非预期条件下前交叉韧带重建术后运动员侧切动作下肢运动生物力学特征

目的 量化非预期条件下前交叉韧带重建(anterior cruciate ligament reconstruction, ACLR)术后运动员侧切动作中膝关节生物力学特征,探讨运动员前交叉韧带(anterior cruciate ligament, ACL)损伤潜在风险。 方法 应用红外运动捕捉系统和三维测力台同步采集 30 名 ACLR 男性运动员在预期和非预期条件下侧切动作中健侧、患侧下肢运动学和动力学数据。 应用双因素方差分析对关节角度、关节力矩、地面反作用力( ground reaction force, GRF)等测试指标进行统计分析。 结果 患侧肢体的膝关节屈曲角度、外翻力矩和屈曲力矩显著低于健侧肢体,内旋力矩和胫骨前剪切力显著高于健侧肢体。 与预期条件相比,非预期条件下膝关节屈曲角度、内旋力矩、胫骨前剪切力显著增加。 患侧肢体膝关节外旋角度在预期和非预期条件下均显著高于健侧,非预期条件下健侧肢体侧向 GRF 和前后 GRF 显著小于预期条件,患侧肢体侧向 GRF 显著高于预期条件。 结论 ACLR 运动员进行侧切动作时,相比于健侧,患侧表现出较小的膝关节屈曲角度,较大的膝关节内旋力矩和胫骨前剪切力的生物力学特征,可能存在较大的 ACL 潜在损伤风险;在非预期条件下,ACLR 运动员双侧下肢均表现出膝关节内旋力矩增大,侧向 GRF 增大和胫骨前剪切力增大的生物力学特征,提示 ACL 潜在损伤风险不仅限于患侧,健侧下肢也应加强侧切动作中 ACL 损伤预防。     

股骨内翻和胫骨内翻的运动学和足底压力分析

目的 探究胫骨侧和股骨侧来源的两种单侧膝骨关节炎膝内翻在步态分析中的运动学参数和足底压力差异,为不同类型膝内翻提供生物力学理论基础。方法 招募26名单侧膝骨关节炎型膝内翻患者,股骨侧和胫骨侧来源各13名受试者。利用Noraxon MyoMotion三维动作捕捉系统和Footscan平板式足底压力测试系统,测量受试者在自然行走状态下的步态,采集受试者步态的时空指标、下肢各关节运动学参数、足底压力,并进行两组间对比分析。结果 胫骨侧膝内翻的膝关节屈伸范围、髋关节外展峰值、髋关节内收外展活动范围、踝关节内旋峰值均大于股骨侧膝内翻,而膝关节屈曲峰值、髋关节内收峰值小于股骨侧膝内翻;与股骨侧膝内翻相比,胫骨侧膝内翻受试者第4、5跖骨足底受力时间、压力峰值都增加(P<0.05)。在第3跖骨区域中,股骨健侧肢体比胫骨畸形健侧肢体的冲量更大;而在足跟内侧区域,股骨健侧肢体的冲量更小(P<0.05)。结论 两种不同类型单侧膝内翻患者在运动学参数和足底压力方面存在一定差异。研究结果有助于正确认识膝内翻引起的异常步态,为不同类型膝内翻诊治、术后康复和肢体锻炼提供可靠参考。     

女性全身关节过度活动患者跳深着陆时膝关节应力分析

目的 分析全身关节过度活动(generalized joint hypermobility, GJH)女性患者与健康女性在跳深着陆中膝关节软骨、半月板von Mises应力分布差异。方法 采集女性GJH患者与女性健康受试者在跳深着陆缓冲阶段垂直地面反作用力(vertical ground reaction force, VGRF)峰值时刻的膝关节运动学与地面反作用力特征,通过逆动力学计算膝关节反作用力,并将膝关节沿股骨长轴方向的合力作为载荷;基于1名女性膝关节三维有限元模型,分别对2组受试者跳深着陆过程进行数值仿真,计算膝关节软骨与半月板von Mises应力及应力分布。结果 在跳深着陆VGRF峰值时刻,GJH组和对照组膝关节屈曲、外翻角度具有统计学意义(P<0.05)。相比于对照组,GJH组膝关节屈曲角度降低、外翻角度增加;在跳深着陆中,GJH组膝关节内部承受应力更大且胫股关节内、外侧室负重区应力分布不均衡,其股骨软骨外侧髁外侧、外侧胫骨软骨前部/中部外侧以及外侧半月板前角、体部外侧缘为应力集中部位。结论 女性GJH患者因膝关节活动范围增大、关节囊松弛,导致在跳跃类项目中膝关节...     

