Loss of neuromuscular control related to motion in the acutely ACL-injured knee: an experimental study

Ligamentomuscular and muscular stretch reflexes are known to contribute to knee joint stability. After anterior cruciate ligament (ACL) injury, a more intense and adjusted muscular response is required to maintain joint stability, but this neuromuscular control of the knee has not been clearly proved. The aim of the study is to record electromyography (EMG) signal and muscular fibre length variations in quadriceps and hamstrings of the knee with and without ACL, and to analyze and integrate the ligament strain and the muscular reaction to forced anterior tibial translation (ATT). In 17 knees from 12 cats, EMG electrodes and ultrasonomicrometry crystals were inserted into four main periarticular muscles, with strain gauges on periarticular ligament insertions. Their output signal was compared before and after ACL surgical section in series of ATT (at 90 degrees and 30 degrees knee flexion), and also during knee flexion and extension. Linear regression analysis was performed between the EMG signal and muscular fibre length variations, and between the EMG signal and the strain on ligament insertions, in the search of this reflex neuromuscular response. In the ACL deficient knees, the studied muscles showed a poor adjustment to motion of EMG firing, inversely to controls. The muscle stretch reflexes showed poorer correlation with post-peak EMG activity than the ligaments. ATT control depended mainly on hamstrings activity in control knees, whereas in unstable knees, quadriceps activity was associated with more tibial translation. Acute ACL-deficient knees showed poor neuromuscular control with weak ligamentomuscular reflexes and no muscular stretch reflexes, suggesting the ineffectiveness of acute muscular reaction to provide early mechanical knee stabilization after injury.     

前交叉韧带损伤后关节腔内后交叉韧带中基质金属蛋白酶-II活性的研究

目的 初步探索前交叉韧带(anterior cruciate ligament,ACL)损伤后后交叉韧带(posterior cruciate ligament,PCL)中基质金属蛋白酶(MMP-2)的表达量变化情况。方法 用本实验室已获专利的大鼠前交叉韧带瞬时扭转损伤装置将大鼠ACL损伤后在ex-vivo水平上用酶谱分析的方法检测PCL组织中所释放MMP-2的情况。结果 ACL损伤后的第1,2,3天后,PCL组织培养上清液中的MMP-2表达量呈时间依赖性递增趋势。结论 ACL急性损伤后, PCL组织释放大量MMP-2至关节液中。     

LARS人工韧带同时重建前、后交叉韧带

目的探讨关节镜下LARS（Ligament Advanced Reinforcement System，LARS）人工韧带同时重建前（An-terior cruciate ligament，ACL）、后交叉韧带（posterior cruciate ligament，PCL）的方法和临床疗效。方法从2006年1月至2007年4月，用LARS人工韧带同时重建ACL、PCL2例。应用Lysholm功能评分表评估膝关节功能，采用抽屉实验检查膝关节前后松弛度。结果2例均获得随访，随访时间分别为8月、3月。2例患者术后患膝关节不稳定症状消失，胫骨后坠征阴性，前、后抽屉试验阴性。膝关节功能评估采用Lysholm功能评分标准，术前平均分别为45．6±7．6分，术后平均为80．3±9．1分。结论关节镜下应用LARS人工韧带同时重建ACL、PCL可更好地恢复膝芙节的稳定性，且创伤小，并发症少，近期疗效满意，但远期效果仍需进一步观察。     

Mechanoreceptors of the ligaments and tendons around the knee

Proprioceptive inputs from the joints and limbs arise from mechanoreceptors in the muscles, ligaments and tendons. The knee joint has a wide range of movements, and proper neuroanatomical organization is critical for knee stability. Four ligaments (the anterior (ACL) and posterior (PCL) cruciate ligaments and the medial (MCL) and lateral (LCL) collateral ligaments) and four tendons (the semitendinosus (STT), gracilis (GT), popliteal (PoT), and patellar (PaT) tendons) from eight fresh frozen cadavers were harvested. Each harvested tissue was divided into its bone insertion side and its tendinous part for immunohistochemical examination using S100 staining. Freeman–Wyke's classification was used to identify the mechanoreceptors. The mechanoreceptors were usually located close to the bone insertion. Free nerve endings followed by Ruffini endings were the most common mechanoreceptors overall. No Pacini corpuscles were observed; free nerve endings and Golgi‐like endings were most frequent in the PCL (PCL‐PaT: P = 0.0.1, PCL‐STT: P = 0.00), and Ruffini endings in the popliteal tendon (PoT‐PaT: P = 0.00, Pot‐STT: P = 0.00, PoT‐LCL: P = 0.00, PoT‐GT: P = 0.00, PoT‐ACL: P = 0.09). The cruciate ligaments had more mechanoreceptors than the medial structures (MS) or the patellar tendon (CR‐Pat: P = 0.000, CR‐MS: P = 0.01). The differences in mechanoreceptor distributions between the ligaments and tendons could reflect the different roles of these structures in the dynamic coordination of knee motion. Clin. Anat. 29:789–795, 2016. © 2016 Wiley Periodicals, Inc.     

