正常膝关节和人工膝关节髌股关节高屈曲运动特性及其比较分析

目的　分析人体正常膝关节和人工膝关节高屈曲活动下髌股关节的运动, 为膝关节髌股关节运动特性研究提供参考。 方法　建立包括膝关节骨组织和主要软组织在内的正常膝关节以及人工膝关节的动态有限元模型,采用三束股四头肌肌力非同步变力加载的方式,对膝关节下蹲运动中髌股关节的运动特性进行研究,并与相关研究结果进行对比分析。 结果　通过有限元分析,获得高屈曲膝关节三维运动的相对运动参数。髌股关节在位移和旋转均呈现出相同的运动趋势,同时,存在局部的差异,在低屈曲时, 人工髌股关节表现出先外倾后内倾的运动趋势,而正常髌股关节表现出持续内倾的运动特性。 结论　通过仿真和对比分析,人体髌股关节的运动数据总体趋势近似,同时存在差异。 对于正常膝关节,差异的原因主要在于髌骨运动各个方向上和不同屈曲度时的约束程度的改变;对于人工膝关节,差异主要来源于膝关节型面和结构的改变,以及坐标系定义、在体和离体差异、负荷加载差异。     

人体膝关节动态有限元模型及其在TKR中的应用

目的 研究膝关节高屈曲活动下运动和应力等的动态特征。为膝关节生物摩擦学研究提供相对运动和应力分布等生物力学数据 方法 建立包括人体主要骨与软组织的全膝关节置换前后的膝关节的动态有限元模型,对天然及全膝置换后膝关节下蹲运动和接触应力分布进行分析,并与相应的尸体实验的结果进行验证分析。结果 通过有限元分析,获得高屈曲膝关节的三维相对运动参数,胫股关节和髌股关节的接触位置和应力等动态力学参数。有限元分析结果表明,分别在膝关节过伸和高屈曲时,在胫骨高分子聚乙烯平台的胫骨平台轮柱和平台前部的交界处、胫骨平台内后方和轮柱后部三个区域发生较高的接触应力。这些也正是假体发生较高磨损率的区域 结论 所建立的有限元模型能够对于膝关节下蹲动作的运动、接触等力学行为进行评估,为临床膝关节全膝置换术、膝关节假体的摩擦学研究及其膝关节假体设计提供有力的分析工具。     

利用2D-3D自动注册技术研究TKA术后胫股关节运动

目的重建全膝置换(total knee arthroplasty,TKA)膝关节三维运动,研究后稳定型假体之间的运动和接触。方法以16例TKA膝关节为研究对象,获取动态X线透视图像和假体三维模型,建立2D-3D自动注册算法,重建膝关节的三维运动,计算运动学参数并测量假体之间的接触位置。结果单幅X线图像注册时间小于30 s,图像平面内重复性注册精度为0.4 mm和0.5°。高屈曲垫片对膝关节屈曲度和胫骨内外旋无明显改进。股骨假体在胫骨垫片的外侧接触点后移范围大于内侧。稳定柱后方的接触发生在屈膝约30°以后,平均接触范围小于9 mm。结论 2D-3D自动注册技术在精度和效率上达到TKA膝关节在体三维运动测量要求,测量结果对TKA膝关节生物力学研究和改进假体设计具有参考意义。     

基于MRI的全膝有限元模型建立与前交叉韧带重建术模拟方案

目的建立完整的人体膝关节三维有限元模型,并在此基础上建立了用于前交叉韧带重建模拟的胫股骨隧道和人工韧带模型,为进一步分析打下基础。方法以MRI图像作为数据源,运用逆向工程软件Geomagic及有限元分析软件ANSYS9.0,参考大量有关实验测试数据的文献报道,建立所需三维有限元模型。结果建立的膝关节三维有限元模型包括胫腓骨上段、股骨下段、胫股骨软骨层、胫股骨隧道、内外侧半月板、后交叉韧带、内外侧副韧带和髌韧带,几何形状良好。胫腓骨隧道和人工韧带的模拟巧妙简便,基本可以满足有限元分析的需要。结论采用MRI图像建立膝关节三维有限元模型切实可靠,能很好地模拟膝关节内部的真实解剖结构及前交叉韧带重建术中的胫股骨隧道。     

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。     

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。     

电针治疗膝骨性关节炎患者上下楼梯的三维有限元分析

针对电针治疗膝骨性关节炎患者上下楼梯运动生物力学特性改变进行有限元仿真研究,对比分析膝关节生物力学行为改变与电针治疗疗效的相关性.基于CT和MRI图像数据,结合Mimics和Geomagic医学图像处理软件,建立人体膝关节下楼梯屈曲15°和上楼梯屈曲50°时的三维有限元模型,模型包括股骨、胫骨、腓骨、内外侧半月板、股骨...     

