膝关节计算机三维模型的建立

目的：通过三维激光扫描仪对膝关节几何形态进行三维重建，建立膝关节计算机三维模型，探讨此方法对膝关节相关研究的指导意义。方法：将膝关节两端进行包埋并打好标记物，利用三维扫描系统对膝关节屈曲不同角度扫描后进行三维重建，建立膝关节的动态运动仿真模型。结果：建立了膝关节三维计算机模型，并利用三维模型进行了膝关节运动及生物力学的初步实验。结论：该模型为膝关节相关研究提供一种良好的手段。     

膝关节生物力学模型研究现状

膝关节是人体最重要的关节之一。对膝关节的生物力学性质和行为的正确认识有助于临床上各类膝关节伤病的治疗。模型是研究生物力学系统的有效手段，本文回顾了近年来国内外学者提出的若干膝关节力学模型，分析了其优点及局限性。提出了膝关节模型的发展趋势，为进一步探讨膝关节模型提供了参考和借鉴。     

膝关节关节软骨的三维构建

目的:构建膝关节关节软骨的三维模型,为开展膝关节数字医学研究进行模型构建的探索。方法:人体成年新鲜膝关节标本1例,行CT、MRI扫描,利用三维重建软件Mimics及逆向工程软件Geomagic对图像进行三维重建及图像配准,构建膝关节骨、关节软骨结构。结果:利用Mimics 10.01软件构建关节软骨的三维模型,并形成骨-关节软骨复合模型,导入Geomagic软件中与CT构建的骨三维模型相配准,再次导入CT影像中进行逐层微修饰,验证关节软骨分割效果。最终建立具有骨、关节软骨的三维膝关节模型。结论:三维图像重建技术与图像配准技术可将CT、MRI图像两者结合起来,发挥其各自优势,构建出形态较好的膝关节三维模型。     

基于膝关节三维模型的髌股关节动力学特性研究

目的构建有效的膝关节三维模型以计算髌股关节动力学参数。方法基于CT图像处理和CAD技术, 重建包括股骨下端、胫骨上端及髌骨的膝关节的骨骼三维模型,并定义髌股关节运动起重要作用的股四头肌直线模型、韧带及其它软组织的非线性弹性纤维束模型,以股四头肌肉力为输入控制变量。结果构造出一个有效的膝关节三维模型。结论该模型可以有效的计算髌股关节动力学参数。     

人体全膝关节精细有限元模型建立及有效性验证

近年来利用数字三维模型对人体全膝关节进行生物力学分析在国内外迅速发展,但是缺乏完整精细的膝关节有限元模型;同时对所建立模型的验证也比较单一,仅从韧带或者软骨受力单方面进行有效性的验证,导致模型的实用性和广泛性受到限制。目的以一种创新、高效的方法三维重建精细人体膝关节有限元模型,包括股骨、胫骨、髌骨、腓骨、股骨软骨、胫骨软骨、髌骨软骨、腓骨软骨、半月板、交叉韧带、侧韧带、髌韧带等组织结构,并对整体模型有效验证。方法利用CT和MRI医学影像,使用Mimics、3-Matic、Geomagic、Solidworks、Abaqus软件获得完整、精细的人体膝关节模型;在内外髁中点施加1 000 N竖直向下载荷,分析膝关节内外间室的力学分布及软骨的力学响应;以胫骨平台髁间隆起为参考施加134 N前向推力,模拟临床中的抽屉实验(ADT),获取各韧带组织的生物力学响应,并与现有人体实验及模型对比。结果 1 000 N载荷下,股骨软骨最大Mises应力值为2.514 MPa,半月板最大Miese应力值为7.693 MPa,胫骨软骨最大Mises应力值为1.848 MPa,均分布于膝关节的内侧;内外侧软骨接触面积分别为476.080 8 mm~2和338.446 8 mm~2;内外腔室分别承担总载荷的60.57%和39.43%。134 N载荷下,胫骨平台前端的位移量为5.687 mm;前十字交叉韧带(ACL)最大Mises应力值为28.030 MPa,后十字交叉韧带(PCL)最大Mises应力值为16.730 MPa,内侧副韧带(MCL)最大Mises应力值为4.511 MPa,外科韧带(LCL)最大Mises应力值为3.751 MPa;交叉韧带与股骨止点的最大Mises应力值为15.270 MPa。结论建立的精细膝关节三维模型很好地重塑了人体膝关节相关生物力学特性;该精细膝关节模型仿真结果与现有实验数据非常接近,证明了模型的有效性;完整、有效的精细全膝关节有限元模型将为植入物手术、人体运动分析、康复研究等打下基础。     

