Rabbit knee joint biomechanics: motion analysis and modeling of forces during hopping.

Although the rabbit hindlimb has been commonly used as an experimental animal model for studies of osteoarthritis, bone growth and fracture healing, the in vivo biomechanics of the rabbit knee joint have not been quantified. The purpose of this study was to investigate the kinematic and kinetic patterns during hopping of the adult rabbit, and to develop a model to estimate the joint contact force distribution between the tibial plateaus. Force platform data and three-dimensional motion analysis using infrared markers mounted on intracortical bone pins were combined to calculate the knee and ankle joint intersegmental forces and moments. A statically determinate model was developed to predict muscle, ligament and tibiofemoral joint contact forces during the stance phase of hopping. Variations in hindlimb kinematics permitted the identification of two landing patterns, that could be distinguished by variations in the magnitude of the external knee abduction moment. During hopping, the prevalence of an external abduction moment led to the prediction of higher joint contact forces passing through the lateral compartment as compared to the medial compartment of the knee joint. These results represent critical data on the in vivo biomechanics of the rabbit knee joint, which allow for comparisons to both other experimental animal models and the human knee, and may provide further insight into the relationships between mechanical loading, osteoarthritis, bone growth, and fracture healing.     

Development of a method for analyzing three-dimensional scapula kinematics

Background

Scapula mobility complicates upper extremity kinematics assessment. Existing methods are diverse, providing inconsistent results. The current gold standard (bone pins) is prohibitively invasive. The purposes of the current study are to describe a virtual projection alternative to surface markers for video motion capture (VMC) of the scapula and to compare the results of the projection and surface marker methods to the results of similar existing methods.

Methods

Ten participants were evaluated using VMC. Surface markers were applied to the trunk and arm in accordance with existing guidelines. Three markers were affixed to plastic base on the skin over the acromion process. Other scapular landmarks were digitized in a neutral position. These landmarks’ locations were defined in reference to the acromion cluster and used to generate the projection. Humerothoracic, glenohumeral, and scapulothoracic kinematics were evaluated during shoulder abduction, flexion, and scaption. Joint angles produced by the surface markers and the projection were compared by Bonferroni-adjusted t tests. The results were compared to prior findings in the literature.

Results

The projection resulted in greater scapulothoracic upward rotation, internal rotation, and anterior–posterior tilt and less glenohumeral elevation (p < .0055) than did surface markers. The virtual scapula produced greater estimates of scapular mobility than did surface markers, corresponding to pre-existing results from similar methodologies.

Conclusions

The result is a noninvasive measurement tool that produces different and superior results than do scapula surface markers. Measuring scapula kinematics via VMC without bone pins will facilitate future investigations into interactions between upper extremity injury, kinematics, and activity performance.     

踝关节扭伤的生物力学与运动学研究进展

踝关节扭伤是骨科临床常见病,占关节韧带扭伤的首位,如治疗不及时或不恰当,常遗留疼痛及关节不稳,继而发生骨关节炎等。目前踝关节的损伤机制、解剖学基础等已经得到了充分的研究,其诊断问题已经很明确,随着科学技术日新月异的发展,生物建模与三维有限元、三维运动捕捉系统、数字化技术的研究、体表肌电研究等技术被用于踝关节扭伤的基础研究之中,使踝关节扭伤的生物力学与运动学研究得到发挥,现结合踝关节的损伤机制等,探讨踝关节扭伤的生物力学与运动学研究进展。     

Multidirectional kinematics of the glenohumeral joint during simulated simple translation tests: impact on clinical diagnoses.