前交叉韧带重建术后关节粘连患者在体胫股关节运动学分析

目的 定量分析前交叉韧带重建(anterior cruciate ligament reconstruction, ACLR)术后关节粘连患者在体胫股关节 6 自由度的运动学特征。 方法 纳入 15 例 ACLR 术后关节粘连患者和 15 例健康受试者,运用便携式膝关节三维运动分析系统采集受试者负重屈膝和非负重屈膝时胫股相对于股骨的运动轨迹,获取胫股关节 6 自由度的运动学数据。 结果 与健康人相比,负重屈膝 30°、45°、60°和 75°时,膝关节粘连患者患侧胫骨内旋角度明显减少(P<0. 001);负重屈膝 30° 和 45° 时,膝关节粘连患者患侧胫骨相对于股骨的外翻角度较健康人明显减小(P<0. 05)。 非负重屈膝 75°时,膝关节粘连患者患侧胫骨内移距离较健康人明显减少(P<0. 05)。 结论 关节粘连限制了胫骨相对于股骨的旋转和内外移,对于胫骨相对于股骨的前后移动影响不大。 因此,临床上应该利用各种治疗手段松解股骨内外侧沟的粘连和外侧副韧带挛缩,解决旋转和内外移动受限的问题,以最大程度恢复膝关节功能。     

伤科手法治疗腰椎间盘突出症的运动学研究

为探索中医手法治疗腰椎间盘突出症的运动学规律和机制,选取上海交通大学附属瑞金医院魏氏伤科手法中的经典“悬足压膝”和“腰部提拉”手法动作作为研究对象。对10名健康青年男性施加手法动作,并通过三维运动捕捉系统采集手法作用时受试者的5次运动学数据,定义人体相对关节坐标系,并通过Visual3D软件建立人体三维运动模型。计算下肢髋关节、膝关节和踝关节的相对运动角度,并分解对应得到各关节的屈曲/伸展、外展/内收、轴向旋转运动,处理计算得到关节的平均运动角度和轨迹规律。统计各运动数据,分析运动的左右侧差异。结果表明,右侧髋关节的平均被动屈曲角度可达137.33°,被动伸展角度可达30.86°,这与解剖学上髋关节的被动最大角度以及其与膝关节位置相关的理论相一致,也验证了髋关节的极限屈曲/伸展角度与膝关节的位置有关,从而说明魏氏手法的运动学作用机理在于促进髋关节被动运动达到可达最大程度。同时发现,部分关节运动角度针对下肢惯用侧存在统计学上的左右侧差异(P<0.05)。该研究为手法的研究和定量评估提供新的研究方法。     

基于中国数字化人体的膝关节后外侧复合体的断层解剖与三维可视化

目的:拟基于薄层高精度的中国可视化人体数据(CVH)对膝关节后外侧复合体(PLC)进行断层解剖学与三维可视化研究。方法:选择CVH-1、CVH-2、CVH-5左右膝关节后外侧结构的CVH数据集,对PLC相关结构进行数据分割和三维数字化重建。结果:成功构建了CVH-1、CVH-2、CVH-5左右膝关节的三维模型,并对PLC的结构和毗邻关系进行多方位、多角度的三维可视化观察研究。结果:PLC主要由腓侧副韧带、腘腓韧带、弓状韧带、腘肌肌腱和股二头肌肌腱构成;髂胫束位于膝关节前外侧,位置相距PLC较远,功能与PLC结构存在差异,不属于PLC结构;3例CVH数据集均未见第3关节囊韧带和腓肠豆韧带。结论:推测膝关节手术中对腓侧副韧带、腘腓韧带、弓状韧带、腘肌肌腱进行解剖重建将有助于加强膝关节术后的稳定性。     