基于MRI建立膝关节前交叉韧带三维数字化模型

背景：近年来有关膝关节前交叉韧带三维数字化模型的研究在国外发展迅速,但在国内,未见对包括全膝关节及前交叉韧带在内的三维数字化模型进行基础解剖研究的报道。 目的：评估运用MRI二维图像及MIMICS软件建立膝关节及前交叉韧带三维数字化模型的真实性及可靠性。 方法：选择20例新鲜成人尸体正常膝关节标本,利用MRI对标本进行二维扫描,获得层厚为1.0 mm的连续图像资料,将该资料以DICOM格式导入计算机并利用MIMICS软件进行三维重建,建立包括股骨远端、胫骨近端、前交叉韧带、半月板、髌骨及腓骨等在内的双膝关节三维实体数字化模型,利用测量软件测量相关指标;同时对尸体标本进行解剖并测量膝关节前交叉韧带的相关参数,与模型所测指标行配对比较。 结果与结论：尸体标本测量数据与三维实体数字化模型测量数据的结果差异均无显著性意义(P > 0.05)。提示利用MRI采集获得的人体膝关节及前叉韧带图像数据可以建立较为真实可靠的膝关节及前交叉韧带三维实体数字化模型。     

应用逆向工程技术测量人膝关节内外侧间室间隙和体积

背景：膝关节是人体骨骼中形态及结构最为复杂的部分,临床上常使用X射线片反映膝关节间隙狭窄程度。但X射线片是将三维的关节结构进行二维投射,因此关节拍摄定位的不同会影响测量结果,很难保证重复测量的准确性。 目的：建立膝关节间隙三维模型并测量其距离和体积,为后续的模型、生物力学及相关临床研究提供基础。 方法：基于逆向工程原理,采用膝关节CT断层图像,使用Mimics进行膝关节和内侧间室三维结构重建,最后导入Geomagic Studio对模型进行光滑处理并计算膝关节内、外侧间室体积。 结果与结论：利用膝关节CT断层图像分别重建出膝关节三维模型的骨性结构如股骨、胫骨、腓骨,并成功构建出膝关节间隙模型。构建的膝关节三维模型和间隙模型可以任意角度或单独观察,并可以进行体视学测量。发现膝关节内外侧间隙虽然距离有差异,但体积接近,说明通过计算膝关节内、外间室的体积,可以全面的反映膝关节间隙的狭窄程度。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     

一种组合式个性化人工膝关节假体数字化设计方法

目的 提出一种组合式个性化人工膝关节假体结构,解决膝关节股骨肿瘤保肢手术由于截骨位置差异性较大,很难采用标准型人工膝关节假体满足个性化需求的问题。方法 首先将患部关节区域CT数据进行三维重建,并利用MRI增强扫描技术建立肿瘤的三维模型,再通过肿瘤模型与患部关节模型进行位置匹配,在三维模型上确定手术截骨位置,根据截骨尺寸设计个性化的股骨柄与标准股骨髁假体进行有效组合,形成一种组合式个性化人工膝关节假体。结果 根据本文设计方法的结果加工成型,骨科临床医生分析膝关节假体结构与人体膝关节生理结构相符,达到个性化假体设计要求,能够重建患者膝关节功能。结论 这种膝关节假体结构有利于降低个性化膝关节假体设计加工成本,缩短设计加工周期,有望提高患者生命质量。     

有限元数字化膝关节模型构建的研究与应用

背景：膝关节的解剖结构和力学特征决定它的生物力学特性,应用有限元分析方法对膝关节生物力学机制及损伤机制进行研究,可以有效地指导预防和治疗膝关节疾患。 目的：评价有限元数字化膝关节模型构建的研究和应用价值。 方法：以“CT,MRI,膝关节,有限元,模型构建”为关键词,采用计算机检索2005年1月至2011年11月维普数据库和万方数据库相关文章。纳入与膝关节模型构建及应用相关的文章;排除重复研究或Meta分析类文章。以9篇文献为重点讨论CT、MRI和有限元模型构建在膝关节中的研究和应用。 结果与结论：CT、MRI所采集到的DICM图像在有限元模型构建中各具优缺点,有限元模型合理应用,能够为膝关节的手术提供更全面、更可靠的影像学资料,临床医师可根据模型进行手术方案设计,模拟手术流程,显著降低了手术风险,减少了患者的痛苦。     