At the end ranges of motion, the glenohumeral capsule limits translation of the humeral head in multiple directions. Since the 6-degree of freedom kinematics of clinical tests are commonly utilized to diagnose shoulder injuries, the objective of this study was to determine the magnitude and repeatability of glenohumeral joint kinematics during a simulated simple anteroposterior translation test in the anterior and posterior directions. A magnetic tracking system was used to determine the kinematics of the humerus with respect to the scapula in eight cadaveric shoulders. At 60 degrees of glenohumeral abduction and 0 degrees of flexion/extension, a clinician applied anterior and posterior loads to the humerus at 0 degrees, 30 degrees, and 60 degrees of external rotation until a manual maximum (simulating a simple translation test) was achieved. Prior to each test, the reference position of the humerus shifted posteriorly 1.8+/-2.0 and 4.1+/-3.8 mm at 30 degrees and 60 degrees of external rotation, respectively. Anterior translation decreased significantly (p < 0.05) from 18.2+/-5.3 mm at 0 degrees of external rotation to 15.5+/-5.1 and 9.9+/-5.5 mm at 30 degrees and 60 degrees, respectively. However, no significant differences were detected between the posterior translations of 13.4+/-6.4, 17.1+/-5.0, and 15.8+/-6.0 mm at 0 degrees, 30 degrees, and 60 degrees of external rotation, respectively. Coupled translations (perpendicular to the direction of loading) at 0 degrees (6.1+/-4.0 and 3.8+/-2.9 mm), 30 degrees (4.7+/-2.7 and 5.9+/-3.1 mm), and 60 degrees (2.3+/-2.3 and 5.0+/-3.5 mm) of external rotation were in the inferior direction in both the anterior and posterior directions, respectively. Based on the data obtained, performing a simulated simple translation test should result in coupled inferior translations and anterior translations that are a function of external rotation. The low standard deviations demonstrate that the observed translations should be repeatable. Furthermore, capsular stretching or injury to the anterior-inferior region of the capsule should be detectable during clinical examination if excessive coupled translations exist or no posterior shift of the reference position with external rotation is noted.     

膝关节损伤的MRI诊断及其临床价值

目的：探讨MRI对膝关节损伤的诊断及临床应用价值。方法：回顾性分析266例膝关节损伤的MRI资料，男182例，女84例，年龄16～56岁，平均38岁。其中车祸损伤144例，运动损伤68例，其他54例。损伤类型，骨折31例，骨挫伤106例，软骨骨折11例，半月板损伤224例，韧带损伤198例，关节积液212例。结果：31例骨折表现为线状长T1长T2信号影；106例骨挫伤表现为斑片状等或长T1WI、等或长，T2WI信号，STIR序列呈高信号，边界不清；11例软骨骨折表现为软骨信号连续中断或凹陷，出现异常信号；224例半月板损伤表现为半月板低信号影内出现不同形状高信号灶；198例韧带损伤表现为韧带增厚、扭曲，韧带移行区有长T2信号和(或)短T1信号；212例关节积液表现为长T1长T2信号，血肿可见短T1高信号。结论：MRI对膝关节损伤的诊断具有重要的临床价值。     

新型膝关节运动分析系统的研制及临床应用

运动分析技术在临床步态分析以及肌骨系统的辅助诊断,功能评估和康复领域已有较多应用。而新型的Opti_Knee膝关节运动分析系统是一种临床操作简便,可移动便携设计,在体无创动态评估膝关节6自由度运动的分析系统,近年来也开始应用于骨科、运动医学、康复等领域。本文从技术原理和临床应用角度出发,对国内外近6年的相关文献进行了系统归纳和总结,回顾了该系统的起源与发展、结构与原理,归纳了在健康人群膝关节功能评估、膝关节运动损伤因素和膝关节疾病临床诊治方面的应用和成果,如步态特征观察、前交叉韧带损伤辅助诊断、膝骨关节炎手术疗效评价和科学指导康复等,总结了应用中遇到的问题和下一步需要攻克的难题,展望了该系统在运动损伤防治领域应用的未来。     

兔膝关节软骨单位微管吸吮黏弹性力学分析

目的 探讨体外急性消化软骨单位的生物力学特性.方法 成年8月龄新西兰白兔8只,随机分为两组,各4只.无菌条件下剖取双膝关节全层软骨,一组采用常规质量浓度0.4%的pronase酶和质量浓度0.025%的Ⅱ型胶原酶依次消化为软骨细胞;另一组采用质量浓度0.3%的dispase酶和质量浓度0.2%的Ⅱ型胶原酶联合搅拌消化3 h为软骨单位.利用微管吸吮结合半无限体细胞力学模型定量分析急性消化软骨细胞及软骨单位黏弹性力学特性,包括平衡模量(E∞)、瞬间模量(E0)和表观黏性(μ)等黏弹性参数.结果 成年软骨细胞在0.2-0.4 kPa恒定微管负压下,表现为典型黏弹性固体特征,即在微管中产生瞬间微小变形,随后发生形率单调减小的蠕变过程,其到达平衡状态时间为(110±18)s.成年软骨单位在微管吸吮负压提高到1.0～1.2 kPa时,与软骨细胞发生同样的黏弹性蠕变行为,但其瞬间吸入微管内的长度明显减少,且到达平衡状态的时间缩短为(36.5±4.5)s.同时,软骨单位黏弹性参数平衡模量(E∞)、瞬间模量(E0)和表观黏性(μ)均明显高于软骨细胞.结论 与软骨细胞相比,成年软骨单位同样表现为黏弹性固体特征,但其黏弹性力学特性明显提高.

