Comparison of drop jump landing biomechanics and asymmetry among adolescents with hamstring,patellar and quadriceps tendon autografts for anterior cruciate ligament reconstruction

Background

Adolescent anterior cruciate ligament reconstruction (ACLR) commonly utilizes hamstring (HT), patellar (PT) or quadriceps (QT) tendon autografts, but consensus is lacking regarding optimal graft choice. This study compared landing biomechanics and asymmetries among ACLR patients with HT, PT and QT grafts and uninjured controls.

Biomechanical simulation of anterior cruciate ligament strain for sports injury prevention

The purpose of this study was to quantify in vivo anterior cruciate ligament (ACL) strain by computer simulation, which includes a marker-based biomechanical model and a skeletal geometry model. Kinematic data collected by a motion capture system was used as the input and ACL strain during the movement time period was the output. Case studies were conducted to simulate ACL strain during jump landing, running and sidestep cutting activities. The simulation results were analysed and compared with previous findings in literature. The results show that the simulation is a useful tool in understanding ACL injury mechanisms related to sports activities.     

High variability in anterior cruciate ligament femoral footprint: Implications for anatomical anterior cruciate ligament reconstruction

BackgroundThe study aimed to (1) investigate the variability of the femoral ACL center in ACL-ruptured patients, (2) identify whether the currently available over-the-top femoral ACL guides could allow for anatomical reconstruction of the native ACL footprint.Material and methodsMagnetic resonance images of 95 knees with an ACL rupture were used to create three-dimensional models of the femur. The femoral ACL footprint area was outlined on each model, and the location of the femoral ACL center was reported using an anatomical coordinate system. The distance of the femoral ACL center from the over-the-top position was measured.ResultsThe femoral ACL center demonstrated a high intersubject variability ranging from 1.8 mm (9%) to 12.3 mm (60%) posterior and from 7.7 mm (37%) distal to 4.8 mm (23%) proximal using the posterior condyle circle reference. The average distance of the femoral ACL center from the over-the-top position was 1.9 ± 1.5 mm posterior and 13.8 ± 2.7 mm distal, respectively. The contemporary over-the-top femoral ACL aimers could restore the femoral ACL center in only 6.5% of the patients.ConclusionsThe femoral ACL center demonstrated a high variation on its location, which resulted in a high intersubject variability from the over-the-top position. The contemporary over-the-top femoral tunnel guides do not provide sufficient offset to allow for an anatomical ACL reconstruction. Anteromedial-portal specific femoral ACL guides with a femoral offset ranging from 10 to 18 mm in the proximal/distal direction are required to restore the native ACL footprint.     

自体单束前交叉韧带移植重建不同股骨隧道位置对髌股关节的影响

背景:研究显示,关节镜下膝关节单束前交叉韧带重建可以恢复膝关节的前向稳定性,但膝关节旋转稳定性及髌股关节匹配程度却受股骨及胫骨隧道中心位置的影响。目的:分析青壮年前交叉韧带重建不同股骨隧道中心点位置与髌股关节软骨情况及髌骨倾斜的关系,同时对患者研究因素进行相关性分析,从而进一步探讨对髌股关节软骨及髌骨位置影响最小的股骨隧道位置的选择。方法:将70例经过术前磁共振检查、查体及术中关节镜探查明确诊断为前交叉韧带断裂的患者,根据随机数字的奇偶将所有患者分为类等长组(使用股骨定位器定位于髁间窝外侧壁过顶点远端7 mm打入克氏针)和类解剖组(于髁间窝外侧壁、原前交叉韧带足印中心方向打入克氏针)。采用标准化网格系统上的近-远-前-后平面对股骨隧道中心坐标进行评估;前-后-内-外平面对胫骨隧道中心坐标进行评估,标记为象限Y%和象限X%。比较两组患者基线数据、髌股外侧角的差值、软骨定量T2值有无差异以及各研究因素之间相关性。研究方案的实施符合安徽医科大学第一附属医院的相关伦理要求,参与试验的患者均签署了"知情同意书"。结果与结论:①类解剖与类等长两组之间基线数据之间无显著性差异;髌股外侧角差值类解剖组(0.57±0.33)°<类等长组(1.55±0.36)°(P<0.001);②类解剖组髌骨内侧、髌骨外侧、滑车软骨T2值均小于类等长对应值;③象限X%与髌股外侧角差值具有显著负相关性(R=-0.664,P<0.01);象限Y%与髌股外侧角差值呈正相关(R=0.804,P<0.01);髌股外侧角差值与滑车及髌骨外软骨T2值明显正相关(R=0.651,0.655,P<0.01);滑车及髌骨外侧软骨T2值与术后Lysholm评分呈负相关(R=-0.505,-0.529,P<0.01);象限Y%与髌骨外侧T2值高度相关(R=0.825,P<0.01),与滑车软骨T2值显著相关(R=0.798,P<0.01);象限X%与髌骨外侧及滑车软骨T2值呈显著负相关(R=-0.639,-0.657,P<0.01);④结果说明,通过对单束前交叉韧带重建术后早期髌股关节改变的研究,发现类解剖重建相对于类等长重建后,髌股关节软骨退变程度和髌骨倾斜角度更小,要求手术者尽可能将股骨隧道中心点位置放置于类解剖位置,从而最大限度的减少髌股关节的退变。     

