corresponding model. Thus, the properties of different materials of the femur were shown visually. The femoral stress of cobalt chromium molybdenum alloy, titanium alloy, and composite material was simulated after replacement. Results found that the stress shielding rate can decrease in the middle and lower parts of the femur. After replacement, the femoral stress is higher than that of the intact femur. The experimental results show that the stress shielding of the joint was performed after joint replacement with Co Cr Mo alloy, titanium alloy and composite materials. Among them, the composite material is more close to the actual physiological environment of the human body, and it can better reduce the stress shielding effect, and is beneficial to the stress from the prosthesis to the femur.      

人工股骨头置换治疗严重股骨转子间骨折的有限元分析

目的　建立股骨转子间骨折、人工关节假体的三维数字模型,应用有限元对人工股骨头置换术后的股骨应力分布进行分析,评价置换术后的初始稳定性。 方法　利用螺旋CT对志愿者的左侧股骨进行断层扫描获取图像数据,经Mimics软件和Unigraphics建模软件处理,重建股骨三维模型。在此基础上,建立股骨转子间骨折、标准柄股骨假体三维实体模型,最后利用有限元分析软件Ansys10.0建立人工股骨头置换术治疗股骨转子间骨折的三维有限元模型,并对该模型进行生物力学分析。 结果　应力分析显示：正常股骨的应力由近端向远端逐渐上升,并于中下段达到最高。同时人工股骨头假体的应力集中于中段,与正常股骨的应力变化基本一致。人工股骨头置换没有改变股骨总体的应力模式,股骨距部位未见明显的应力集中区,依然是由近端向远端逐渐增加,应力峰值区域亦于全长股骨的中下段。 结论　标准柄人工股骨头置换治疗股骨转子间骨折不会引起股骨应力分布的明显改变,可以获得重建后的初期稳定。     

3D Finite Element Analysis of a Man Hip Joint Femur under Impact Loads

Objective： The biomechanical characters of the bone fracture of the man femoral hip joint under impact loads are explored. Methods ：A biosystem model of the man femoral hip joint by using the GE （ General Electric） lightspeed multi-lay spiral CT is conducted. A 3D finite element model is established by employing the finite element software ANSYS. The FE analysis mainly concentrates on the effects of the impact directions arising from intense movements and the parenchyma on the femoral hip joint on the stress distributions of the proximal femur. Results：The parenchyma on the hip joint has relatively large relaxation effect on the impact loads. Conclusion：Effects of the angle δ of the impact load to the anterior direction and the angle γ of the impact load to the femur shaft on the bone fracture are given;δ has larger effect on the stress and strain distributions than the angle γ,which mainly represents the fracture of the upper femur including the femoral neck fracture when the posterolateral femur is impacted, consistent with the clinical resuits.     

Stress Analysis and Shape Design of a Femoral Hip Prosthesis

Objective: To study the stress distribution of the femoral hip prosthesis after the hip joint replacement. Methods: After the hip joint replacement, when the femur and prosthesis are considered as concentric cylinders with perfectly banded interface, a relatively perfect theoretical model of simulating the interfacial stress transfer is established. Results: The maximum interfacial shear stress occured at Z=0. At the cross-section of the femoral neck, interfacial shear stress decreased exponentially with the increases of the Z. Shear stress became very small at Z＞0.1 m, which meant that the shear stress at the far end of the femoral hip prosthesis was very small. In order to avoid the stress concentration and femoral hip prosthesis sinking, interfacial stress must remain constant and balanced with the pressure load at Z=0. The radius of the femoral hip prosthesis changed with interfacial shear stress. The maximum value of the radius occured at Z=0, then it decreased at m. Specially, a=18.2 mm at Z=10 mm, a=5.36 mm at Z=98 mm, these are ideal radius. Conclusion: A theoretical model of simulating the interfacial stress is established when the femur and prosthesis are considered as concentric cylinders. The distributions of the interfacial shear and radial stresses with the axial positions are obtained. A theoretical reference for the design of the prosthesis is provided.     

人工股骨头置换治疗骨质疏松股骨转子间不稳定骨折的有限元应力分析

背景：通常的力学实验手法基本上无法直接应用于人体且模型间可比性低,对人体的力学行为进行有限元数值模拟就成为深化对人体认识的一种有效手段。 目的：运用计算机模拟骨质疏松股骨转子间不稳定型骨折人工股骨头置换,并做置换后股骨及假体的应力分析,评估置换后假体的初始稳定性。 方法：对志愿者双下肢进行薄层CT扫描获得股骨数据,图像处理软件Mimics11.1进行图像处理后数据导入建模软件UG4.0建立股骨三维模型;假体柄与股骨间行布尔运算,分为正常关节置换组和转子间骨折人工关节置换组,观察两组材料赋值、定义接触、受力加载、应力分析等情况。 结果与结论：人工关节置换改变了股骨的受力方式,股骨转子间骨折关节置换后的假体稳定性较好,在正常载荷下人工关节稳定。     

髋关节置换前后不同步态下股骨应力分布

目的探讨人工髋关节置换(total hip replacement,THR)前后慢走及上下楼梯两种不同步态下股骨的生物力学性能,为髋关节假体的优化设计和制造提供理论基础。方法建立人工髋关节股骨的三维有限元模型,并进行有效性验证;计算慢走和上下楼梯时THR前后股骨的应力分布及应力遮挡率。结果慢走运动时,THR前股骨应力由近端到远端逐渐递增,在股骨中下段达到最大,最大应力为90.6 MPa;THR后股骨出现应力遮挡现象,股骨的应力幅值有所下降,最大应力为82.5 MPa,股骨近端假体周围大转子附近股骨遮挡率最大,总体遮挡率为14.9%~99.0%。此外,假体颈部出现过大的应力集中现象。上下楼梯运动时,股骨应力分布的变化规律与慢走运动时大体相似,但应力遮挡效应更为明显。结论植入假体后,上下楼梯时股骨近端出现较大应力遮挡,并且假体自身出现过大应力集中,会影响THR手术质量,建议病人在术后应尽量减少关节角变化较大的运动。     

骨质疏松股骨转子间不稳定型骨折人工股骨头置换的三维有限元应力分析

BACKGROUND: Artificial femoral head replacement provides a new idea for the repair of unstable intertrochanteric fracture. Artificial prosthesis replacement may affect original femoral biomechanical stability and lead to a variety of adverse consequences.  OBJECTIVE: To analyze the stress distribution of femoral head replacement in the treatment of unstable femoral intertrochanteric fractures with three-dimensional finite element analysis. METHODS: One male old volunteer was randomly selected from population who underwent health examination. The left femur was scanned with spiral CT, and the three-dimensional finite element models of the human femur and prosthesis were established. The three-dimensional finite element model was used to simulate the actual working conditions of human climbing stairs, and the stress distribution of the bone channels around the surface of the femur and the prosthesis was analyzed with three-dimensional finite element analysis. RESULTS AND CONCLUSION: Under normal condition, the stress of the human femur was in a consistent state. Stress changed gradually from the proximal end to the distal end. The stress of the prosthesis was concentrated in the middle section. The prosthesis of inner stress distribution was analyzed to obtain stress distribution of prosthesis and femur cancellous bone interface. The analysis found that stress change trend was consistent. The results suggest that artificial femoral head replacement does not have a significant effect on the overall stress distribution of the human femur, and the overall stress distribution does not change, and the maximum stress region is located in the middle of the whole femur. After the reconstruction, the stress concentration of the femur is not observed.