Abstract：

Objective To characterize the biomechanical behavior and properties of the chondrons enzymatically isolated from rabbit knee articular cartilage in virto. Methods Eight months old New Zealand white rabbits were randomly divided into chondroctye and chondron groups (4 rabbits in each group). In chondrocyte groups, the full articular cartilages from both knees were enzymatically isolated to chondrocytes by 0.4% pronase and 0.025% collagenase type-Ⅱ in turn. In chondron groups, chondrons were obtained from articular cartilage using the mixture of 0.3% dispase (a neutral protease) and 0.2% collagenase type-Ⅱin at 37C for 3 h. The micropipette aspiration was used to quantify changes in biomechanical properties of chondrons and chondrocytes and the viscoelastic parameters, including K1, K2, E∞ (equilibrium modulus), E0(instantaneous modulus), and μ (apparent viscosity), were calculated coupled with standard linear half-space viscoelastic solid model. Results In response to a constant negative pressure of 0.2-0.4 kPa, the chondrocytes exhibited standard linear viscoelastic solid properties. Namely, the cells showed an initial elastic response followed by a viscoelastic creep response. then cells continued to enter into the micropipette with a monotonically decreasing rate of deformation, until reaching equilibrium within about (110±18) s. Comparing with chondrocytes, the chondrons exhibited significant viscoelasticity under a greater negative pressure of 1.0-1.2 kPa. But the instantaneous length deformed into the micropipette significantly reduced, and the equilibrium time reduced to (36.5±4.5) s. The equilibrium modulus (E∞), the instantaneous modulus (E0) and the apparent viscosity (μ) of chondrons were significantly higher than the those of chondrocytes. Conclusion Comparing with chondrocytes, the chondrons exhibited significant viscoelastic properties, and viscoelastic properties of chondrons have increased in vitro.     

膝关节半月板撕裂的磁共振表现

目的进一步认识膝关节半月板撕裂的磁共振成像(MRI)表现。方法回顾分析50例膝关节半月板撕裂的MRI资料,所有病例均经关节镜手术证实。采用永磁型MRI机,场强0.2T。结果50例半月板撕裂中,按照部位分类,半月板撕裂位于内侧半月板前角2例,内侧后角37例,外侧半月板前角5例,外侧后角3例,同时累及半月板前角、体部和后角者内侧2例,外侧1例。按照半月板撕裂的形式分为:水平撕裂8例;垂直撕裂4例;斜形撕裂26例;纵形撕裂3例;放射状撕裂4例;桶柄状撕裂2例;复杂撕裂3例。结论MRI能够清楚显示膝关节半月板撕裂的部位和形式,为临床治疗提供可靠的依据,是目前诊断半月板撕裂的最好的影像学检查方法。     

垫片改良设计对膝关节置换术后临床功能和膝关节运动的影响

目的 探讨膝关节假体垫片设计对膝关节置换术后临床功能和膝关节运动学的影响.方法 分析2007年7月至2009年6月使用GENESIS Ⅱ假体行全膝关节置换术的28例膝关节骨关节炎患者的临床资料,共42膝,平均随访27.7个月.按照使用垫片的种类分为高屈曲垫片组(男性1例,女性14例,23膝;年龄54～74岁,平均62.8岁)和标准组(男性1例,女性12例,19膝;年龄54～74岁,平均64.3岁).通过膝关节评分比较两组的临床功能.采用循环透视和软件分析的方法比较两组病例在膝关节屈伸活动时股骨后滚、伸膝装置力臂等参数,评价垫片设计对膝关节运动的影响.结果 标准组和高屈曲垫片组的术后活动度分别为120°和123°,差异无统计学意义.两组在膝关节学会评分上没有差异.高屈曲垫片组术后的Feller评分高于标准组,差异有统计学意义(P=0.012).在影像学测量上,两组病例在0～120°范围活动时股骨后滚和伸膝装置力臂的差异均无统计学意义;活动范围达到130°时,两组的伸膝装置力臂差异有统计学意义(P=0.034).结论 高屈曲垫片的改良设计在减少膝关节置换术后膝前痛的发生、改善膝关节功能方面有一定的作用;但可能会减小伸膝装置的力臂,从而影响股四头肌的做功.     