Insufficient lateral joint laxity after bicruciate-retaining total knee arthroplasty potentially influences kinematics during flexion: A biomechanical cadaveric study

BackgroundSoft tissue balancing in bicruciate-retaining (BCR) total knee arthroplasty (TKA) is a challenge that must be overcome to achieve excellent clinical outcomes. However, the optimal degree of joint laxity has yet to be clarified. This cadaveric study sought to examine joint laxity after BCR TKA using a navigation system.MethodsKnee joint laxity was quantified using an image-free navigation system in 8 intact fresh frozen cadavers under three conditions: the native knee, BCR TKA knee, and BCR TKA knee after anterior cruciate ligament resection. Rotational kinematics in the BCR TKA knee during flexion were compared according to whether joint laxity was increased or decreased.ResultsKnee joint laxity after BCR TKA under varus-valgus movement, anterior translation, and internal-external rotation loadings was similar to that of the native knee. However, lateral joint laxity was decreased during flexion in some cases. BCR TKA-treated knees with decreased lateral joint laxity at 90° of flexion demonstrated more limited tibial internal rotation in deep flexion than the native knee (p < 0.05). The loss of internal rotation in deep flexion was partly recovered by using a lateral insert with a posterior slope of +3°.ConclusionsRestoring optimal joint laxity was not always straightforward in BCR TKA if the 4 ligaments were preserved. Lateral joint laxity was potentially decreased in BCR TKA and may result in kinematic conflict during flexion. Surgeons should be aware of the need to achieve sufficient lateral joint laxity in this type of BCR TKA.     

Rotational kinematics differ between mild and severe valgus knees in total knee arthroplasty

BackgroundThere is no consensus regarding femorotibial rotational kinematics in total knee arthroplasty (TKA) for valgus knee deformity. Additionally, whether the degree of valgus deformity influences intraoperative rotational kinematics and postoperative clinical scores remains unclear. The objectives of this study were to investigate whether the valgus angle is associated with intraoperative rotational kinematics in TKA for valgus knee deformity and to examine the relationship between rotational kinematics and postoperative clinical results.Materials and methodsA total of 24 knees with valgus deformity for TKA were included in this study and were divided into two groups depending on the femorotibial angle (FTA); there were 11 knees in the severe valgus group (FTA < 160°) and 13 knees in the mild valgus group (FTA ≥ 160°). Intraoperative femorotibial rotational kinematics from knee extension to flexion were evaluated using an image-free navigation system and postoperative clinical results (range of motion and subjective outcomes) were evaluated 1 year postoperatively. All parameters were compared between the two groups.ResultMild valgus knee showed tibial internal rotation during knee flexion before implantation, whereas severe valgus knee showed tibial external rotation during knee flexion before implantation. The postoperative flexion angle was positively correlated with the tibial internal rotation angle after implantation in the mild valgus group only.ConclusionIntraoperative rotational kinematics before implantation differed between mild and severe valgus knee deformity in TKA. Intraoperative tibial rotation influenced the postoperative knee flexion angle in mild, but not severe, valgus knee deformity. Ideal postoperative rotational kinematics may be different between the two groups and the difference may be taken into consideration in implant selections and surgical techniques.     

Characteristic kinematics of floor-sitting activities after posterior-stabilized total knee arthroplasty determined using model-based shape-matching techniques

BackgroundDetailed kinematics of floor-sitting activities after total knee arthroplasty (TKA) have not been well explored. Knee kinematics of cross-legged sitting, seiza-sitting, and side-sitting after TKA were examined to clarify the differences in tibiofemoral kinematics of each activity.MethodsSubjects were 40 knees in 20 osteoarthritic patients who underwent bilateral TKA with a high-flexion fixed-bearing posterior-stabilized prosthesis. Dynamic radiographs of floor-sitting activities were taken, and the knee kinematics were compared among the three activities. The patients were also divided into two groups (possible/easy group and impossible/no-try group) for each activity, and group comparisons were conducted.ResultsThe maximum implant flexion angle was significantly greater in seiza-sitting. In valgus/varus rotation, seiza-sitting demonstrated neutral rotation, while cross-legged sitting showed varus of about 10°, and side-sitting exhibited valgus. In tibial internal/external rotation, seiza-sitting demonstrated a constant rotational angle, while cross-legged sitting showed tibial internal rotation with flexion, and side-sitting exhibited tibial external rotation with flexion. The kinematic pathway during deep flexion illustrated the medial pivot pattern in cross-legged sitting, a small amount of bicondylar rollback in seiza-sitting, and the weak lateral pivot pattern in side-sitting. A greater flexion angle was the important factor for the performance of each floor-sitting activity followed by varus laxity at 10° knee flexion.ConclusionsThis study successfully revealed characteristic kinematic patterns of TKA knees in three floor-sitting activities. Obtaining a greater knee flexion with adequate lateral laxity is the key to enhancing postoperative floor-sitting activities.     