膝关节矢状面机构模型

建立矢状面上膝关节二维机构模型，求解矢状面髌股关节求解屈膝过程中髌骨与股骨的接触点移动，髌骨倾角、髌韧带倾角变化，髌股关节功能角变化以及髌股接触力和髌韧带作用力的变化等髌股关节运动及动力学参数．依据膝关节主要组成部分的功能及相互间连接关系，以股胫关节交叉四连杆模型为基础，通过对髌股关节的几何描述及力平衡限定，并运用ADAMS软件进行分析计算，计算结果与文献实验结果吻合良好。     

人体膝关节平地行走时的动力学模拟

基于美国BRG公司的运动及动力学仿真分析软件LifeMOD,建立包括股骨、胫骨、腓骨、4条主要韧带及肌肉在内的较完整的膝关节动力学模型,并用该模型模拟了人体下肢在平地行走时膝关节的动力学行为以及前交叉韧带缺损对膝关节接触力大小的影响。通过动力学分析,得到人体在平地行走时,胫股关节之间最大的接触力值为2645N,最大韧带张力为590N,发生在内侧副韧带上;当胫股关节之间的滑动受到限制时,最大的韧带张力发生在前交叉韧带上,为560N,研究结果与文献较接近。通过动力学模拟,可以得出结论：胫股关节之间的滑动对韧带张力有较大影响;前交叉韧带缺损使得胫股关节之间的接触力变小。     

预期条件下不同侧切角度膝关节应力状态的有限元分析

目的 探讨预期条件下不同角度侧切触地过程中膝关节运动学、地面反作用力（ground reaction force, GRF）特征以及软骨、半月板的应力状态。方法 采集14名受试者在预期条件下分别进行45°、90°和135°侧切时的运动学和GRF数据，通过Visual 3D逆动力学计算获取膝关节反作用力，基于膝关节三维有限元模型分别对3种侧切角度下触地过程进行数值仿真。结果 预期条件下3种侧切角度在触地过程中的膝关节运动学特征存在显著性差异（P＜0.001），膝关节屈曲程度随侧切角增大而增加；垂直GRF随侧切角增加而显著减小（P＜0.001），水平GRF呈现出相反的趋势；3种侧切角度下，90°侧切时髌骨软骨以及股骨软骨接触应力峰值较大, 前交叉韧带（anterior cruciate ligament，ACL）接触点主应力峰值较大，其次为135°和45°侧切；3种侧切角度下，外侧股骨软骨接触应力峰值均大于内侧。结论 90°侧切运动时膝关节损伤风险更大，135°侧切时膝关节内部的应力状态与90°侧切相比较为良好。预期条件下膝关节损伤风险并不随侧切角增大而升高。     