非接触性前交叉韧带损伤的生物力学风险评估及预防

背景：非接触性前交叉韧带损伤占前交叉韧带损伤的80%,且多发生于青春期女性,如何对损伤的风险因素进行评估,用于高危人群的筛选,对有效预防损伤至关重要。 目的：对非接触性前交叉韧带损伤的生物力学风险因素和预防手段进行阐述,为非接触性前交叉韧带损伤的预防开辟新的思路。 方法：应用计算机在互联网检索PubMed数据库和CNKI数据库1979至2014年相关文献,在英文标题和摘要中以“on-contact anterior cruciate ligament, biomechanicas,risk factors”和“non-contact anterior cruciate ligament,prevention”等关键词搜索,中文文献以“前交叉韧带损伤,生物力学”为关键词,选择内容与非接触性前交叉韧带损伤生物力学分析和预防有关的文献。共纳入文献58篇。 结果与结论：应用生物力学评估的手段对参加运动项目的青少年人群进行筛查,对落地、急停、切步等高危动作中膝关节的运动学进行分析,发现非接触性前交叉韧带损伤的高风险人群。尽早预防性训练计划的干预可以提高运动表现、纵跳高度及膝关节动态负荷状态下的稳定性,发展平衡和提高腘绳肌的力量及核心控制能力,可以最大限度预防非接触性前交叉韧带损伤的发生。 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;组织工程全文链接：     

The effect of anterior cruciate ligament injury on knee joint function under a simulated muscle load: a three-dimensional computational simulation

Understanding the biomechanical effect of various factors on knee behavior after anterior cruciate ligament (ACL) injury or reconstruction is instrumental for the development of an optimal surgical treatment of ACL injury that can better restore normal knee function. This paper presents the application of a three-dimensional (3D) computational knee model for parametric studies of knee kinematics in response to simulated muscle loads. The knee model was constructed using the magnetic resonance images and biomechanical experimental data of the same cadaveric human knee specimen. The kinematics of the knee predicted by the computational model was compared with that measured from different specimens in a wide range of loading conditions and flexion angles. In general, the model predictions were within the range of experimental data. The model was then used to predict knee motion, ligament forces, and contact pressure in response to a simulated quadriceps force when the knee was ACL deficient. Partial ACL injury was simulated by reducing the stiffness of the ACL in the model. The results demonstrated that even with a reduction of 75% of the ACL stiffness, the ACL still carried a significant amount of the load (more than 58%) carried by an intact ACL. The kinematics (both tibial translation and rotation) varied less than 20% compared to that of the knee with intact ACL. The 3D computational model can be a powerful tool to simulate different variables that would influence knee function after ACL reconstruction, such as the initial tension of the ACL graft, the insertion sites of the graft, multibundle grafts, graft materials, and various physiological loading conditions. © 2002 Biomedical Engineering Society. PAC2002: 8719Ff, 8719Rr, 8719St     