Patellar resurfacing has minimal impact on in vitro tibiofemoral kinematics during deep knee flexion in total knee arthroplasty

BackgroundWhile patellar resurfacing can affect patellofemoral kinematics, the effect on tibiofemoral kinematics is unknown. We hypothesized that patellar resurfacing would affect tibiofemoral kinematics during deep knee flexion due to biomechanical alteration of the extensor mechanism.MethodsWe performed cruciate-retaining TKA in fresh-frozen human cadaveric knees (N = 5) and recorded fluoroscopic kinematics during deep knee flexion before and after the patellar resurfacing. To simulate deep knee flexion, cadaver knees were tested on a dynamic, quadriceps-driven, closed-kinetic chain simulator based on the Oxford knee rig design under loads equivalent to stair climbing. To measure knee kinematics, a 2-dimensional to 3-dimensional fluoroscopic registration technique was used. Component rotation, varus-valgus angle, and anteroposterior translation of medial and lateral contact points of the femoral component relative to the tibial component were calculated over the range of flexion.ResultsThere were no significant differences in femoral component external rotation (before patellar resurfacing: 6.6 ± 2.3°, after patellar resurfacing: 7.2 ± 1.8°, p = 0.36), and less than 1° difference in femorotibial varus-valgus angle between patellar resurfacing and non-resurfacing (p = 0.01). For both conditions, the medial and lateral femorotibial contact points moved posteriorly from 0° to 30° of flexion, but not beyond 30° of flexion. At 10° of flexion, after patellar resurfacing, the medial contact point was more anteriorly located than before patellar resurfacing.ConclusionDespite the potential for alteration of the knee extensor biomechanics, patellar resurfacing had minimal effect on tibiofemoral kinematics. Patellar resurfacing, if performed adequately, is unlikely to affect postoperative knee function.     

Kinematics of a cementless mobile bearing posterior cruciate ligament-retaining total knee arthroplasty

Mobile bearing (MB) total knee arthroplasty (TKA) was developed to provide low contact stress and unconstrained joint motion. We studied a consecutive series of 41 knees with mobile-bearing, posterior cruciate-retaining (CR) TKAs to determine if kinematics resembled normal knees or if kinematics changed over time. Patients were studied at 3 and 21 months average follow-up with weight-bearing radiographs at full extension, 30° flexion and maximum flexion. Shape-matching techniques were used to measure TKA kinematics. Implant hyperextension, maximum flexion and total ROM increased with follow-up. Tibial rotation and condylar translations did not change with time. The medial condyle did not translate from extension to 30°, but translated 5 mm anteriorly from 30° to maximum flexion. Lateral condylar translation was 3 mm posterior from extension to 30°, with no translation from 30° to maximum flexion. Tibiofemoral kinematics in CR-MB-TKAs were stable over time, but did not replicate motions observed in healthy knees. The mobile tibial insert showed rotation and translation at both follow-up examinations, but the patterns of translation were not predictable.     

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.     

