Anterior cruciate ligament (ACL) injuries significantly impact young athletes, leading to long-term physical, psychological, and socioeconomic consequences. There is an urgent need to develop effective preventive strategies. This scoping review aims to evaluate modifiable and non-modifiable risk factors for ACL injuries and assess existing preventive strategies.

A comprehensive literature search was performed on November 20, 2024, across databases including Embase, PubMed, Web of Science, Google Scholar, and Cochrane Library. Articles published between 2000 and 2024 focusing on ACL injury prevention were included, while editorial content, non-clinical studies, and non-English publications were excluded.

The search yielded 322 articles, narrowing down to 94 after deduplication. After title screening, 46 studies progressed to full review, ultimately leading to the inclusion of 14 relevant manuscripts. Key findings indicate that ACL injuries result from various factors, with female athletes being 2.2 times more susceptible. Genetic predispositions linked to collagen-related SNPs and biomechanical patterns, such as landing techniques and knee positioning, were identified as significant contributors. Effective preventive programs integrated strength training, neuromuscular training, and advanced technology, including wearable devices and video analysis.

The study reinforces the importance of a personalized, multifaceted approach to ACL injury prevention, focusing on risk stratification and optimizing training strategies alongside technological advancements. Implementing these strategies can significantly mitigate the risk of ACL injuries in high-risk populations.

Accurately identifying residual biomechanical deficits following an anterior cruciate ligament injury is critical for effective rehabilitation and safe return to sport. This study aimed to determine which of four jump-landing tasks demonstrated the greatest sensitivity in distinguishing individuals with a history of ACL injury from healthy controls. Forty-three participants formed the ACL (n = 21, 11 females) and the control group (n = 22, 12 females). Three-dimensional motion data (Vicon, 250 Hz) were recorded during a single-leg hop, unilateral countermovement jump, unilateral crossover hop, and medial-rotation hop before and after a fatigue-inducing intervention (single-leg squats and step-ups). Logistic regression models to classify participants were built using 13 lower-body, trunk, and pelvis joint angles at 50 ms after initial ground contact, angular changes in these angles between 50 and 80 ms, and principal components derived from these variables. Classification rates and individual classification outcomes were assessed. The results revealed that no single jump-landing task consistently outperformed others in detecting ACL injury history. Classification outcomes were influenced by fatigue state and analytical approaches. Fatigue was found to enhance classification rates. Combining joint angles with their temporal changes improved classification rates compared to using joint angles alone. However, applying principal component analysis as a preprocessing step did not consistently enhance model performance. Overall, the study demonstrated that jump-landing tasks, combined with a variety of analytical approaches, can effectively detect ACL injury history. Fatigue enhanced classification outcomes, suggesting that it amplifies differences between post-injury and healthy movement characteristics.

Deficits in dynamic postural stability are associated with increased risk of lower limb injuries. Objective dynamic postural stability assessments typically require force plates, which are not commonly available in the clinic. Moreover, these outcomes are not directly related to balance strategies, which hampers clinical interpretation and translation to therapeutic goals. Direct measurements of kinematics can be more suitable in these respects. This study aims to investigate the concurrent validity and responsiveness of trunk angular velocity.

Data from fourteen healthy participants were analyzed using a within-subject design. Participants were standing on one leg on a platform with an embedded force plate that was used to impose mediolateral perturbations to evoke balance responses. To introduce variability within participants, perturbation amplitude and base-of-support width were manipulated. Time-to-stability, mean center of pressure speed and the mean vertical force deviation of the ground reaction force were derived from force plate data and mean trunk angular velocity was obtained from an inertial measurement unit. All outcomes were calculated over a five-second time window after perturbation onset. Multilevel correlations were calculated to assess the concurrent validity of trunk angular velocity. To compare the responsiveness of trunk angular velocity and force plate-based outcomes, effect sizes of a repeated measures ANOVA were used.

Trunk angular velocity correlated strongly with center of pressure speed (r = 0.78) and the vertical force deviation (r = 0.74) and moderately with time-to-stability (r = 0.61). Trunk angular velocity demonstrated the largest effect sizes in the repeated measures ANOVA.

Trunk angular velocity is a promising outcome to use in the clinic. Its concurrent validity and responsiveness are supported by the results of this study.