外置式人工关节控制下的家兔膝关节再生与功能恢复

目的 探讨仿生运动生物力学环境下关节再生的可能性。方法 采用实验家兔7只,在实验家兔一侧股骨干和胫骨骨干各穿2枚直径1.5 mm 克氏针,分别安装框架平台。然后在体外通过在膝关节内、外侧分别安装模拟膝关节矢状面运动轨迹的平面四杆机构,连接股骨和胫骨上已经安装好的框架平台。在股骨髁和胫骨平台同时截骨去除关节软骨、部分软骨下骨及十字交叉韧带和半月板等结构,但不损伤肌腱起止点,保留关节囊及囊外韧带,保留髌骨和籽骨。术后家兔自然活动。在关节截骨后的愈合过程中定期拍摄X线片,测量关节矢状面的活动度和骨性间隙。结果 7只实验家兔中6例成功安装外置式人工关节,截骨微创骨穿针仿生运动外置式人工关节控制下自然活动。膝关节被动活动范围分别为：术后第1周,极限屈曲位（144.7±15.62）°, 极限伸直位（44.2±25.77）°, 活动度（100.5±29.03）°; 术后第12周,极限屈曲位（139.4 ± 12.92）°, 极限伸直位（40.4±22.04）°,活动度（99.0±23.39）°。截骨术后第12周与截骨术后第1周相比,屈曲位、伸直位和活动度均没有显著差异。X线显示骨性关节间隙依然存在。截骨侧骨性关节间隙明显减小,由截骨术后第1周（4.03±1.84） mm 减小到第12周（2.32±1.05） mm,而对侧正常骨性关节间隙为（1.27±0.22） mm。术后16周拆除外置式人工关节,切开关节囊观察,发现新生白色软骨覆盖截骨再生表面,表面光滑,具有典型关节滑车结构,并且观察到类似韧带的纤维束从再生的股骨下端发出,终止于新生的胫骨上端。术后第25周,所有6只实验家兔截骨再生膝关节屈曲位（148.3±4.75）°,伸直位（48.30±17.57）°,活动范围（100.0±20.80）°;对侧（左侧）正常膝关节屈曲位（148.3±7.5）°,伸直位（21.6±9.09）°,活动范围（126.7±6.88）°。截骨侧、对侧骨性关节间隙分别为（1.4±0.59）、（0.92±0.35） mm。结论 外置式仿生运动人工关节为家兔膝关节再生保留了再生空间,提供了一种运动模拟环境、印证了骨折愈合过程的应力适应性。本研究结果提示仿生运动生物力学环境下,正常家兔膝关节内截骨后再生是可能的。     

髌股关节不稳相关解剖结构的MRI分析

目的：探讨影响髌股关节不稳的主要解剖因素。方法回顾性分析2010年9月—2012年9月中山大学附属第三医院关节外科诊治的髌股关节不稳20例患者患侧膝关节MRI资料,并将其纳入髌股关节不稳组,其中男8例,女12例,年龄(24±8)岁;包括髌骨脱位、髌骨内侧支持带损伤等导致的髌股关节不稳,排除伴有膝关节多发韧带损伤、膝关节周围骨折、关节大量积液以及曾经进行膝关节手术的病例。选取同期诊断为髌股关节排列正常69例患者的MRI资料作为正常对照组,其中男31例,女38例,年龄(25±5)岁;排除伴有明显髌股关节不适症状、膝关节可疑骨折以及交叉韧带损伤的病例。测量两组MRI的髌骨高度、股骨滑车沟角、股骨滑车外侧面比例以及胫骨结节-滑车沟间距的数值,分别进行独立样本t检验,logistic回归分析其相关性。结果正常对照组和髌股关节不稳组的髌骨高度、股骨滑车外侧面比例、股骨滑车沟角、胫骨结节-滑车沟间距分别为1.02±0.15、0.63±0.13、145°±8°、(1.15±0.24) cm 和1.16±0.14、0.44±0.13、152°±8°、(1.69±0.27)cm,两组间各指标差异均有统计学意义(t 值分别为3.728、5.755、3.446、8.614,P 值均<0.01)。 Logistic回归分析显示,股骨滑车外侧面比例减少、股骨滑车沟角增大以及胫骨结节-滑车沟间距增大与髌股关节不稳的发病之间的相关性有统计学意义(P<0.05)。股骨滑车外侧面比例、胫骨结节-滑车沟间距以及股骨滑车沟角的标准偏回归系数为分别为-78.221、0.277和0.026。结论髌股关节不稳患者表现为髌骨高位、股骨滑车沟角增大、股骨滑车外侧面比例减少以及胫骨结节-滑车沟间距增大,其中胫骨结节-滑车沟间距增大以及股骨滑车外侧面比例减少是髌股关节不稳发病的主要因素。     

