Abstract Anterior Cruciate Ligament Research Articles

Testing Limb Symmetry and Asymmetry After Anterior Cruciate Ligament Injury: 4 Considerations to Increase Its Utility

ABSTRACT Anterior cruciate ligament (ACL) injury occurs frequently in sport and surgical reconstruction is often recommended to restore knee joint stability. To guide rehabilitation and determine return to sport readiness, practitioners have used a long-standing practice of calculating the limb symmetry index (LSI) in various functional, biomechanical, and strength tests to compare the injured limb with the noninjured contralateral limb. However, the evidence in support of the LSI calculation to quantify rehabilitation status and return to sport readiness is mixed. We synthesize scientific literature on the LSI calculation and discuss potential reasons for the mixed evidence and limitations. We present 4 considerations to improve the utility of the LSI calculation including (a): the importance of establishing the right benchmark of recovery such as the preinjury contralateral limb or a sport-specific noninjured control benchmark; (b) strategies to manage the high variation in movement asymmetry calculations and the importance of quantifying the intrasubject variability for the component parts of the LSI; (c) the evidence for assessing the movement strategy alongside performance when using the LSI; and (d) how a sport-specific envelope of function can be used to inform post-ACL injury testing that incorporates the LSI.

Concurrent Validity of Movement Screening Criteria Designed to Identify Injury Risk Factors in Adolescent Female Volleyball Players.

Anterior cruciate ligament (ACL) injuries in female adolescent athletes occur at disproportionately high levels compared to their male counterparts. However, limited prospective data exist on the validity of low-cost screening tools that can proactively identify ACL injury risk, specifically for female athletes. The purpose of this study was to assess the concurrent validity of a three-task injury risk factor assessment by comparing visually derived outcome scores from two-dimensional (2D) video data with dichotomized three-dimensional (3D) biomechanical variables collected using motion capture technology. A total of 41 female club volleyball athletes (14.7 ± 1.4 years) were tested and asked to perform three tasks: double-leg vertical jump (DLVJ), single-leg squat (SLS), and single-leg drop landing (SLDL). One rater was trained on the scoring criteria for the 2D data and independently scored one forward-facing and one side-facing video for each task. Risk factors identified included poor knee position, lateral trunk lean, and excessive trunk flexion/extension. In addition, 3D joint angles were calculated for the trunk and knee in the sagittal and frontal planes and converted to dichotomous variables based on biomechanical thresholds of injury risk. For comparison of 2D and 3D outcomes, percent agreement and Cohen's kappa were calculated for each risk factor individually. Overall, 2D scores were found to exhibit moderate to excellent percent agreement with 3D outcomes for trunk position (69.1–97.1%). Specifically, ipsilateral trunk lean during single-leg tasks exhibited the highest agreement (85.3–88.2%) with moderate reliability (κ = 0.452–0.465). In addition, moderate to substantial reliability was found for trunk flexion during double-leg tasks (κ = 0.521–0.653); however, an evaluation of single-leg tasks resulted in only fair reliability (κ = 0.354). Furthermore, 2D scores were not successful in identifying poor knee position as percent agreement fell below 50% for both the single-leg tasks and averaged 60% agreement across both the phases of the DLVJ. Kappa coefficients further emphasized these trends indicating no to slight concurrent validity (κ = −0.047–0.167) across tasks. Overall, these findings emphasize the potential for valid, low-cost screening tools that can identify high-risk movement patterns. Further study is needed to develop improved assessment guidelines that may be employed through visual assessment in sports environments.