Evaluation of a method to map tibiofemoral contact points in the normal knee using MRI.

A technique using magnetic resonance imaging (MRI) is proposed for analysis of knee motion that is practical in the clinical situation. T1 weighted fast spin echo (FSE) and spoiled gradient echo (GE) sequences were compared to image both knees at 15 degrees intervals from 0 degrees to 90 degrees flexion, while unloaded and loaded. The medial and lateral tibiofemoral contact points were mapped reliably using both FSE sequences and GE sequences with intra-class correlation((2,1)) of 0.96 (CI 99%=0.94-0.97) and 0.94 (CI 99%=0.91-0.97), respectively. Results were consistent with the current literature on knee motion: the medial and lateral tibiofemoral contact pathways were different (F(1,80) = 253.9, p < 0.0001) reflecting the longitudinal rotation of the knee, the loaded and unloaded knees were not different in the healthy knee (F(1,80) = 0.007, p = 0.935), and the left and right knee were consistent for each individual (F(1,80) = 0.005, p = 0.943). Therefore, right to left differences may be attributed to pathology. MRI analysis of knee kinematics as described by this technique of tibiofemoral contact point mapping provides a robust and reliable method of recording the tibiofemoral contact pattern of the knee.     

膝后外侧角解剖学特点和力学的稳定机制

目的探讨膝后外侧角(PLC)的结构组成、解剖学和生物力学特点。方法15具30例膝关节尸体标本，解剖观察PLC的位置、组成和形态学特点。在选择性离断PLC部分结构的不同工况下。观察膝内翻加载移位和胫骨上端的后外侧旋转加载移位。结果(1)PLC位于膝关节后外侧区域，邻近上胫腓联合处，由膝外侧副韧带、豆腓韧带、弓状韧带、腘肌腱、腘腓韧带、后外侧关节囊等结构组成。(2)PLC切断后，膝内翻移位增加274％～280％，胫骨上端后外侧旋转移位增大210％～305％。其中膝外侧副韧带离断后膝内翻移位增加比例达78％～87％；而离断腘腓韧带后胫骨上端后外侧旋转移位增幅比例达81％～91％。结论(1)膝外侧副韧带和腘腓韧带是膝后外侧角中主要的稳定结构；(2)膝后外侧角具有明显对抗膝内翻不稳和膝后外侧旋转不稳定的作用。     

MRI在膝关节损伤诊断中的临床价值

目的　探讨MRI对于膝关节损伤的临床应用价值。方法　回顾性分析 56例膝关节损伤的MRI资料。结果　韧带损伤48例 ,MRI表现为扁平条带状低信号影增粗 ,边缘模糊或呈波浪状 ,T1 WI 呈低或高低混杂信号 ,T1 WI 呈高信号。半月板损伤 40例 ,表现为三角形低信号影内出现不同形状高信号灶。骨挫伤 1 8例 ,表现为T1 WI 呈低信号或高低混杂信号 ,T2 WI 呈高信号。软骨骨折 8例 ,表现为软骨断续或凹陷 ,软骨层内见短T1 长T2 信号。结论　MRI对于膝关节损伤的诊断具有重要的临床价植     