Ipsilateral second anterior cruciate ligament (ACL) injuries, are more common in males compared to females. An ACL re-rupture can imply both physical and psychological consequences for patients, with reports of lower objective and subjective outcomes after a re-rupture compared with primary ACL injury. This study aimed to explore young men's experiences of their first ACL injury, reconstruction and subsequent ACL re-rupture.

Eighteen males (19-33 years old) were interviewed with semi-structured interviews, which were recorded, transcribed, and analysed with qualitative content analysis, based on the method described by Graneheim and Lundman. The method involves a systematic process where three authors were involved. The interview transcripts were red multiple times, meaning units were identified, and codes were generated. These codes were then grouped into sub-categories and further sorted into main categories. Results were presented as a positive or negative psychological response through the four domains (cognition, affect, behaviour, and outcome) used in the model by Weise-Bjornsdal´s: cognition, affect, behavior and outcome, i.e., "the model of psychological response".

Fifteen main categories and 34 sub-categories emerged the data, presented as 2 timelines between the "first ACL injury" to "ACL re-rupture" and from "ACL re-rupture" and onwards. Positive emotions with the first ACL injury were high motivation to return to sport (RTS), great trust in the process of recovery and great support system from friends and family. Negatively, patients expressed shattered sport dreams, physical and mental trauma leading to experiences of identity loss, and a sense of loneliness. Positive experiences with the ACL re-rupture were humbleness and joy for other shapes of sport participation, such as coaching, and for activity to be joyful rather than performance connected. Negatively, patients searched for answers, e.g., whether surgery and rehabilitation were performed appropriately the first time, or whether the outcome could have been different with another autograft or if RTS was delayed.

After the first ACL injury, patients predominantly faced negative emotions that questioned their self-image. Despite several challenges, motivation remained high as the goal was RTS. Upon the ACL re-rupture, patients experienced a shift in perspective with sport participation and a door opening to new opportunities in life e.g., coaching. This unexpected turn of events became a catalyst for exploration of different aspects of emotions with the ACL journey, which included broader horizons beyond confines of athleticism.

Not applicable.

Aim of this study was to report the long-term outcomes of a cohort of patients treated with a selective bundle ACL reconstruction of a partial tear evaluating functional results as well as failure and satisfaction rates. The hypothesis was that good clinical results, high satisfaction and low failure rates could be obtained.

Patients treated with selective bundle ACL reconstruction between September 2008 and September 2011 were included. Functional assessment was performed with the objective International Knee Documentation Committee (IKDC) ligament evaluation form, the Lysholm knee scale and the Tegner activity level scale.

Fifty-two patients were available for follow up. The average follow-up period was 14 years (13-16). Twenty-two had anteromedial bundle tears and 30 had posterolateral bundle tears. On average, a significant improvement was obtained from pre-surgery to last follow-up for Lysholm (pre-surg 64.1 ± 5.1; last follow-up 95.8 ± 6.2; p < 0.001) and subjective IKDC (pre-surg 56.5 ± 7.5; last-follow-up 91.6 ± 9.8; p < 0.001) scores. 3 patients underwent ACL revision surgery in the first-year post-surgery and 3 patients reported subjective instability accounting for a cumulative failure rate of 11.5% (6/52) and 7.7% of dissatisfied patients (4/52).

Selective bundle ACL reconstruction for partial ACL tears enable good to excellent results with high satisfaction (92.3%) and low revision rates (5.7%) at long-term follow-up (minimum 13 years, mean 14 years).

Standard care for anterior cruciate ligament (ACL) injuries often includes surgical reconstruction of the ACL. However, two randomized controlled trials (RCT) concluded that conservative treatment does not result in inferior clinical outcomes compared to immediate ACL reconstruction. More research is needed to verify these results and to assess whether patient-specific parameters can predict whether a patient would benefit from immediate surgery or conservative treatment. However, before running such an RCT, we performed this pilot study to assess the feasibility of recruiting patients for such an RCT.

This is a pragmatic, multicenter, randomized, controlled pilot trial with two parallel groups funded by the Belgian Health Care Knowledge Centre (KCE trials). Patients with an acute ACL injury were recruited from two Belgian hospitals. They were randomized to either conservative treatment (e.g., rehabilitation with optional delayed surgery in case of persistent instability) or immediate surgery (< 12 weeks post-injury). The primary aim of this pilot study was to assess the feasibility of participant recruitment. Furthermore, we evaluated adherence to the protocol and the allocated treatment arm and the feasibility of recruiting a representative sample of ACL patients.