Evaluation of anterior cruciate ligament surgical reconstruction through finite element analysis

Anterior cruciate ligament (ACL) tear is one of the most common knee injuries. The ACL reconstruction surgery aims to restore healthy knee function by replacing the injured ligament with a graft. Proper selection of the optimal surgery parameters is a complex task. To this end, we developed an automated modeling framework that accepts subject-specific geometries and produces finite element knee models incorporating different surgical techniques. Initially, we developed a reference model of the intact knee, validated with data provided by the Open Knee(s) project. This helped us evaluate the effectiveness of estimating ligament stiffness directly from MRI. Next, we performed a plethora of “what-if” simulations, comparing responses with the reference model. We found that (a) increasing graft pretension and radius reduces relative knee displacement, (b) the correlation of graft radius and tension should not be neglected, (c) graft fixation angle of 20^{circ } can reduce knee laxity, and (d) single-versus double-bundle techniques demonstrate comparable performance in restraining knee translation. In most cases, these findings confirm reported values from comparative clinical studies. The numerical models are made publicly available, allowing for experimental reuse and lowering the barriers for meta-studies. The modeling approach proposed here can complement orthopedic surgeons in their decision-making.

Leveraging explainable machine learning to identify gait biomechanical parameters associated with anterior cruciate ligament injury

Anterior cruciate ligament (ACL) deficient and reconstructed knees display altered biomechanics during gait. Identifying significant gait changes is important for understanding normal and ACL function and is typically performed by statistical approaches. This paper focuses on the development of an explainable machine learning (ML) empowered methodology to: (i) identify important gait kinematic, kinetic parameters and quantify their contribution in the diagnosis of ACL injury and (ii) investigate the differences in sagittal plane kinematics and kinetics of the gait cycle between ACL deficient, ACL reconstructed and healthy individuals. For this aim, an extensive experimental setup was designed in which three-dimensional ground reaction forces and sagittal plane kinematic as well as kinetic parameters were collected from 151 subjects. The effectiveness of the proposed methodology was evaluated using a comparative analysis with eight well-known classifiers. Support Vector Machines were proved to be the best performing model (accuracy of 94.95%) on a group of 21 selected biomechanical parameters. Neural Networks accomplished the second best performance (92.89%). A state-of-the-art explainability analysis based on SHapley Additive exPlanations (SHAP) and conventional statistical analysis were then employed to quantify the contribution of the input biomechanical parameters in the diagnosis of ACL injury. Features, that would have been neglected by the traditional statistical analysis, were identified as contributing parameters having significant impact on the ML model’s output for ACL injury during gait.

Measurement of Medial Tibial Eminence Dimensions for the Clinical Evaluation of ACL-Injured Knees: A Comparison between CT and MRI.

Anterior cruciate ligament (ACL) injuries commonly lead to translational and rotational tibiofemoral instability. The morphology of the medial tibial eminence (MTE) has received increased attention regarding its role in tibiofemoral stability in ACL-injured knees. Therefore, quantification of MTE dimensions on clinical imaging may help clinicians predict knee stability after ACL injury. Although magnetic resonance imaging (MRI) is routinely obtained in patients with ACL injuries, whether the dimensions of the MTE can be accurate quantified on MRI is unknown. The purpose of this study was to assess the degree of correlation between measurements of MTE height and width on computed tomography (CT) versus MRI. An institutional picture archiving and communication system imaging database was used to identify patients aged between 15 and 60 years who received concurrent MRI and CT of the same knee within a 1-year interval. Knees with significant arthrosis, deformity, intraarticular fracture, or hardware-related artifact that obscured visualization of the MTE were excluded. Mean differences and interstudy agreement between CT and MRI MTE measurements were compared using concordance correlation coefficient (r c) and Bland-Altman analysis. A total of 41 knees in 38 patients (mean age, 37 years; 82% male) were analyzed. Interrater reliability for CT and MRI measurements was high (intraclass correlation coefficient = 0.740-0.954). On coronal CT and MRI, mean MTE height measurements were 10.4 ± 1.9 and 10.4 ± 1.8 mm, respectively; mean MTE width measurements were 14.6 ± 3.6 and 14.2 ± 3.0 mm, respectively. On sagittal CT and MRI, mean MTE height measurements were 11.6 ± 1.7 and 11.7 ± 1.7 mm, respectively; mean MTE width measurements were 36.5 ± 4.8 and 36.2 ± 5.0 mm, respectively. Good agreement was observed between CT and MRI measurements of MTE height and width on coronal and sagittal planes (r c = 0.947-0.969). Measurements of MTE height and width were similar on MRI relative to CT on both coronal and sagittal planes. MRI may be suitable for characterizing the dimensions of the MTE when clinically evaluating patients with ACL injuries, potentially allowing for individualized patient care.