膝关节前交叉韧带损伤的弥散张量成像观测

目的　为膝关节前交叉韧带损伤分度提供新的影像诊断依据。 方法　选取膝关节弥散张量成像扫描检查正常者100例和单侧前交叉韧带撕裂伤者100例,后者按照损伤程度分为Ⅰ~Ⅳ级,在工作站划分前交叉韧带损伤处及正常组相应部位感兴趣区,测量各向异性分数（fractional anisotropy,FA）和表观弥散系数（apparent diffusion coefficient,ADC）,生成纤维示踪图像。 结果　前交叉韧带损伤处与正常组相应部位的FA和ADC差异有统计学意义,损伤处的FA低于正常组,ADC高于正常组。前交叉韧带Ⅰ级、Ⅱ级、Ⅲ级、Ⅳ级损伤处的FA和ADC差异有统计学意义,FA随损伤程度增高而逐渐降低,与损伤程度呈负相关;ADC则逐渐增高,与损伤程度呈正相关。FA和ADC、纤维示踪成像及MRI诊断前交叉韧带损伤程度分级的灵敏度、特异度、准确度、阳性预测值及阴性预测值差异均有统计学意义,从高到低均依次为纤维示踪成像、FA和ADC、MRI。 结论　膝关节前交叉韧带损伤处的FA和ADC与损伤程度密切相关,纤维示踪成像可以提高损伤程度分级的准确率,弥散张量成像可以为前交叉韧带损伤分级提供更准确的影像诊断依据。     

Increasing pre-activation of the quadriceps muscle protects the anterior cruciate ligament during the landing phase of a jump: An in vitro simulation

We hypothesize that application of an unopposed quadriceps force coupled with an impulsive ground reaction force may induce anterior cruciate ligament (ACL) injury. This situation is similar to landing from a jump if only the quadriceps muscle is active; an unlikely but presumably dangerous circumstance. The purpose of this study was to test our hypothesis using in vitro simulation of jump landing. A jump-landing simulator was utilized. Nine cadaveric knees were tested at an initial flexion angle of 20°. Each ACL was instrumented with a differential variable reluctance transducer (DVRT). Quadriceps pre-activation forces (QPFs) ranging from 25 N to 700 N were applied to each knee, followed by an impulsive ground reaction force produced by a carriage-mounted drop weight (7 kg) that impulsively drove the ankle upward. ACL strain was monitored before landing due to application of QPF (pre-activation strain) and at landing due to application of the ground reaction force (landing strain). No ACLs were injured. Pre-activation strains exhibited a positive correlation with QPF (r = 0.674, p < 0.001) while landing strains showed a negative correlation (r = ? 0.235, p = 0.032). Total ACL strain (pre-activation + landing strain) showed no correlation with QPF (r = 0.023, p = 0.428). Our findings indicate that elevated QPF increases pre-activation strain but reduces the landing strain and is therefore protective post-landing. Overall, there is a complete lack of correlation between “total” ACL strain and QPF suggesting that the total strain in the ACL is independent of the QPF under the simulated conditions.     

Association of fibrosis in the infrapatellar fat pad and degenerative cartilage change of patellofemoral joint after anterior cruciate ligament reconstruction

Background

The purpose of this study was to evaluate the prevalence and risk factor of cartilage degeneration of the patellofemoral joint (PFJ) that was diagnosed by second-look arthroscopy.