Out of the initial 70 screened patients, 29 were included in the pilot study, 15 were randomized in the conservative treatment group, and 14 were in the surgical treatment group. This yielded a recruitment rate of 41%. However, the investigators could not screen many potential patients due to inadequate referrals within the recruiting hospitals. Seven cross-overs were observed between the treatment arms: 3 patients who were assigned to the conservative treatment group insisted on immediate surgery, while four patients allocated to immediate surgery chose not to undergo surgery. Of the initial 29 patients, 5 dropped out after randomization. The recruited sample confirmed the typically young and physically active sample of ACL patients.

This pilot study confirmed the challenging recruitment process for an RCT that compares a surgical and a non-surgical treatment option. While encountering substantial recruitment challenges, our pilot study revealed that transitioning to a full-scale RCT is feasible, with some essential modifications. Key adjustments encompassed augmenting the number of participating sites, optimizing patient recruitment processes, and extending the recruitment period. Furthermore, this study showed a high completion rate, affirming the feasibility of the study protocol. However, there was a high cross-over rate (7/29 patients) between treatment arms. This should be avoided when progressing to the full trial. The recruited sample reflects a young and active population, which represents the ACL population well.

ClinicalTrials.gov (NCT04408690) on 25/05/2020.

Identifying patients at high risk for failure of primary anterior cruciate ligament reconstruction (ACLR) on the basis of preoperative magnetic resonance imaging (MRI) measurements has received considerable attention. In this study, we aimed to identify potential risk factors for primary ACLR failure from preoperative MRI measurements and to determine optimal cutoff values for clinical relevance.

Retrospective review and follow-up were conducted in this nested case-control study of patients who underwent primary single-bundle ACLR using hamstring tendon autograft at our institution from August 2016 to January 2018. The failed ACLR group included 72 patients with graft failure within 5 years after primary ACLR, while the control group included 144 propensity score-matched patients without failure during the 5-year follow-up period. Preoperative MRI measurements were compared between the 2 groups. Receiver operating characteristic (ROC) curve analyses were conducted to determine the optimal cutoff values for the significant risk factors. Odds ratios (ORs) were calculated, and survival analyses were performed to evaluate the clinical relevance of the determined thresholds.

A greater lateral femoral condyle ratio (LFCR) (p = 0.0076), greater posterior tibial slope in the lateral compartment (LPTS) (p = 0.0002), and greater internal rotational tibial subluxation (IRTS) (p < 0.0001) were identified in the failed ACLR group compared with the control group. ROC analyses showed that the optimal cutoff values for IRTS and LPTS were 5.8 mm (area under the curve [AUC], 0.708; specificity, 89.6%; sensitivity, 41.7%) and 8.5° (AUC, 0.655; specificity, 71.5%; sensitivity, 62.5%), respectively. Patients who met the IRTS (OR, 6.14; hazard ratio [HR], 3.87) or LPTS threshold (OR, 4.19; HR, 3.07) demonstrated a higher risk of primary ACLR failure and were significantly more likely to experience ACLR failure in a shorter time period.

Preoperative MRI measurements of increased IRTS, LPTS, and LFCR were identified as risk factors for primary ACLR failure. The optimal cutoff value of 5.8 mm for IRTS and 8.5° for LPTS could be valuable in the perioperative management of primary ACLR.

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Anterior cruciate ligament (ACL) rupture is thought to alter the way in which the brain receives and processes information, affecting body movements. Although alterations in brain activity after ACL rupture have been described, these are limited to time points more than 6 months after rupture. Therefore, this pilot study aims to investigate cortical activity during an active knee joint position sense (JPS) test within the first 4 months after ACL reconstruction.