In vivo kinematic comparison before and after mobile-bearing unicompartmental knee arthroplasty during high-flexion activities

BackgroundMany patients who undergo unicompartmental knee arthroplasty (UKA) have an expectation that their knee flexion would increase following its replacement. Additionally, the survival rate of mobile-bearing UKA (MB-UKA) is high. However, the effect on the patient's kinematics remains unknown. This study aimed to clarify the kinematic effect of MB-UKA knees during high-flexion activities by comparing the in vivo kinematics before and after surgery.MethodsA squatting motion was performed under fluoroscopic surveillance in the sagittal plane before and after MB-UKA. To estimate the spatial position and orientation of the knee, a two-dimensional/three-dimensional registration technique was used. The femoral rotation and varus–valgus angle relative to the tibia and anteroposterior (AP) translation of the medial and lateral side of the femur on the plane perpendicular to the tibial mechanical axis in each flexion angle were evaluated.ResultsRegarding the varus–valgus angle, the preoperative knees indicated a significant varus alignment compared with the postoperative knees from 10° to 60° of flexion. There were no significant differences in the femoral rotation angle, AP translation, and kinematic pathway before and after MB-UKA in the mid-flexion of the range of motion.ConclusionThere were differences between the varus–valgus knee kinematics before and after MB-UKA, from 10 to 60° of flexion, but no difference from midrange of flexion to deep flexion. In addition, the rotational knee kinematics before and after MB-UKA was not significantly different.     

Comparison of intraoperative kinematics and their influence on the clinical outcomes between posterior stabilized total knee arthroplasty and bi-cruciate stabilized total knee arthroplasty

BackgroundOf all the intraoperative kinematic parameters recorded using navigation systems, femorotibial rotational alignment is reportedly associated with the clinical outcomes of cruciate retaining and posterior stabilized (PS) total knee arthroplasty (TKA). However, to our knowledge, there are no reports on the relationship of newly designed bi-cruciate stabilized (BCS) TKA and intraoperative rotational kinematics. We aimed to clarify and compare the relationships between the intraoperative kinematics and clinical outcomes of BCS TKA and PS TKA.MethodsWe compared the intraoperative rotational kinematics and clinical outcomes at two years postoperatively of 56 BCS TKA patients and 55 PS TKA patients. Further, we evaluated the relationship between the femorotibial rotational kinematics and clinical outcomes.ResultsThe maximum flexion angle and the pain subscale of the Knee injury and Osteoarthritis Outcome Score (KOOS) in BCS TKA were significantly better than those in PS TKA. The intraoperative kinematic data of BCS TKA showed “screw-home” movement, while that of PS TKA did not show this movement. The rotational angular differences between at maximum flexion angle and at 60° flexion of BCS TKA showed positive correlations with the improvement of KOOS pain, symptom, activity of daily living and sports subscales. The rotational angular differences between at maximum flexion angle and at 30° flexion in PS TKA showed positive correlations with the maximum flexion angle.ConclusionIntraoperative femorotibial rotational kinematics and its influence on the clinical outcomes were different between BCS and PS TKA. BCS TKA showed more normal-like kinematics and better clinical results than PS TKA.     

In vivo kinematic analysis of posterior-stabilized total knee arthroplasty for the valgus knee operated by the gap-balancing technique

BackgroundMost in vivo kinematic studies of total knee arthroplasty (TKA) report on the varus knee. The objective of the present study was to evaluate in vivo kinematics of a posterior-stabilized fixed-bearing TKA operated on a valgus knee during knee bending in weight-bearing (WB) and non-weight-bearing (NWB).MethodsA total of sixteen valgus knees in 12 cases that underwent TKA with Scorpio NRG PS knee prosthesis and that were operated on using the gap balancing technique were evaluated. We evaluated the in vivo kinematics of the knee using fluoroscopy and femorotibial translation relative to the tibial tray using a 2-dimensional to 3-dimensional registration technique.ResultsThe average flexion angle was 111.3° ± 7.5° in WB and 114.9° ± 8.4° in NWB. The femoral component demonstrated a mean external rotation of 5.9° ± 5.8° in WB and 7.4° ± 5.2° in NWB. In WB and NWB, the femoral component showed a medial pivot pattern from 0° to midflexion and a bicondylar rollback pattern from midflexion to full flexion. The medial condyle moved similarly in the WB condition and in the NWB condition. The lateral condyle moved posteriorly at a slightly earlier angle during the WB condition than during the NWB condition.ConclusionsWe conclude that similar kinematics after TKA can be obtained with the gap balancing technique for the preoperative valgus deformity when compared to the kinematics of a normal knee, even though the magnitude of external rotation was small. Level of evidence: IV.