Correlation of Kinematics and Kinetics of Changing Sagittal Plane Body Position during Landing and the Risk of Non-Contact Anterior Cruciate Ligament Injury

Anterior cruciate ligament (ACL) injury is one of the most common knee injuries that negatively affect athletes’ future performance and return to play. The purpose of this study was to examine the correlation of kinematics and kinetics of changing sagittal plane body position during landing and the risk of non-contact ACL injury. Seven university female (age 19.57 ± 0.79 y, height 164.21 ± 8.11 m, weight 60.43 ± 5.99 kg) athletes playing soccer and handball, and with ≥ two years of training volunteered for this research. Three trunk positions: Lean Forward Landing (LFL), Self-selected Landing (SSL), and Upright Landing (URL)—via double/single-leg landing—were captured by a high-speed VICON motion capture system. A 3 × 2 two-way within-subjects ANOVA and Multiple Bonferroni corrected pairwise were used to test for condition (LFL, SSL, URL) and task (single/double-leg) effects (p≤ 0.05). The findings indicated that landing with a deeper knee flexion angle (LFL) would lead to smaller impact forces when compared to upright landing.

The efficacy of platelet rich plasma on anterior cruciate ligament reconstruction: a systematic review and meta-analysis

Anterior cruciate ligament (ACL) rupture is a common musculoskeletal injury, most frequently affecting young and physically active patients. Platelet-rich plasma (PRP) has been widely used in ACL reconstruction to augment the graft healing. However, high-level studies addressing its clinical efficacy could not reach a consensus. In this study, we assess the efficacy of PRP on pain relief, functional improvement along with radiological changes in patients who underwent ACL reconstruction. We performed comprehensive literature search and included 17 RCTs containing 970 participants who underwent ACL reconstruction. The combined data showed significant difference between PRP and control with regard to VAS score (MD: −1.12, 95% CI −1.92, −0.31; P = .007), subjective IKDC score (MD: 6.08, 95% CI 4.39, 7.77; P < .00001) and Lysholm score (MD: 8.49, 95% CI 1.63, 15.36; P = .02) by postoperative 6 months, but only pain reduction was deemed clinically important. At the end of one year’s follow-up, no clinically meaningful improvement in VAS (MD: −0.47, P = .04), subjective IKDC score (MD: 3.99, P = .03), Lysholm score (MD: 2.30, P = .32), objective IKDC score (RR: 1.03, P = .09) and knee joint laxity (MD: 0.17, P = .28) was seen. In terms of radiological findings, about one-third of the studies favored PRP to facilitate the graft healing, improve the harvest site morbidity and prevent tunnel widening. In summary, moderate quality of evidence suggested that PRP could provide short-term but not long-term clinically important pain reduction.

Effect of Cognitive Loading on Single-Leg Jump Landing Biomechanics of Elite Male Volleyball Players

Anterior cruciate ligament (ACL) injury is prevalent during the single-leg jump landing in various sports. The effects of cognitive loading and how it affects risk of ACL injury are not well understood. The purpose of this study is to examine how landing kinetics change in the presence of cognitive loading during a volleyball block. Cognitive loading decreased activations in vastus lateralis and rectus femoris, and increased activation in biceps femoris and medial gastrocnemius muscles. During landing, the first and second peaks of ground reaction forces were 13% and 11% lower under cognitive loading, suggesting that cognitive loading alters landing biomechanics and muscle activations.

Influence of hip strength on acl injury related biomechanics during the cutting maneuver in preadolescent students (practical implication for physical education teachers and sports pedagogues)

Anterior cruciate ligament (ACL) injuries are one of the most serious injuries of the lower limb and can result in a relatively low rate of return to sport and decreased quality of life in later years, as well as to the psychological attitude towards sports among young people. Previous research has investigated the interaction between the hip muscles and knee valgus moments where some studies have concluded that decreased hip abductor and external rotator strength is a risk factor for ACL injury, but no research has been conducted on preadolescent population. Data from 271 students (174 girls), age 9-12 where collected while performing cutting manoeuvre and the isometric maximal voluntary contraction of hip external rotators and abductors. Our results show that no significant correlation where found between the hip strength does not influence the knee VM during the cutting manoeuvre in this age group which is in line with many previous studies conducted on older population.