Twelve participants with ACL reconstruction (nine males; age 25.3 ± 6.4 years; height 173.6 ± 8.0 cm; mass 71.1 ± 9.1 kg) and 12 matched healthy controls (nine males; age 28.8 ± 9.7 years; height 174.5 ± 9.7 cm; mass 72.7 ± 12.7 kg) performed an active knee JPS test in an open kinetic chain with a starting angle of 90° knee flexion and a target angle of 50°. Absolute angular error was measured with an electrogoniometer. Cortical activity was simultaneously recorded with dry electroencephalography. Participants with ACL reconstruction were measured at 5-8 weeks postoperative (M1) and 12-16 weeks postoperative (M2), the control group once. Power spectra for the frequencies, theta (4.75-6.75 Hz), alpha-1 (7.0-9.5 Hz) and alpha-2 (9.75-12.5 Hz) for frontal, central and parietal regions of interest were calculated.

Participants with ACL reconstruction exhibited significantly higher central theta power during JPS testing with their uninvolved leg at M1 compared with M2 (adjusted P = 0.01; rank epsilon squared = 0.39). No other comparisons yielded statistically significant differences.

The results cautiously support current evidence on cortical alterations following ACL reconstruction. A larger sample size and more measurement time points may provide further insight into possible alterations in the early postoperative period.

Anterior cruciate ligament (ACL) injuries are common among athletes and significantly impact their knee stability and performance. Surgical reconstruction is the standard treatment. The modified transtibial technique has emerged as a promising surgical approach for optimal graft positioning and complication reduction.

A retrospective study of athletes who underwent primary ACL reconstruction with the modified transtibial technique was conducted. Clinical outcomes were evaluated using the Lysholm and International Knee Documentation Committee (IKDC) subjective scores and objective knee stability assessments. Return-to-sport rates and associated factors were analyzed.

Forty-four athletes were included (thirty-seven males, seven females; mean age 21.2 ± 5.0 years). At mean follow-up of 27.0 ± 12.2 months, significant improvements in the Lysholm and IKDC subjective scores were observed. Overall, 88.2% of athletes returned to sports, and 65.9% achieved their pre-injury levels. Return to pre-injury level was defined as regaining the same type, intensity, and frequency of sport participation as before the injury occurred. Professional athletes showed significantly higher return-to-pre-injury-sport rates (79.3%) than recreational athletes (40.0%, p = 0.0091). Concomitant meniscus injuries negatively impacted return-to-sport rates (92.9% versus 66.7%, p = 0.0397). The overall failure rate was 4.6% (2/44; 95% confidence level [CI]: 0.6-15.5%) with two cases of graft insufficiency or re-rupture.

ACL reconstruction with the modified transtibial technique provides favorable clinical outcomes, high return-to-sport rates, and low failure rates, particularly among professional athletes. Meniscus preservation is crucial for optimizing post-operative recovery. Future research should focus on long-term outcomes and comparative studies with other ACL reconstruction techniques.

In Australia, few people with acute anterior cruciate ligament (ACL) rupture are managed with rehabilitation alone despite clinical trials demonstrating similar outcomes to ACL reconstruction (ACLR). The reasons for the low uptake of rehabilitation alone for the treatment of acute ACL rupture in Australia are unclear.

The objectives of this study were to evaluate physical therapists' beliefs and the information they provide to patients about treatment options for ACL rupture, and to explore ACL rupture treatment decision-making from the perspective of physical therapists.

The design was a mixed-methods convergent parallel design comprising an Australia-wide survey (n = 246) and semi-structured interviews (n = 10).

Participants included physical therapists who manage people with ACL rupture in Australia.

The survey contained 41 items that assessed demographics, treatment of ACL rupture, referral pathways, treatment beliefs, and the information provided to patients with ACL rupture.

Physical therapists' beliefs about treatment options varied and did not always reflect the information they provided to patients. Although 60% agreed that ACLR and rehabilitation-alone result in similar outcomes on average, only 37% reported regularly informing patients about this. To return to pivoting/contact sport, 23% believed that ACLR was required and 79% informed patients that ACLR was the best treatment to do so. Physical therapists felt that rehabilitation-alone is underutilized as a treatment for ACL rupture. Physical therapists encountered barriers to offering and providing rehabilitation-alone for ACL rupture, reflected in 7 qualitative themes: preference for surgery reflecting societal beliefs; more weight given to surgeon's opinion; unbalanced information from surgeon; referral pathways; uncertain recovery timeline; beliefs about treatment suitability; and knowledge and experience.

Physical therapists had mixed beliefs about treatment options and the information provided to patients was not always evidence based. Physical therapists felt that nonsurgical management was underutilized, and experienced barriers to offering and providing non-surgical management of ACL rupture in clinical practice.