骑行时不同屈曲角度膝关节软骨受力分析

在对骑行人车系统动力学研究的基础上,分析在骑行周期内膝关节软骨的受力状态,以期获得关节软骨受力的规律,增加对骑行时膝关节生物力学特性的理解。基于有限元分析法,建立包括股骨、胫骨、腓骨、髌骨、关节软骨、半月板及韧带组织的人体全膝关节有限元模型。将骨组织刚体化,并对其施加屈曲位移边界条件,包括胫骨相对股骨的内旋、内收、前移和外移以及髌骨相对股骨的屈曲、内旋、内倾以及外移。通过显式动力学分析计算,获得膝关节屈曲60°、80°和100°相位,同时得到骑行状态上述屈曲位处膝关节软骨的应力分布。结果 通过有限元分析,获得骑行姿态下膝关节相关相位的力学分布规律。结果表明,相同载荷下,最大von-Mises应力出现在屈曲100°位置,股骨软骨应力增幅达71.25%,髌骨软骨增大29.36%;随着骑行屈曲角度的增加,胫股关节高应力区逐渐向膝关节后部转移,髌股关节软骨受力逐渐上移。骑行时高应力发生在膝关节屈曲角度较大位置,胫骨平台软骨后侧、髌骨软骨上侧承受更大应力。     

胫骨旋转对髌股关节应力分布的影响

目的探明胫骨旋转状态对髌股关节应力分布的影响。方法选取7个新鲜离体膝关节,在屈膝30°、60°、90°状态下,分别用压敏片测量胫骨中立位、内旋10°、20°、30°和外旋10°、20°、30°时的内、外侧髌股关节接触压力与峰值。结果外旋过程中,外侧髌股关节的接触压均值和接触压峰值呈非线性递增趋势,内侧呈非线性递减趋势;内旋过程中,外侧髌股关节的接触压均值和峰值逐渐减小,内侧则增加显著。上述变化在内旋20°到外旋20°的范围内较有规律。结论胫骨旋转畸形使髌股关节应力分布严重失衡,可能是引起髌股关节退变的重要因素。     

Association of knee flexion angle after posterior-stabilized total knee arthroplasty with postoperative tibial external position relative to the femur and the extent of tibial internal rotation from knee extension to flexion

BackgroundThis study evaluated the relationship between preoperative and postoperative knee kinematics, moreover, investigated tibial rotational position and the extent of tibial internal rotation from knee extension to flexion as factors to obtain significant knee flexion after total knee arthroplasty (TKA).MethodsFifty-four patients (60 knees total; 15 males, 16 knees; 39 females, 44 knees) who underwent posterior-stabilized TKA using a navigation system were included. Intraoperative knee kinematics involving tibial rotational position relative to the femur and the extent of tibial internal rotation were examined at two time points: 1) after landmarks registration (pre-TKA) and 2) after skin closure (post-TKA). The relationship between the knee flexion angle at one year postoperatively and intraoperative tibial rotational position, or the extent of tibial rotation among several knee flexion angles calculated with a navigation system were investigated.ResultsThe postoperative knee flexion angle was positively associated with the preoperative flexion angle and intraoperative knee kinematics at post-TKA involving tibial external position relative to the femur at knee extension and the extent of tibial internal rotation from extension to 90° of flexion or to maximum flexion. There was a positive relationship between the extent of tibial internal rotation at pre-TKA and that at post-TKA.ConclusionsThe intraoperative kinematics of the extent of tibial internal rotation at post-TKA was influenced by that at pre-TKA. The greater external position of the tibia relative to the femur at knee extension and the greater extent of tibial internal rotation at post-TKA might lead to good knee flexion angle.     

Magnetic resonance imaging study of alteration of tibiofemoral joint articulation after posterior cruciate ligament injury

Cadaveric studies have shown that the posterior cruciate ligament (PCL) is an important constraint to posterior translation of the tibia. Arthroscopic studies have shown that chronic PCL injuries predispose to articular cartilage lesions in the medial compartment and the patellofemoral joint. The aim of the present study was to investigate sagittal plane articulation of the tibiofemoral joint of subjects with an isolated PCL injury.Magnetic resonance was used to generate sagittal images of 10 healthy knees and 10 knees with isolated PCL injuries. The subjects performed a supine leg press against a 150 N load. Images were generated at 15° intervals as the knee flexed from 0 to 90°. The tibiofemoral contact and the flexion facet centre (FFC) were measured from the posterior tibial cortex.The contact pattern and FFC was significantly more anterior in the injured knee from 45 to 90° of knee flexion in the medial compartment compared to the healthy knee. The greatest difference between the mean TFC points of both groups occurred at 75 and 90°, the difference being 4 mm and 5 mm respectively. The greatest difference between the mean FFC of both groups occurred at 75° of flexion, which was 3 mm. There was no significant difference in the contact pattern and FFC between the injured and healthy knees in the lateral compartment.Our findings show that there is a significant difference in the medial compartment sagittal plane articulation of the tibiofemoral joint in subjects with an isolated PCL injury.     