膝关节骨性关节炎生物力学模型及其软骨表面应力分析

背景：膝关节骨性关节炎主要以软骨退变,骨质增生进而影响到关节周围软组织致关节疼痛,负重后加重以及后期致关节变形的慢性疾病。 目的：实验收集膝关节骨性关节炎患者及正常人的膝关节影像学参数,再先后导入各种软件建立模型,然后在模型上模拟膝关节下蹲动作,并收集下蹲过程中膝关节骨性关节炎患者及正常人膝软骨表面的应力数据,并将两者进行对比从而得出膝关节骨性关节炎患者软骨表面应力特征。 方法：收集膝关节骨性关节炎患者及正常人各30例,通过影像学CT,MRI检查获得数据,将得到的数据通过Mimics软件、Simpleware软件分析后建立模型,通过模型获得膝关节软骨应力相关数据,最后进行膝关节骨性关节炎患者与正常人数据的对比分析,分析总结得出膝关节骨性关节炎患者关节软骨的应力特点。 结果与结论：膝关节骨性关节炎患者从站立到下蹲过程中膝软骨表面应力一般呈现非线性递增趋势。膝关节骨性关节炎患者下蹲过程中膝软骨表面中间外侧应力应力高于正常人体组(P < 0.05),而其下蹲过程中膝软骨表面靠近远端应力及前后侧应力与正常人相比差异无显著性意义(P > 0.05)。结果证实,成功建立膝关节骨性关节炎肌骨模型和有限元模型,建立的模型更接近真实膝关节的运动特征,通过模型为膝关节骨性关节炎疾病提供膝部组织定量的生物力学数据。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

前交叉韧带力学特性差异对膝关节有限元仿真结果的影响

目的研究不同前交叉韧带力学特性对膝关节有限元模拟结果产生的影响。方法基于医学图像数据重建包含主要解剖结构在内的膝关节三维有限元模型,并考虑韧带的横观各向同性特性;用同一种韧带本构方程对3种不同前交叉韧带应力应变力学实验曲线进行参数拟合,对比不同的前交叉韧带力学参数对膝关节运动学和生物力学性能的影响。结果不同的前交叉韧带力学特性会得到不同的膝关节位移结果,前交叉韧带内的应力及应变大小有很大变化,但分布的趋势基本相同。结论选取不同前交叉韧带力学特性曲线会影响膝关节有限元分析的仿真结果,今后在关节组织力学性能的设置、模型的构建及验证中要足够重视。     

Influence of Anthropometric and Mechanical Variations on Functional Instability in the ACL-Deficient Knee

Individual variations in joint anatomy, tissue mechanical properties, and muscle strength of the knee are believed to affect the clinical outcome of ACL-deficient patients, but the effects have not been studied systematically. The impact of individual anthropometric and mechanical variation on functional stability of the ACL-deficient knee was investigated in this study using a two-dimensional mathematical knee model. The model included the tibiofemoral and the patellofemoral articulations, four ligaments, the medial capsule, and four muscle units surrounding the knee. Simulations were conducted to determine tibial anterior translation as well as tibiofemoral and patellofemoral joint loading at a single selected position during early stance phase of gait. Incremental hamstring muscle forces were applied to the modeled ACL-deficient knee in order to examine the level of the hamstring muscle forces required to prevent abnormal tibial anterior translation relative to the femur. Simulations were repeated using incremental variations in the selected anthropometric and mechanical properties of the ACL-deficient knee. It was found that bony geometry of the knee joint, especially the slope of tibial plateau, strongly affected both the tibial translations in the ACL-deficient knee and the effectiveness of the hamstring muscles to compensate for the ACL deficiency. For instance, simulations indicated that, due to ACL deficiency, the tibial anterior displacement increased by 9.1 mm for a tibial slope angle of 4° compared to 15.2 mm for a tibial slope angle of 12°. Future outcome studies for ACL-deficient knee may be required to include individual anthropometric and mechanical parameters of the knee as covariants. © 2003 Biomedical Engineering Society. PAC2003: 8719Rr, 8719Ff, 8719St     

人体膝关节韧带生物力学研究进展

韧带是稳定膝关节的主要组成部分。如何在生物力学模型中模拟韧带将会影响膝关节动力学特性以及韧带力．韧带应变和接触力分布的计算。本文就韧带在生物力学模型中的简化方法及其力学参数的选择以作一综述．并提出建模的具体方法。     