Informed decision-making can only occur if accurate, evidence-based information about ACL rupture treatment options is provided to patients. These findings may be used to guide professional development for physical therapists and inform strategies to improve evidence uptake by physical therapists.

Social determinants of health (SDOH) contribute to delays in access to care and inferior outcomes following anterior cruciate ligament (ACL) reconstruction. The interplay between multiple SDOH factors has not been investigated in children and adolescents during rehabilitation.

To assess the relationships between SDOH variables, including demographics, singular surrogate indicators and multivariate indices, and quadriceps strength recovery at time of return-to-play testing following pediatric ACL reconstruction.

Retrospective Cross-Sectional Study.

Patients who underwent primary ACL reconstruction at a single pediatric tertiary-care center completed a standardized return-to-play battery of tests six months post-operatively. The associations and interactions between SDOH variables and knee extension peak torque limb symmetry index (LSI), obtained during isokinetic testing at 60 °/s, were explored statistically with both univariate and multivariate analyses.

Data on 259 White or Black/African American patients (43.2% female, mean age 15.3 ± 2.0 years) were utilized for analyses. Although several SDOH variables were significantly associated with knee extension peak torque LSI in univariate regression analyses, only sex, F (1, 253) = 11.15, p = 0.001, race, F (1, 253) = 12.06, p < 0.001 and their interaction, F (1, 253) = 6.53 , p = 0.011, remained statistically significant when entered in the final general linear model after controlling for age and graft type. Adjusted means (standard errors) for knee extension peak torque LSI were 74.6% (1.9) for White males, 72.8% (2.1) for White females, 72.5% (1.9) for Black or African American males, and 60.5% (2.2) for Black or African American females.

Black or African American females demonstrated inferior quadriceps strength recovery six months following pediatric ACL reconstruction. The development of targeted interventions and multicomponent initiatives to reduce combined racial and sex disparities following pediatric ACL reconstruction are warranted to close the gap in pediatric orthopedic care.

Level 3.

Anterior cruciate ligament (ACL) injuries are common in female basketball players, who have a 2 to 3 times higher risk for an ACL injury than their male counterparts. Improving our understanding of the situations and biomechanics that result in an ACL injury in basketball players may support the design of more effective programs to mitigate the injury risk.

To describe the injury mechanisms, situational patterns, and biomechanics of ACL injuries during matches in professional female basketball players.

Case series; Level of evidence, 4.

A total of 105 ACL injuries in professional female European basketball leagues from the 2018 to 2023 seasons were identified. There were 41 (39%) injury videos analyzed for injury mechanisms and situational patterns, while biomechanical analysis was possible in 33 cases. There were 3 independent reviewers who rated each video. Data according to player position, phase of the match, and location on the court were also evaluated (n = 41). Analysis regarding neurocognitive perturbation was assessed in 41 cases (100%).

Most injuries (n = 28 [68%]) occurred during offensive possession. Indirect contact injuries were more prevalent (n = 23 [56%]) than noncontact injuries (n = 18 [44%]). Overall, 3 main situational patterns constituted 95% of injuries: offensive cut (n = 20 [49%]), defensive cut (n = 12 [29%]), and landing from a jump (n = 7 [17%]). Injuries involving a knee-dominant pattern with valgus were identified in 64% of cases. Injuries were evenly distributed between the first (53%) and second (47%) halves of a game. Half (50%) occurred within the first 10 minutes of effective playing time, and the most frequent months of injury were October and November (44%; early season). Nearly half (46%) of the injuries occurred in small forwards, with 59% of injuries occurring in zone 5. Neurocognitive errors were seen in 56% of injuries, while 92% of defensive injuries showed signs of neurocognitive errors.

ACL injuries in professional female basketball players were caused by indirect contact or noncontact, involving offensive and defensive cuts as well as landing from a jump. Biomechanical analysis confirmed a multiplanar mechanism with a knee-dominant pattern and valgus. Most injuries occurred early in the season and within the first 20 effective minutes played (89%), making accumulated fatigue an unlikely risk factor for ACL injuries in basketball players.