Biomechanics of the knee joint in flexion under various quadriceps forces

Bioemchanics of the entire knee joint including tibiofemoral and patellofemoral joints were investigated at different flexion angles (0° to 90°) and quadriceps forces (3, 137, and 411 N). In particular, the effect of changes in location and magnitude of restraining force that counterbalances the isometric extensor moment on predictions was investigated. The model consisted of three bony structures and their articular cartilage layers, menisci, principal ligaments, patellar tendon, and quadriceps muscle. Quadriceps forces significantly increased the anterior cruciate ligament, patellar tendon, and contact forces/areas as well as the joint resistant moment. Joint flexion, however, substantially diminished them all with the exception of the patellofemoral contact force/area that markedly increased in flexion. When resisting extensor moment by a force applied on the tibia, the force in cruciate ligaments and tibial translation significantly altered as a function of magnitude and location of the restraining force. Quadriceps activation generated large ACL forces at full extension suggesting that post ACL reconstruction exercises should avoid large quadriceps exertions at near full extension angles. In isometric extension exercises against a force on the tibia, larger restraining force and its more proximal location to the joint substantially decreased forces in the anterior cruciate ligament at small flexion angles whereas they significantly increased forces in the posterior cruciate ligament at larger flexion angles.     

膝关节脱位致多韧带损伤Ⅰ期修复重建的疗效

目的:探讨膝关节脱位致膝关节前、后交叉韧带及内侧副韧带损伤后一期修复的疗效.方法:回顾性分析28例膝关节脱位致膝关节前、后交叉韧带损伤及合并内侧副韧带Ⅲ度损伤或完全断裂的患者行Ⅰ期修复重建的疗效.其中车祸事故伤22例,军事训练伤4例,高台坠落伤2例.损伤至手术时间6～17(平均7)d.膝关节Lysholm评分为21.7±6.52,国际膝关节文献委员会(International Knee Documentation Committee,IKDC)评分为17.42±11.56,关节活动范围为(27.2±19.6)°.合并内外侧半月板复合裂伤15例.通过关节镜下探查清理关节腔周围合并损伤后,采用患者自体半腱肌股薄肌肌腱重建前交叉韧带(anterior cruciate ligament,ACL),人工韧带(ligament advanced reinforcement system,LARS),韧带重建后交叉韧带(poster cruciate ligament,PCL),并使用带线锚钉修复内侧副韧带(medial cruciate ligament,MCL).结果:患者出院后均获随访,随访时间为6～24(平均18.2)个月.术后2年Lysholm膝关节功能评分为89.23±9.23,关节活动范围116.56°±12.8°,IKDC评分为88.74±8.74,与术前评分对比差异有统计学意义(P＜0.05).结论:在膝关节脱位致多韧带损伤的治疗方案中,Ⅰ期关节镜下行ACL和PCL重建术,并使用带线锚钉修补MCL断端,患者受到的损伤小,术后膝关节的稳定性恢复佳,通过进一步的康复理疗,关节粘连发生率较低,可得到相对满意的近期疗效,此方法值得临床参考并借鉴.     