健康青年人的膝关节软骨厚度3.0T MRI的定量研究

目的:探讨3.0T MRI精确测量健康青年膝关节软骨厚度为骨关节炎的定量诊断和关节置换精准截骨提供可靠的解剖参数。方法:自2013年1月至2013年12月于吉林省长春地区招募30名健康青年志愿者,男14名,女16名,年龄22~33(25.8±2.4)岁。对每名志愿者的双膝关节进行3.0 T MRI扫描,对股骨外侧髁(lateralis femoris condylus,LFC)、股骨内侧髁(medialis femorisc ondylus,MFC)、胫骨外侧平台(lateral tibial plateau,LTP)、胫骨内侧平台(medial tibial plateau,MTP)进行软骨厚度测量。结果:在LFC、MFC、LTP、MTP 4个区域中,无论青年男性或女性,左、右侧膝关节软骨厚度比较,差异均无统计学意义(P>0.05);健康青年男性与女性之间膝关节软骨厚度比较,差异有统计学意义(P<0.05)。在同一性别组,LFC软骨厚度中间较薄,前、后方较厚;MFC软骨厚度前方最薄,从前方向后方逐渐增厚;LTP软骨厚度中间最厚,后方次之,前方最薄;MTP软骨厚度前方最薄,中间、后方相对均匀且均较前方厚。结论:在我国22~33岁正常健康青年人中,性别差异可能是膝关节各个区域软骨厚度差异的重要因素。无论男性或女性健康青年人,整个膝关节软骨厚度分布不均匀,但左、右侧膝关节相同区域软骨厚度无明显差异。     

膝关节外侧半月板假撕裂MRI征象分析及临床意义

目的:明确板股韧带及膝横韧带所致外侧半月板假撕裂的发生机制,探讨外侧半月板假撕裂与真撕裂的鉴别方法。方法:对自2012年6月至2014年2月间72例(左膝44例,右膝28例)经关节镜证实的无外侧半月板撕裂的膝关节进行矢状及冠状位MR扫描,其中男41例,女31例;年龄25～61岁,平均33.7岁。观察板股韧带及膝横韧带的MRI表现。结果:膝横韧带与外侧半月板前角及其中央腱性附着部之间以脂肪组织分隔,在MRI矢状像上,可见脂肪组织在膝横韧带与外侧半月板前角之间形成的线样稍高信号裂隙,类似外侧半月板前角撕裂,称为外侧半月板前角假撕裂。板股韧带在矢状像上表现为位于后交叉韧带前或后方的类圆形或短棒状低信号结构,而在冠状像上表现为自外侧半月板后角至股骨内侧髁外侧面的条带样低信号结构。在矢状像上,板股韧带与外侧半月板后角之间显示出一线样高信号,称为外侧半月板后角假撕裂。膝横韧带在MRI上的出现率约34.7%(25/72),表现为外侧半月板前角假撕裂18例,均表现为外侧半月板形态规则、撕裂线斜行,矢状位图像可连续显示膝横韧带,冠状位图像能显示该韧带的长轴。板股韧带显示率为73.6%(53/72),其中板股前韧带为23.6%(17/72),板股后韧带为70.8%(51/72),两条韧带同时存在为16.7%(12/72).表现为外侧半月板后角假撕裂25例,假撕裂仅有两种走行方向,即后下斜行(19/25)或垂直方向(6/25).结论:根据外侧半月板形状、撕裂线方向、观察矢状和冠状位图像,可正确区分外侧半月板的真、假撕裂。     

单髁膝关节置换术后膝关节三维运动学特性研究

目的探讨单髁膝关节置换后膝关节与骨关节炎病变膝关节及正常膝关节在正常平地行走中的三维运动学差异。方法在瑞金医院骨科2011年3月至2012年5月间进行的7例单髁膝关节置换手术病例和10位健康人对照组进行步态分析比较。7例单髁病例中,男1例,女6例,平均年龄65．3岁（53～73岁）,步态分析时间距手术后平均7个月（4～12个月）,所有单髁膝关节置换均使用Oxford（BiometLtd）活动平台内侧单髁膝关节假体,手术病例对侧膝关节也存在内侧间隙骨关节炎并等待进行手术。10例健康人中,男5例,女5例,平均年龄56．8岁（53～6l岁）,所有健康人对照组均无髋膝关节疼痛和髋膝关节活动功能障碍病史。本研究采用红外运动捕捉系统（MX．F40,Vicon,OxfordUK）,对多点体表标记点进行步态数据记录,计算股骨相对于胫骨的旋转和移动运动学数据,比较单髁膝关节置换后膝关节在上述三维运动中与对侧病变膝关节和正常膝关节的差异。结果在步态周期内,单髁膝关节置换术后膝关节三维运动学表现与对侧病变膝关节及正常对照组膝关节均存在不同的差异。其中,在矢状面屈伸运动、水平面的内外旋运动、冠状面内外翻运动以及前后方向平移运动中,单髁置换后膝关节运动曲线都与正常膝关节更为接近。结论单髁膝关节置换术后,膝关节运动学表现上比对侧病变膝关节在旋转运动和平移运动中,更接近与正常膝关节的运动学特性。     