人工韧带生物材料修复膝关节交叉韧带损伤：问题及前景

BACKGROUND: Related studies have confirmed that the experimental results and short-term clinical outcomes of artificial ligaments are satisfactory that the artificial ligaments can restore the stability of knee joint as soon as possible and ensure motor function. OBJECTIVE: To summarize the basic and clinical research progress of artificial ligaments. METHODS: The articles regarding artificial ligaments in repair of knee joint cruciate ligament injury were retrieved from Wanfang database, CNKI and PubMed database during 1985 to 2015 by computer. The keywords were “cruciate ligament injuries, artificial ligament, biological materials” in Chinese and English, respectively. RESULTS AND CONCLUSION: Compared with autologous and allogenic ligaments, artificial ligament has good mechanical properties, and can get sufficient tensile strength and joint stability immediately after implantation, so as to ensure the cruciate ligament reconstruction of the knee joint. Artificial ligament technology has experienced carbon fiber ligament, polyester material and stent artificial ligaments. As a new type of polyester artificial ligament, LARS artificial ligament shows a good biocompatibility, on which, cells can adhere, proliferate and differentiate well. However, the controversies over the use of artificial ligament still exist, and its long-term clinical effects still need further observation. Further researches regarding the material selection, shape bionic design, weaving and surgical techniques of artificial ligaments are still further needed.      

前交叉韧带侧向刚度在线测量系统研制及其对前交叉韧带重建效果的影响

前交叉韧带重建张力的设置主要依靠外科医生的经验。为提高膝关节恢复治疗中前交叉韧带重建后张力的有效性和适应性,本文建立具有松弛特性的侧向力学测量模型,设计前交叉韧带在线刚度测量系统,提出"术前检测,术中参考"的新方法。本文选取20个绵羊膝关节进行膝关节稳定性测试,分两组进行前外侧入路单束前交叉韧带重建对比实验,第一组手术医生常规流程进行术中检测;第二组使用前交叉韧带在线刚度测量系统在术中进行检测;之后对上述两组进行术后稳定性实验。研究结果表明,该测量系统测量的张力精度为(-2.3±0.04)%,位移误差为(1.5±1.8)%,术后对两组进行前向稳定性、内旋稳定性和外旋稳定性测试,结果均优于术前(P <0.05),但使用该系统的一组更接近术前膝关节测量指标,且与经验丰富的医生对比差异无统计学意义(P> 0.05)。最终,期待本文建立的该系统可以帮助临床医生判断手术过程中的前交叉韧带重建张力,有效提升手术效果。     

Risk factors for anterior cruciate ligament injury in high school and college athletes

The anterior cruciate (ACL) is the most frequently ruptured ligament of the knee. Some authors have suggested that excessive internal tibial rotation concomitant with hyperpronation of the subtalar joint during stance and inherent knee joint laxity may predispose an athlete to knee injury. Over a period of 2 years, we identified 14 ACL-injured football players and eight ACL-injured female basketball players and gymnasts. We matched them by sport, team, position, and level of competition with 22 athletes without history of ACL injury. Measures of navicular drop, calcaneal alignment, and anterior knee joint laxity with a KT-1000 were obtained from the uninjured knee of the ACL-injured athletes and compared with measures obtained from the ACL-noninjured athletes. ACL-injured athletes had greater amounts of navicular drop, suggesting greater subtalar pronation and greater anterior knee joint laxity. Discriminant analysis and multiple regression indicated that these variables correctly predicted injury status for 87.5% of the females and for 70.5% of all cases. These results suggest that the more an athlete pronates and the greater the anterior knee joint laxity, the greater the association with ACL injury.     

Knee stiffness following anterior cruciate ligament reconstruction: The incidence and associated factors of knee stiffness following anterior cruciate ligament reconstruction

We reviewed 100 patients retrospectively following primary ACL reconstruction with quadruple hamstring autografts to evaluate the incidence and factors associated with postoperative stiffness. Stiffness was defined as any loss of motion using the contra-lateral leg as a control. The median delay between injury and operation was 15 months.The incidence of stiffness was 12% at 6 months post-reconstruction. Both incomplete attendance at physiotherapy (p < 0.005) and previous knee surgery (p < 0.005) were the strongest predictors of the stiffness. Anterior knee pain was also associated with the stiffness (p < 0.029). Factors that failed to show a significant association with the stiffness included associated MCL sprain at injury (p = 0.32), post-injury stiffness (p = 1.00) and concomitant menisectomy at reconstruction (p = 0.54). Timing of surgery also did not appear to influence the onset of stiffness (median delays: 29 months for stiff patients; 14 months for non-stiff patients). The rate of stiffness fell to 5% at 12 months postreconstruction, without operative intervention.     