人工韧带修复膝关节交叉韧带损伤

背景：以往治疗膝关节交叉韧带损伤的主要手段是移植重建,最常用的移植材料为自体的骨髌腱骨、半腱肌腱和股薄肌腱。但由于此类移植物存在取材区并发症及韧带化过程中的各种问题,近年来人工韧带的研究受到重视。 目的：认识膝关节交叉韧带的结构及血供特点,以及膝关节交叉韧带损伤后人工韧带重建治疗机制与临床应用特点。 方法：①分析膝关节前、后交叉韧带的组织结构,功能学特点以及血供差异。②分析膝关节前、后交叉韧带损伤的类型及生物力学机制。③分析修复膝关节交叉韧带损伤的材料学分类及特点。④分析人工韧带修复后影响关节稳定性的因素。 结果与结论：修复膝关节前、后交叉韧带损伤时,应首先考虑到前、后交叉韧带的功能及血供情况,选择合适的重建物,使重建时过程简化,操作简单,重建材料的组织相容性较好,达到修复后的解剖与功能的双重建。     

Evaluation of the walking pattern in two types of patients with anterior cruciate ligament deficiency: copers and non-copers

The purpose of the present study was to investigate whether different walking patterns in healthy subjects and in coper and non-coper subjects with deficient anterior cruciate ligaments could be quantified. An inverse dynamics approach was used to calculate joint kinematics and kinetics for flexion and extension. EMG signals of the hamstrings and quadriceps muscles were recorded. The results showed that the peak knee flexion angle was greater in the copers than in the controls. There was a positive correlation between the peak knee extensor moment and peak knee flexion angle. Furthermore, at a given peak knee flexion angle, the peak knee extensor moment was significantly larger in the controls than in the non-copers. The hip extensor moment in the copers was significantly larger than that of the non-copers and the controls. In conclusion, the three groups walked according to different patterns. It is suggested that the copers stabilized their knee joint by co-contraction of the hamstrings and quadriceps muscles, while the non-copers lacked this ability. Instead, the non-copers reduced the knee extensor moment in order to decrease anterior displacement of the tibia. The walking pattern differences observed between the copers and non-copers may explain their different post-injury activity levels. Electronic Publication     

四象限分区法用于前交叉韧带多纤维束动态受力分析

目的介绍四象限分区法在测量国人前交叉韧带(anterior cruciate ligament,ACL)多纤维束动态受力分析中的应用;并探讨了膝关节活动中ACL多纤维束动态力学特性。方法采集8侧正常国人膝关节标本,评估标本完整性后向ACL胫骨止点中心做斜行骨隧道,游离ACL胫骨侧止点,以四象限法平均分为4个区:1区,后内区;2区,后外区;3区,前外区;4区,前内区。将4个区的附着纤维束分别连接至自制"膝关节交叉韧带测力计"传感器上,连接系统后分别在膝关节屈曲90o位和伸直0o位将ACL各纤维束张力调零后测量膝关节4自由度(屈伸、内外翻、内外旋、前抽屉试验)内各纤维束的动态受力变化。结果2区和3区纤维束在由屈至伸的过程中所受张力逐渐增大,2区纤维束最大为22.52N±8.60N(30o),3区纤维束最大为13.98N±3.47N(0o);3区和4区纤维束在由伸至屈的过程中张力逐渐增大,4区纤维束最大为14.68N±5.29N(90o),3区纤维束最大为9.84N±5.06N(60o)。所有纤维束在外翻、内外旋、前抽屉试验中张力增加。内翻试验中所有纤维束张力增加不明显,1区纤维束在3个膝关节自由度内张力变化不明显。结论膝关节伸直过程中受力承担最大作用的纤维束主要分布在ACL胫骨止点后外分区内,屈曲位的主要承力纤维分布于前内分区,前外分区则有以上两种纤维束的附着,可能为ACL纤维束中动态受力连续变化的中转部分所在位置。四象限分区法测量ACL多纤维束动态受力有助于利用标准分区方法了解ACL多纤维束动态受力连续变化趋势,为进一步深入探讨ACL多纤维束连续动态受力提供了参考依据。     

Does a torn anterior cruciate ligament lead to change in the central nervous drive of the knee extensors?

Summary Integrated surface electromyograms of the three superficial parts of the quadriceps and isokinetic knee extensor maximum torque and power production were recorded simultaneously and at different angular velocities in both legs in 11 male subjects with unilateral tear of the anterior cruciate ligament. The cross-sectional area (CSA) of the thigh and its muscular components were measured by computerized tomography. The principal findings were a small but significant decrease in quadriceps CSA on the affected side; a decreased active, but not passive, range of movement; decreased mechanical output, whether or not corrected for differences in CSA; and decreased electrornyographic activity — particularly in rectus femoris. These findings suggest that the reason for the decreased maximum and total knee extensor performance seen in these patients is a change in knee joint receptor afferent inflow.     