膝关节韧带损伤的MRI诊断

目的:分析膝关节韧带损伤的MRI表现及应用价值。方法:85例膝关节损伤患者,男56例,女29例,年龄14⁷0岁,平均39岁,均经手术或关节镜检查明确诊断,对所有患者的MRI进行回顾性分析。结果:MRI显示侧副韧带损伤77条、交叉韧带损伤81条。侧副韧带损伤分为轻、中、重度;交叉韧带损伤表现为不完全撕裂、完全撕裂及撕脱骨折。MRI可显示侧副韧带及交叉韧带局灶或弥漫性肿胀、韧带连续性中断,断端移位及韧带信号改变,可显示韧带撕脱骨折及移位,经与手术或关节镜对照分析,磁共振诊断内侧副韧带、外侧副韧带、前交叉韧带及后交叉韧带准确性分别为92·3%、97%、81·3%、100%。结论:膝关节磁共振检查对韧带损伤的程度、类型的诊断较为准确,对临床治疗指导价值较大。     

膝关节韧带损伤的MRI诊断

目的:分析膝关节韧带损伤的MRI表现及应用价值。方法:85例膝关节损伤患者,男56例,女29例,年龄14~70岁,平均39岁,均经手术或关节镜检查明确诊断,对所有患者的MRI进行回顾性分析。结果:MRI显示侧副韧带损伤77条、交叉韧带损伤81条。侧副韧带损伤分为轻、中、重度;交叉韧带损伤表现为不完全撕裂、完全撕裂及撕脱骨折。MRI可显示侧副韧带及交叉韧带局灶或弥漫性肿胀、韧带连续性中断,断端移位及韧带信号改变,可显示韧带撕脱骨折及移位,经与手术或关节镜对照分析,磁共振诊断内侧副韧带、外侧副韧带、前交叉韧带及后交叉韧带准确性分别为92·3%、97%、81·3%、100%。结论:膝关节磁共振检查对韧带损伤的程度、类型的诊断较为准确,对临床治疗指导价值较大。     

Ligament tension pattern in the flexed knee in combined passive anterior translation and axial rotation.

Twenty-two fresh-frozen specimens were used to measure tensions generated in selected bands of the major ligaments of the flexed knee (40-90 degrees) when an axially prerotated tibia is subjected to passive anterior shear and when an anteriorly pretranslated tibia is subjected to passive axial torque. The tensions were measured using the buckle transducer attached to the anteromedial band of the anterior cruciate ligament [ACL (am)], the posterior fibers of the posterior cruciate ligament [PCL (pf)], the long fibers of the medial collateral ligament [MCL (lf)], and in the total lateral collateral ligament [LCL]. The knee specimens were subjected to the combined motions in a 6-df passive loading apparatus. The results indicated that the joint resistance to anterior translation increased markedly with internal prerotation and only marginally with external prerotation. This increase in joint resistance, however, was associated with a decrease in ACL function. It has been inferred that the posterior structures, capsular and meniscal, contribute significantly to joint resistance when the tibia is prerotated in either sense. For internal prerotation, the interference between the medial femoral condyle and the central tibial eminence was found to be an additional mechanism of resistance to anterior translation. Also, it has been found that although the ACL (am) tension increased with internal rotation in the normal case, it decreased with internal rotation in the presence of an anterior pretranslation. It is concluded that ACL response to combined joint motion cannot be ascertained by a simple summation of its responses to individual motions.     

The axes of rotation of the thumb carpometacarpal joint.

Two axes of rotation of the carpometacarpal (CMC) joint of seven cadaver thumbs were located using an axis finder. The flexion-extension axis is located in the trapezium and the abduction-adduction axis is in the first metacarpal. These axes are fixed, are not perpendicular to each other or to the bones, and do not intersect. Motion of the first metacarpal on the trapezium can be defined by these two axes. Understanding of the movements of the basal joint of the thumb is essential to the study of its function and reconstruction.