Biomechanical characteristics of the knee joint in female athletes during tasks associated with anterior cruciate ligament injury

This study was designed to compare biomechanical characteristics of the knee joint for several athletic tasks to elucidate their effects and to examine what tasks pose a risk for ACL injury.Three athletic tasks were performed by 24 female athletes: single-limb landing, plant and cutting, and both-limb jump landing. Angular displacements of flexion/extension, abduction/adduction, and external/internal tibial rotation were calculated. Angular excursion and the rate of excursion of abduction and internal tibial rotation were also calculated.During plant and cutting, from foot contact, subjects rotated the tibia more rapidly and to a greater degree toward internal tibial rotation. Moreover, excursion of knee abduction is greater than that during single-limb landing. During both-limb jump landing, the knee flexion at foot contact was greater than for either single-limb landing or plant and cutting; peak knee abduction was greater than for either single-limb landing or plant and cutting.In plant and cutting, the risk of ACL injury is increased by greater excursion and more rapid knee abduction than that which occurs in single-limb landing, in addition to greater internal tibial rotation. Although single-limb tasks apparently pose a greater risk for ACL injury than bilateral landings, both-limb landing with greater knee abduction might also risk ACL injury.     

Effect of wearing a knee brace or sleeve on the knee joint and anterior cruciate ligament force during drop jumps: A clinical intervention study

Background

Knee braces are considered to be extremely useful tools in reducing the shear force of knee joints for non-contact anterior cruciate ligament (ACL) injury prevention. However, the effectiveness of sports knee braces and sleeves remains to be identified. Therefore, the purpose of this study was to evaluate the effectiveness of wearing commercialized sports knee braces and sleeves on knee kinematics, kinetics, and ACL force during drop jumps using musculoskeletal modeling analysis.

Arthroscopic anterior cruciate ligament repair for proximal anterior cruciate ligament tears in skeletally immature patients: Surgical technique and preliminary results

Background

Anterior cruciate ligament (ACL) tears in children are increasingly common and present difficult treatment decisions due to the risk of growth disturbance. Although open primary ACL repair was abandoned in the historical literature, recent studies have suggested that there is a role for arthroscopic primary repair in patients with proximal tears.

Rate and risk of anterior cruciate ligament injury among sportswomen in Slovenia

Context:

Anterior cruciate ligament (ACL)-injury rate is greater among female athletes than among male athletes.

Objective:

To investigate the rate and risk of ACL injury among Slovenian sportswomen playing professional basketball, team handball, or volleyball.

Design:

Prospective cohort study.

Setting:

The Slovenian National Organizations of basketball, team handball, and volleyball.

Patients or Other Participants:

During the 2003–2004 season, we prospectively followed 585 Slovenian sportswomen registered in the Slovenian National Organizations of basketball, team handball, and volleyball.

Main Outcome Measure(s):

We asked sportswomen and coaches to document the occurrence of every significant traumatic knee injury requiring medical attention. Injury rate and injury risk were calculated for sportswomen in each sport group. To calculate injury rate, we estimated the average exposure of each sportswoman during the research period.

Results:

During the 2003–2004 season, 585 Slovenian sportswomen sustained 12 ACL injuries. The ACL-injury risk was different in athletes participating in the various sports, with basketball players having the greatest ACL-injury risk and volleyball players having the lowest ACL-injury risk (P  =  .04). The risk of ACL injury among Slovenian sportswomen was 2.1 per 100 athletes (95% confidence interval  =  0.9, 3.2), whereas the rate of ACL injury was 0.037 per 1000 exposure hours (95% confidence interval  =  0.016, 0.06).

Conclusions:

Overall differences in injury risk were found among sports, but no differences were noted among divisions within sports. No differences for injury rate were observed between or within sports. The rate and risk of ACL injury among Slovenian sportswomen are high, with basketball players having the greatest ACL-injury risk.