Reconstruction of patellar tendon rupture after anterior cruciate ligament reconstruction: a case report

Patellar tendon rupture following use of its central third for anterior cruciate ligament (ACL) reconstruction is a rare disabling injury that is technically difficult to repair. We report one case of patellar tendon rupture after harvesting the mid-third for ACL reconstruction. A number of different surgical methods exist for reconstructing patellar tendon ruptures. Here we report a case using a bone-tendon-bone (BTB) allograft, followed by a multiple-wire loop reinforcement with no postoperative immobilisation. One year after operation, our patient had regained full knee extension and flexion. Insall Salvati index on the operated side was identical to the uninjured side. The patient had good quadriceps strength, and isokinetic muscle testing showed no deficit in his right leg. He was able to return to professional handball without limitation.     

Characterization of collagenous and elastic fiber systems and microvasculature of human cruciate ligaments: An electronmicroscopic and stereologic study

The cruciate ligaments of 35 human knee joints were analyzed by the combined use of immunohistochemistry and transmission and scanning electron microscopy. The results were verified by morphometric analyses. The anterior cruciate ligament (ACL) had a more twisted and complex architecture compared to the posterior cruciate ligament (PCL). The PCL showed significantly (p < 0,05) thicker fibril diameters (x = 84,2 nm, s = 25,8 nm vs. x = 79,3 nm, s = 19,9 nm) and a higher total cross-sectional area (252,00 mm² vs. 208,0. 5 mm²) than the ACL. In both ligaments, type III collagen was detected using monoclonal antibodies. The ACL revealed more type VI but less type IV collagen than the PCL. The vascularization of the ACL revealed an age-dependent pattern and was significantly (p < 0,001) less well marked than in the PCL. The results reflect the poor vascular supply of the ACL in the human knee joint. The complex collagen architecture and the lower vascularization of the ACL in comparison with the PCL may contribute to poor surgical results after traumatic anterior cruciate ligament rupture. © 1993 Wiley-Liss, Inc.     

Comparison of knee joint functional laxity after total knee replacement with posterior cruciate-retaining and cruciate-substituting prostheses

The objective of this study was to measure three-dimensional knee motion or functional laxity with implants which either retained the posterior cruciate ligament (PCL+) in ten patients, or substituted for excised PCL with a posterior stabilized articulating surface (PCL-S) in ten patients. The intent was to identify the specific influence and significance of the presence of the PCL under active flexion and extension. Internal-external rotation (screw home movement) and anterior-posterior translation (femoral rollback phenomena) with active extension and flexion were chosen to characterize knee joint functional laxity, and were measured using an instrumented spatial linkage. Knees with a PCL+ implant exhibited both screw home movement and femoral rollback, while knees with a PCL-S design exhibited only femoral rollback. A knee with a PCL+ implant was more able to reproduce the normal kinematics of the screw home movement and femoral rollback, compared to a PCL-S design.     

The restraining function of the cruciate ligaments on hyperextension and hyperflexion of the human knee joint

Each of the cruciate ligaments contains functionally different fiber groups; one fiber bundle is always taut; numerous others are taut in intermediate or extreme positions. The bulk of the fibers of the anterior cruciate ligament (ACL) is taut in maximal extension, while that of the posterior cruciate ligament (PCL) is taut in the intermediate positions and in maximal flexion. Fibers taut in extreme positions serve as restraints: during hyperextension, the ACL restrains forward migration of its tibial attachment, while the PCL interacts with other structures to prevent posterior opening of the joint. The inverse situation occurs in hyperflexion. Cruciate fibers are dissimilar in length and angular arrangement so that, when movements are restrained, they lengthen to different extents. To define this phenomenon in quantitative terms, the term isokolyons was coined for lines from which fibers showing identical elongation in percentage on exposure to a force take their origin.     