Lower Extremity Biomechanical Differences Between Female Dancers and Soccer Players

Anterior cruciate ligament (ACL) injury in female athletes is common. Team sport athletes experience more ACL injuries than ballet and modern dancers. Examining biomechanical differences between these two groups may help to explain the discrepancy in ACL injury rates. The purpose of this study was to examine lower extremity kinematic differences between collegiate dancers and National Collegiate Athletic Association Division I soccer athletes during a rebound jump-landing task. Peak hip, knee, and ankle kinematics were collected during a jump-landing task. Results showed more knee flexion and less ankle eversion in the dancers compared to the soccer athletes. Differences in training and strategies used during landing may explain the kinematic differences between groups.

Impact of Physiotherapy rehabilitation program on postoperative ACL tear patient on prognosis leading to maintain consistency in sport

Anterior cruciate ligament (ACL) injury is a devastating injury that occurs at high frequency during involvement in competitive sporting activity. Typical treatment of ACL damage is a reconstruction of the anterior cruciate ligament (ACLR). It is projected that between 50 percent and 60 percent of ACL injured athletes will return to competitive sport. Athletes undergoing ACLR surgery are recommended for comprehensive rehab and preparedness to rebuild knee joint integrity and specific functional criteria to direct the comeback to sport to protect against secondary ACL damage.Patient main concerns were pain, with loss of strength and stability at the knee joint, the clinical findings found that there was a marked decrease in range of motion (ROM), and decreased strength of the quadriceps and the hamstrings.Diagnosis of case was grade 2 ACL tear which was confirmed by the MRI reports.The patient showed a great co-operation during the intervention period and now the subject is able to maintain his consistency in his sport. The outcome measures of physical therapy intervention progressed him in an enhanced athlete with return to his sport.

Evaluation of the Stability of the Subjects with Anterior Cruciate Injuries Reconstruction.

Anterior cruciate ligament (ACL) is the most frequently injured ligament in the knee and is often injured during sport-related activities. ACL injuries influence the abilities of the subjects during standing and walking. Although early surgical intervention is preferred treatment for the majority of knee surgeons, the effect of this approach on postural stability of patients is not fully understood. Therefore, the aim of this study was to determine the difference between stability of ACL-reconstructed subjects before and after surgery. A group of 15 consecutive ACL injured patients participated in this study. Postural stability of the patients was evaluated 1 week before and 6 months after surgery (ACL reconstruction with hamstring autograft). A Kistler force plate was used to evaluate center of pressure (COP) sway during quiet standing. The mean values of the COP parameters were obtained in pre and postsurgery conditions. Paired sample t-test was used to evaluate the difference between the stability parameters of the two conditions. The significant point was set at 0.05. The mean value of path length of COP velocity in mediolateral (ML) direction was 1,485.57 ± 479.42 mm and 2,641.33 ± 996.26 mm before and after surgery, respectively (p-value = 0.01). Although the mean value of COP velocity in anteroposterior and ML directions increased after surgery, the difference was only significant for velocity in ML direction (p-value = 0.049). The results of this study showed that the standing stability of those with ACL reconstruction decreased significantly after ACL reconstruction, which may be due to the effects of the surgery on sensory mechanism of ACL and inability of patients to return to their previous deep sense perception and knee proprioception.

Graft Tunnel Mismatch in Anterior Cruciate Ligament Reconstruction with Bone-Patellar Tendon-Bone Grafts

Anterior cruciate ligament (ACL) reconstruction with bone-patellar tendon-bone (BTB) autograft is a very common surgical procedure for patients with ACL deficient knees; however, itcan be a technically challenging operation with possible intra-operative complications. Graft-tunnel mismatch (GTMM) is a condition in which the ACL BTB autograft does not match the intra-articular and tunnel length.