跳跃运动中不同护膝条件下膝关节半月板应力场的数值研究

目的 采用数值模拟方法,建立人体膝关节肌骨系统生物力学模型,并将人体动力学模型模拟跳跃运动时所获得的运动学和动力学信息作为模型驱动数据,进而分析不同热力耦合护膝条件下膝关节半月板的应力场分布特征。方法 基于受试者CT与MRI断层扫描图像,构建包括骨、关节软骨、半月板、韧带和膝关节外围软组织的较真实人体膝关节模型,依据跳跃运动全周期分析选择蓄力起跳、落地冲击两个半月板损伤风险较大的位姿步态进行模拟,分析4种不同热力耦合护膝条件下膝关节半月板的应力场特征,讨论半月板峰值应力及其应力集中区域的变化,探究半月板损伤以及佩戴护膝的防护功效和力学依据。 结果 膝关节内侧半月板前角是应力集中的易受损区域;在热力场耦合护膝条件下,内侧半月板应力集中区域由其狭长且薄弱的前角转移至其较为宽厚的中部,且峰值应力显著降低;内、外侧半月板的峰值应力接近,表明两者共同承担外载,且半月板应力集中区域面积减小。结论 热力场耦合护膝对于膝关节半月板的损伤具有良好防护作用。数值模拟研究结果可以为热力多功能护膝的设计提供理论支撑和技术指导。     

Computational modeling of a forward lunge: towards a better understanding of the function of the cruciate ligaments

This study investigated the function of the cruciate ligaments during a forward lunge movement. The mechanical roles of the anterior and posterior cruciate ligament (ACL, PCL) during sagittal plane movements, such as forward lunging, are unclear. A forward lunge movement contains a knee joint flexion and extension that is controlled by the quadriceps muscle. The contraction of the quadriceps can cause anterior tibial translation, which may strain the ACL at knee joint positions close to full extension. However, recent findings suggest that it is the PCL rather than the ACL which is strained during forward lunging. Thus, the purpose of the present study was to establish a musculoskeletal model of the forward lunge to computationally investigate the complete mechanical force equilibrium of the tibia during the movement to examine the loading pattern of the cruciate ligaments. A healthy female was selected from a group of healthy subjects who all performed a forward lunge on a force platform, targeting a knee flexion angle of 90°. Skin-markers were placed on anatomical landmarks on the subject and the movement was recorded by five video cameras. The three-dimensional kinematic data describing the forward lunge movement were extracted and used to develop a biomechanical model of the lunge movement. The model comprised two legs including femur, crus, rigid foot segments and the pelvis. Each leg had 35 independent muscle units, which were recruited according to a minimum fatigue criterion. This approach allowed a full understanding of the mechanical equilibrium of the knee joint, which revealed that the PCL had an important stabilizing role in the forward lunge movement. In contrast, the ACL did not have any significant mechanical function during the lunge movement. Furthermore, the results showed that m. gluteus maximus may play a role as a knee stabilizer in addition to the hamstring muscles.     

Effects of the material properties of a focal knee articular prosthetic on the human knee joint using computational simulation

BackgroundLocalized cartilage defects are related to joint pain and reduced function to the development of osteoarthritis. The mechanical properties of the implant for treatment do influence its longevity. Therefore, we aimed to evaluate the effect of material properties' variations of anatomically shaped focal knee implants in the knee joint using numerical finite element analysis.MethodsComputational simulations were performed for different cases including an intact knee, a knee with a focal cartilage defect, and a knee fitted with a focal articular prosthetic having three distinct mechanical properties: cobalt–chromium, pyrolytic carbon, and polyethylene. Femoral cartilage, tibial cartilage, and menisci contact pressures were evaluated under the load. In addition, bone stress was evaluated to investigate the stress shielding effect.ResultsCompared with the intact model, the contact stress of the focal implant model was increased; on the femoral lateral cartilage by 14%, on medial and lateral tibial cartilages by nine percent and 10%, on medial and lateral menisci by 23% and 20%. In contrast, the focal implant model had no effect on the menisci but contact stress on the tibial cartilage increased compared with the intact model. The BioPoly model showed the lowest contact stress on femoral and tibial cartilages. Additionally, the cobalt–chromium model showed the lowest bone stress that improved the load-sharing effect.ConclusionsThe results suggested that implant material properties are an important parameter in the design of a focal implant. The polyethylene model potentially restored the intact knee contact mechanics and it reduced the risk of physiological damage to the articular cartilage.     

Processing of nociceptive mechanical and thermal information in central amygdala neurons with knee-joint input.