非接触性前交叉韧带损伤特点及机制的研究进展

前交叉韧带断裂是膝关节最常见运动损伤之一,大部分是非接触性原因造成的。理解前交叉韧带受力和损伤机制对预防和治疗损伤有重要意义。本文综述了国内外对前交叉韧带损伤特点及其受力和损伤机制的研究结果。研究表明,下肢矢状面的生物力学是前交叉韧带受力的主要影响因素,如较小的膝关节屈角,较大的地面反作用力,较大的股四头肌力。其中较大的地面反作用力引发较大的股四头肌力和胫骨近端向前的拉力从而增加前交叉韧带负荷。较小的膝关节角合并较大的髌韧带与胫骨夹角和前交叉韧带倾斜角会增大韧带负荷。交叉韧带并不是承受膝关节内、外翻和内旋     

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。     

创伤后膝骨关节炎发展中前交叉韧带损伤的作用与意义#br#

文题释义： 创伤后骨关节炎：又称外伤性骨关节炎、损伤性骨关节炎,它是由创伤引起的以关节软骨的退化变性和继发的关节周围骨质增生为主要病理变化,以关节疼痛、活动障碍为主要临床表现的一种疾病。任何年龄组均可发病,但以青壮年多见,多发于创伤后、承重失衡及活动负重过度的关节。 前交叉韧带损伤：一般出现在体育运动中,橄榄球、篮球、足球、滑雪等项目尤其多见。除了膝关节与他人碰撞致伤外,78%的前交叉韧带损伤为非接触性,常发生于落地、急停及暴力扭转等动作。足球运动中,移位防守以及奔跑中踢球相对危险;篮球运动中,侧跳转身以及单腿落地相对危险;在滑雪运动中滑雪板前端受阻时,膝关节外翻旋转,是较为典型的前交叉韧带非接触性损伤机制。 背景：前交叉韧带具有稳定膝关节、限制胫股关节在胫骨前平移和旋转的作用,大多数前交叉韧带重建患者膝关节疼痛和膝关节不稳的概率增加。创伤后膝骨关节炎是前交叉韧带损伤后的严重并发症,目前其机制尚不完全清楚。 目的：综述前交叉韧带损伤与创伤后膝骨关节炎发病因素之间的关系,从而为创伤后膝骨关节炎的治疗提供帮助。 方法：第一作者应用计算机检索PubMed数据库自建库以来至2019年10月的相关文章,英文检索词“ACL injury,traumatic knee osteoarthritis,ACL reconstruction,meniscus status,body mass index,cartilage injury,age,graft selection,time interval between injury and surgery”。共检索到123篇相关文献,66篇文献符合纳入标准。 结果与结论：①半月板状态、体质量指数、软骨损伤、年龄、移植物选择、受伤与手术之间的时间间隔这些因素会对创伤后膝骨关节炎的发展产生影响;②虽然前交叉韧带重建主要是恢复前交叉韧带断裂后的稳定性,该过程的一个长期目标是降低膝关节骨关节炎产生的风险,并维持关节长期处于健康状态;③患者前交叉韧带断裂后伴随半月板损伤需要进行半月板切除也是导致膝骨关节炎的原因,这很可能是由于关节的承受力减弱和关节运动学改变所致。 ORCID: 0000-0001-9413-439X(韩广弢) 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     

Biomechanical study of a computer simulated reconstruction of the anterior cruciate ligament (ACL)

The purpose of the study was to use a computer simulation of various surgical techniques for reconstruction of the anterior cruciate ligament (ACL) to study graft biomechanics. To ensure the normal function of the cruciate ligament and, consequently, normal kinematics of the knee joint, the complex structure of the normal ACL must be built into the graft.

Methods. First the ACL was modeled and then a reconstruction of the ACL was simulated on a computer model of the cadaveric knee. Biomechanical patterns of the ACL and the modeled grafts in different spatial orientations and positions of the femoral attachments were studied. Isometricity of the peripheral and central fibers of the ACL and grafts was measured and the average fiber length change and isometric pattern of fibers in the graft were compared.

Results. None of the ACL fibers is isometric and fiber length change varies with individual fibers of the original ligament or graft. The average length change of graft fibers depends on the position of the femoral attachment in the sagittal plane. It is smaller in anterior positions in relation to the geometric center of the femoral origin of the ACL, and larger in posterior positions. The isometric pattern of fibers in the graft in isometric orientations resembles most closely the pattern of the original ACL.

Conclusions. A computer simulation of various surgical techniques of reconstruction of the ACL can be successfully used for the study of biomechanics. The most significant kinematic characteristics of the ACL is gradual recruitment of graft fibers during knee extension, which can be defined as the pattern of isometricity. The isometric pattern of the graft is primarily influenced by spatial orientation.