Biomechanical and Histopathological Analysis on Different Approaches for Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament (ACL) injury is one of the common injuries in sports and vehicle accidents. ACL decreases joint stability, leading to increased incidence of osteoarthritis. Although there are various approaches for the reconstruction of ACL, no consensus has been reached on the safest and most effective method to achieve joint stability. Here we have compared the biomechanical and histopathological outcomes of three different approaches: intra-articular ACL reconstruction, remnant-preserving and re-tensioning and non-remnant-preservation technique, using finite element analysis, histopathologic observation as well as qPCR and western blot analysis. Results of the current study showed no significant differences among the three methods concerning biomechanical, histopathological analysis and mRNA and protein levels of chondrocyte apoptotic markers such as JNK, MMP-1 and SIRT1 (P &gt; 0 05). Those results indicated that remnant preservation techniques such as intra-articular ACL reconstruction and remnant-preserving and re-tensioning are similar in their ability to achieve joint stabilization and prevent chondrocyte regeneration to non-remnantpreservation technique.

Theoretical and Numerical Analysis of Anterior Cruciate Ligament Injury and its Prevention

Anterior cruciate ligament (ACL) injury is one of major risks for most athletes. ACL injury can be caused by many risk factors such as anatomic risk factors, biomechanical risk factors and environmental risk factors. In this article, numerical and theoretical analysis are conducted to investigate biomechanical risk factors. An entire three-dimensional finite element knee model was built based on MRI data. Anterior Tibial Translations (ATT) at different knee flexion angles are simulated by finite element models. In the simulations, more attentions are given to material properties of different knee components and their effects on ACL injury. Mechanical response of ACL during sport activities is highly determined by its viscoelastic properties. Unfortunately, viscoelastic properties of two bundles of ACL will change dramatically even with several hours’ physical aging. As a consequence, ACL will experience mechanical ductile to brittle transition due to daily physical aging. Theory of physical aging from polymer science is, for the first time, introduced to understand ACL injury and its prevention. By analogy to physical aging of amorphous polymer materials, we think physical aging of two bundles of ACL will largely increase risk of ACL injury. Besides, physical aging will also build a heterogeneous stress and strain in ACL due to its natural anatomic structure, which is a large risk for athletes. The specific designed prevention programs for ACL injury such as plyometrics, strengthening and other neuromuscular training exercises [1] are believed to erase physical aging of ACL. ACL with less physical aging is less likely to get injured in sport activities. In this article, a virtual physical aging simulation is built to validate current hypothesis. Erasing physical aging of ACL may provide an accurate and quantitative way to prevent ACL injury.

ANTERIOR CRUCIATE LIGAMENT SECTIONING ALTERS CENTER OF PRESSURE WITHIN THE TIBIOFEMORAL JOINT: AN IN VITRO STUDY

Anterior cruciate ligament (ACL) injuries often lead to secondary injuries, joint degradation, and were linked to osteoarthritis. There is little known about how ACL rupture affects the loading and contact characteristics within the tibiofemoral joint. The objective of this study was to evaluate changes in tibiofemoral joint contact pressure and center of pressure (COP) during dynamic motion before and after ACL sectioning in vitro. Six intact cadaveric knees were manipulated through three full cycles of motion ranging from 30∘ to 120∘ of flexion in a custom-built device. A pressure sensor inserted in the tibiofemoral joint measured contact pressure of the medial and lateral compartments as well as COP characteristics of the whole joint before and after the ACL was sectioned. There was a significant decrease in lateral-compartment peak pressure, medial and lateral mean pressure, and total contact area after the ACL was sectioned. In both intact and ACL deficient knees, a posterior-lateral shift in COP was observed during flexion and a medial-anterior shift when returning to extension. Plotting the COP trajectory through the flexion-extension cycle resulted in a distinct hysteresis curve due to the viscoelastic soft tissue properties. Following sectioning, the COP trajectory had a diminished area compared to the intact condition. The diminished area of contact pressure may be more problematic than the overall magnitude when the integrity of the ACL is compromised. The centralized pressure distribution to a smaller surface area over time may cause focal damage to the cartilage leading to osteoarthritis.