Preoperative tibiofemoral rotational alignment is a risk factor for component rotational mismatch in total knee arthroplasty

BackgroundRotational mismatch between the femoral and tibial components is reported to be a risk factor for unsuccessful total knee arthroplasty (TKA). However, the rotational mismatch can still occur even when each component is aligned within the desired angle. Therefore, there may be other unknown factors. This study aims to investigate a risk factor for component rotational mismatch in TKA. The authors hypothesized a significant correlation between the rotational mismatch angle and not only the rotational alignments of components, but also the preoperative tibiofemoral rotation angle.MethodThis retrospective cohort study included 79 knees who underwent TKA. Computed tomography images were obtained preoperatively and 2 weeks after surgery for the component positional measurement. The postoperative component rotational mismatch angle between the tibial and femoral components and the rotational alignment of each tibial and femoral component to anatomical axes was evaluated. In addition, the preoperative rotational angle between the tibia and femur bones and patients’ demographics were also investigated. The correlation between the postoperative component rotational mismatch angle and perioperative variables was analyzed to identify risk factors for component rotational mismatch.ResultsThe mean component rotational mismatch angle was 1.8° of internal rotation of the tibial component relative to the femoral component, and the angle ranged from 11.3° of internal rotation to 7.3° of external rotation of the tibial component. Multivariate regression analysis showed that the preoperative rotational alignment between the tibia and femur and the rotational alignment of each component were influential factors in the postoperative component rotational mismatch angle.ConclusionThe preoperative tibiofemoral rotational alignment and the rotational alignment of each tibial and femoral component and are risk factors for the postoperative component rotational mismatch in TKA.     

单髁置换术应用于骨关节炎合并前交叉韧带缺失的三维有限元研究

目的采用有限元方法比较前交叉韧带(anterior cruciate ligament,ACL)完整与缺失的骨关节炎患者单髁关节置换(unicompartmental knee arthroplasty,UKA)术后膝关节生物力学特性,分析ACL缺失对膝关节单髁置换术后的运动和应力的影响。方法根据膝关节CT、MRI图像,建立有限元模型。采用逆向工程技术重建活动衬垫单髁假体,加载入该正常膝关节三维有限元模型。在不同屈膝角度(0°、30°、60°、90°、120°)加载载荷,观察在ACL完整(ACL-intact,ACLI)和缺失(ACL-deficiency,ACLD)情况下,膝关节的最大接触压和位移程度。结果 UKA-ACLI与UKA-ACLD模型在膝关节屈膝各角度,各部位(外侧股骨软骨、胫骨软骨、半月板、股骨假体、胫骨假体、衬垫)最大应力无明显差异,ACLD模型在膝关节屈膝0°和30°位前后位移明显大于ACLI模型,在膝关节屈膝0°位股骨相对内旋减小,在膝关节屈膝30°位股骨相对外旋增加。结论标准位置假体植入情况下,ACL缺失并不会导致UKA术后应力异常增大,会导致在膝关节伸直位时位移增加。     

膝关节单髁置换术胫骨假体不同后倾角对假体磨损和功能的影响

目的 建立单髁置换术胫骨假体后倾3°和7°膝关节不同屈膝角度三维有限元模型,研究两种后倾角膝关节生物力学特性和假体磨损及其对功能的影响.方法 结合人体膝关节CT与MRI图像和第3代Oxford假体,建立胫骨假体后倾3°和7°下屈膝单髁置换术有限元模型,在股骨内外侧髁中心点上施加1 kN载荷模拟人体站立相负重,分析不同屈...     