Pain has a strong emotional dimension, and the amygdala plays a key role in emotionality. The processing of nociceptive mechanical and thermal information was studied in individual neurons of the central nucleus of the amygdala, the target of the spino-parabrachio-amygdaloid pain pathway and a major output nucleus of the amygdala. This study is the first to characterize nociceptive amygdala neurons with input from deep tissue, particularly the knee joint. In 46 anesthetized rats, extracellular single-unit recordings were made from 119 central amygdala neurons that were activated orthodromically by electrical stimulation in the lateral pontine parabrachial area and were tested for receptive fields in the knee joints. Responses to brief mechanical stimulation of joints, muscles, and skin and to cutaneous thermal stimuli were recorded. Receptive-field sizes and thresholds were mapped and stimulus-response functions constructed. Neurons in the central nucleus of the amygdala with excitatory input from the knee joint (n = 62) typically had large symmetrical receptive fields in both hindlimbs or in all four extremities and responded exclusively or preferentially to noxious mechanical stimulation of deep tissue (n = 58). Noxious mechanical stimulation of the skin excited 30 of these neurons; noxious heat activated 21 neurons. Stimulus-response data were best fitted by a sigmoid nonlinear regression model rather than by a monotonically increasing linear function. Another 15 neurons were inhibited by noxious mechanical stimulation of the knee joint and other deep tissue. Fifteen neurons had no receptive field in the knee but responded to noxious stimulation of other body areas; 27 nonresponsive neurons were not activated by natural somesthetic stimulation. Our data suggest that excitation is the predominant effect of brief painful stimulation of somatic tissue on the population of central amygdala neurons with knee joint input. Their large symmetrical receptive fields and sigmoid rather than monotonically increasing linear stimulus-response functions suggest a role of nociceptive central amygdala neurons in other than sensory-discriminative aspects of pain.     

运动学对线和机械力学对线指导全膝关节置换效果的Meta分析

文题释义： 运动力学对线：是行全膝关节置换时的一种下肢对线方法,尽可能还原膝关节患关节炎前的运动状态。 机械力学对线：该对线方法已指导全膝关节置换手术近30年,机械力学对线技术的目标是恢复髋-膝-踝0°角,从而使整个下肢恢复到中立位,近些年研究发现该方法指导的全膝关节置换术后1/5患者对置换效果不满意。 背景：机械力学对线技术虽然保证了膝关节假体的长期生存率,但是仍有部分全膝关节置换患者对置换效果及术后膝关节功能不满意。 目的：采用Meta分析的方法评价运动学对线技术和机械力学对线技术指导全膝关节置换的效果。 方法：检索运动学对线和机械力学对线指导全膝关节置换的临床对照研究文献,检索范围包括中国生物医学文献数据库、万方数据、中国知网、维普数据、PubMed、Cochrane图书馆及Embase,检索年限为建库日期至2019年7月。对检索到的文献进行筛选、质量评价及数据提取,并采用Review Manager 5.3软件进行统计分析。 结果与结论：①共纳入12篇文献,包括945例患者,其中运动学对线组470例,机械力学对线组475例;②荟萃分析结果显示,手术时间方面运动学对线组比机械力学对线组更短[MD=-15.44,95%CI(-27.16,-3.71)],西安大略和麦克马斯特大学骨关节炎指数运动学对线组优于机械力学对线组[MD=-8.40,95%CI(-15.39,-1.40)],牛津大学膝关节评分运动学对线组优于机械力学对线组[MD=4.72,95%CI(0.24,9.21)],机械力学对线组术后的机械外侧股骨远端角及机械内侧胫骨近端角显著大于运动学对线组,以上研究P均< 0.05;③运动学对线组与机械力学对线组在平均住院日、出院前最远行走距离、膝关节协会评分、膝关节伸直角度、术后并发症方面差异无显著性意义(P均> 0.05);④提示运动学对线指导全膝关节置换后的膝关节功能优于机械力学对线,但影像学和围术期结果类似,且术后未增加并发症发生率。说明运动学对线可作为一种下肢力线对线方法来指导全膝关节置换。 ORCID: 0000-0002-3786-6305(赵春涛) 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     

人体膝关节有限元动力学分析模型的建立与验证

根据乘员碰撞事故中人体膝关节的生物力学响应特性,应用有限元(FE)方法和碰撞模拟技术,构建了一个人体膝关节模型。模型按人体解剖学结构构建,由股骨内、外侧髁,胫骨内、外侧髁,腓骨小头、髌骨、软骨、半月板以及主要韧带构成。通过比较模型仿真和尸体碰撞实验在轴向载荷条件下膝关节受刚性碰撞的响应结果,验证了模型的有效性。该模型为研究人体膝关节损伤机理提供了可靠的基础数据,并可应用于乘员损伤防护装置的设计和开发。