1. Investigating the Link Between Kinematic, Kinetic and Muscular Symmetry in Young Adults 12 or More Months post-ACL Reconstruction

Anterior cruciate ligament (ACL) injury after primary reconstruction and return-to-sport clearance is common. Since research indicates asymmetry as a valid predictor of injury, it is proposed that inter-limb asymmetry following ACL reconstruction contributes to the elevated incidence of re-injury in this population. Current return-to-sport protocol include objective tests such as joint laxity and strength tests, as well as single leg hop and drop landing tests. Since these assessments are based on visual observation, or simple kinematics measurements, it is unclear how visual asymmetry reflects the underlying joint forces and muscular effort responsible for the performance in these tasks. This study aims to assess the asymmetry present at the kinematic, kinetic, and motor control levels to clarify the after-effects of ACL reconstruction. This pilot study will help us appreciate if additional work exploring screening measures as effective tools for predicting ACL injury following primary reconstruction is warranted. Standard techniques will be used to measure the kinematics, joint kinetics and muscle activation during this 25-repetition squat protocol. Correlations will compare the left and right lower limbs for joint angular displacement, joint angular velocity, joint power, vertical ground reaction forces, and muscle activation amplitude.

Study of isokinetic strength training's rehabilitating effects on elite athletes after knee joint ACL reconstruction surgery

Anterior cruciate ligament (ACL) injury is one of the most common knee injuries for most athletes and sports-active people. Arthroscopic reconstruction is the preferred treatment. Rebuilding ACL for the rapid return to pre-injury level movement and function is an important goal for athletes. In this paper, the use of isokinetic strength training methods for athletes after ACL injury rehabilitation effect is reported. Thirty-one knee anterior cruciate ligament reconstruction athletes were divided into two groups and were respectively subjected to 12 weeks' traditional rehabilitation training and isokinetic strength training. It was found that constant strength training of the knee joint could improve the muscle strength of the athletes more quickly which provides better rehabilitation training for the postoperative recovery of athletes to return to the track.

Influence of ground reaction force perturbations on anterior cruciate ligament loading during sidestep cutting

Anterior cruciate ligament (ACL) injury risk is likely increased under unexpected loading conditions. Such situations may arise from mid-air contact with another athlete, or misjudgments in landing height, stride length or surface compliance resulting in an unbalanced landing and unexpected changes in the ground reaction forces (GRFs). The purpose this study was to identify how GRF perturbations influence ACL loading during sidestep cutting. Muscle-actuated simulations of sidestep cutting were generated and analyzed for 20 subjects. Perturbations of 20, 40 and 60% of the nominal value were applied to the posterior, vertical, and medial GRF. Open-loop, forward dynamics simulations were run with no feedback or correction mechanism which allowed deviations from the experimentally measured kinematics as a result of the GRF perturbations. Posterior and vertical GRF perturbations significantly increased ACL loading, although the change was more pronounced with posterior perturbations. These changes were primarily due to the sagittal plane component of ACL loading regardless of perturbation direction. Peak ACL loading occurred almost immediately after initial ground contact, and was thus predicated on initial joint configuration. The results of this study give merit to including knee flexion angle at initial ground contact in the evolving neuromuscular training modalities aimed at preventing non-contact ACL injury.

Prevention of Primary ACL Injuries: A Novel, Innovative Approach

Abstract Anterior cruciate ligament (ACL) injuries are increasing amongst professional and recreational athletes, and creating prevention programs to reduce the occurrence of ACL damages is becoming a necessity. To prevent an ACL tear, it is necessary to comprehend the mechanisms and the risk factors of injury. Biomechanical and clinical studies try to understand these complex mechanisms in order to identify factors that can be improved and to develop training programs to prevent at least non-contact ACL injuries. There are several promising programs, but there are still many questions to answer. This paper analyzes the risk factors for ACL injuries and some aspects of the modern programs developed to decrease the rate of ACL tears.