膝屈曲状态胫股关节压应力光弹性分析

以胫股关节光弹材料模型模拟膝关节在屈曲０°、１０°、２０°和３０°状态下加载。结果显示胫股间接触面积内髁大于外髁，应力分布外髁大于内髁，最大应力分布于接触部位中心点附近。随着膝关节屈曲角度增加，（１）中心点后移，３０°以内胫股间打滑率内侧为４０．２３％，外侧为４５．９２％；（２）胫骨平台两中心点内移，中心点间距增加；（３）胫股间接触面积减少；（４）应力峰值增加，其增加率远大于面积减少率。实验结果提示膝关节畸形矫正时，要注意恢复胫股间的正常对合与应力分布。     

Movement and volume of infrapatellar fat pad and knee kinematics during quasi-static knee extension at 30 and 0° flexion in young healthy individuals

IntroductionThe purpose of this study was to determine the changes in the shape and volume of the infrapatellar fat pad (IPFP) associated with knee flexion angle in young healthy individuals.MethodsYoung, healthy individuals without a history of knee injuries participated in this cross-sectional study. Behavior of the IPFP was quantified using three-dimensional (3D) models of the IPFP, patella, patellar tendon, femur, and tibia obtained from MRI taken at 0° and 30° flexion. The outcomes were movement and volume change of the IPFP, movement of the patella and the tibia, and change of the patellar tendon angle and length.ResultsThe anterior surface of the IPFP significantly moved anteriorly by 5.23 mm (p = .003) between 30° and 0°. Change in the volume of the IPFP was significantly increased or decreased in eight hyperoctants defined by the tibial coordinate system. The IPFP moved from the postero-supero hyperoctants to anterior hyperoctants. Significant correlations were observed between the IPFP and mobility of the patella, patellar tendon or tibia.ConclusionThe IPFP moves antero-inferiorly during quasi-static knee extension from 30 to 0° in young healthy individuals. Comparisons of IPFP behavior between the healthy and pathological knees may help us understand the role of IPFP and problems caused by IPFP contracture in future studies.     

Squatting,lunging and kneeling provided similar kinematic profiles in healthy knees—A systematic review and meta-analysis of the literature on deep knee flexion kinematics

Background

Understanding healthy deep flexion kinematics will inform the design of conservative clinical rehabilitation strategies for knee osteoarthritis and contribute to improved knee prosthesis design. This study is a systematic review and meta-analysis of the kinematic outcomes measured at the healthy tibiofemoral joint during loaded deep knee flexion.

Tibial displacement and rotation during seated knee extension and wall squatting: A comparative study of tibiofemoral kinematics between chronic unilateral anterior cruciate ligament deficient and healthy knees

BackgroundFollowing anterior cruciate ligament (ACL) rupture, the knee becomes unstable with alterations in joint kinematics including anterior tibial displacement (ATD), and internal tibial rotation. Therapeutic exercises that promote faulty kinematics should be discouraged, especially early post-reconstruction, to avoid graft stretching and possibly longer-term osteoarthritis. Our study aimed to compare ATD and tibial rotation during two commonly prescribed exercises, namely: open kinetic chain (OKC) seated extension and closed kinetic chain (CKC) single leg wall squatting in ACL-deficient and healthy knees.MethodsEight ACL-deficient patients and eight healthy subjects matched for age, gender and sports history were assessed using Qualisys 3D-Motion Analysis System to track 17 infrared markers while performing a seated knee extension with 3 kg weight and a unilateral wall squat. We developed a model to measure joint kinematics through 70° of knee flexion and extension. ANOVA and paired t-tests compared relative ATD and tibial rotation between exercises and groups at 10° increments of flexion and extension.ResultsWe found increased ATD in the wall squat compared to the seated extension (p = 0.049). There was no difference in ATD between the healthy and ACL-deficient knees but overall the tibia was significantly more internally rotated (p = 0.003) in ACL-deficient knees, irrespective of the exercise, possibly interfering with the screw-home mechanism.ConclusionsCKC exercises, in particular wall squats, are not necessarily safer for patients with ACL-deficiency and possibly ACL-reconstruction; although generalization should only be made with appropriate caution. Clinicians require a detailed knowledge of the effect of exercise on knee joint kinematics.