To compare outcomes after anterior cruciate ligament reconstruction (ACLR) with bone marrow aspirate concentrate (BMAC), demineralized bone matrix (DBM), and suture tape augmentation (STA) versus ACLR without biological augmentation or STA.

We performed a prospective randomized controlled trial at a single institution to compare ACLR with BMAC, DBM, and STA (group A) versus ACLR without biological augmentation or STA (group NA). The study sought to include 100 patients. Skeletally mature patients younger than 25 years received quadriceps tendon autograft, whereas patients aged 25 years or older underwent allograft ACLR with an all-inside technique. Patients with concomitant meniscal pathologies were included. The primary outcomes compared were range of motion (ROM), limb symmetry, and patient-reported outcomes. Secondary outcomes included radiographic outcomes and surgical complications. Univariate and mixed-model regression analyses were used to compare outcomes.

Fifty-nine patients were included (29 patients in group A [11 female patients, 38%] and 30 patients in group NA [15 female patients, 50%]). Early ROM at 6 weeks (125° of flexion vs 109° of flexion, P < .0001) and limb symmetry at 12 weeks (80.6% vs 36.7% [delta, 43.9%], P < .001) were significantly improved in group A. At 2 years, International Knee Documentation Committee scores were similar (91.1 ± 12.7 vs 85.3 ± 10.8, P = .109). Quality-of-life subscores of the Knee Injury and Osteoarthritis Outcome Score were significantly enhanced in group A (85.2 ± 20.9 vs 72.1 ± 20.4, P = .042). In 22 patients (12 in group A and 10 in group NA), computed tomography scans were obtained at 6 months to compare bone tunnel healing. Overall, the mean increase in bone tunnel diameter was significantly smaller in group A than in group NA. No difference in graft rerupture or reoperation rate was observed. Reoperations were performed for stiffness in 7 of 59 patients (11.9%) (3 [10%] in group A vs 4 [13%] in group NA; P > .999).

There were no differences in International Knee Documentation Committee scores between groups at 2-year follow-up. Functional outcomes including early ROM and limb symmetry were significantly improved in patients who received ACLR with BMAC, DBM, and STA.

Level II, randomized controlled trial.

To describe knee reinjuries and surgeries within 2 years after an acute anterior cruciate ligament (ACL) injury, in patients treated with or without ACL reconstruction (ACLR).

Two years follow-up of 275 patients (52% females, mean age 25.2 [SD 7.0] years) about knee reinjuries and surgeries were analysed from the prospective NACOX cohort study, aiming to describe recovery after an acute ACL injury treated according to clinical routine. Knee reinjury was defined as increase or new symptoms due to new trauma. At 2 years after injury, 169 (61%) had undergone an ACLR. Results are presented with descriptive statistics and risk ratios (RR).

Thirty-two patients sustained reinjuries within 2 years; 6 in the non-ACLR group, and 26 in the ACLR group (7 before and 19 after ACLR). Twelve patients in the ACLR group sustained a graft rupture and three did an ACL revision. Patients with non-ACLR, aged 21-25 years, had a 5.9-fold higher risk for reinjury than those aged 15-20 years (RR 5.9 [1.3-26.9]; p = 0.012). Twenty-four patients had surgery in the non-ACLR group and 36 patients in the ACLR group (excluding primary ACLR), where six were before ACLR and 30 were after ACLR.

Twelve percent sustained a knee reinjury and 21% underwent knee surgery within 2 years after the index ACL injury. There was a higher reinjury incidence in the ACLR group, but no difference in incidence of surgeries. Thus, ACLR did not reduce the risk of traumatic reinjuries or surgeries, which is important for treatment decision considerations.

Level I.

To analyze if immediate visual and verbal feedback influenced landing mechanics during single and dual-task conditions in recreationally active females with a history of anterior cruciate ligament reconstruction (ACLr) compared to healthy controls.

Cross-sectional cohort study.

Motion Laboratory.

33 college-aged females with two to five years status post-ACLr and 33 matched health controls.

30 Drop landings were performed over one single session with immediate post-trial feedback followed by a retention trial on peak vGRF and symmetry.

Vertical ground reaction forces (vGRFs) during drop landing from a 50-cm platform and loading rate (LR) normalized to body weight.

For peak vGRF, there was a time effect from baseline, post-test, and transfer task trials. Based on baseline, post-test, and transfer tasks, there was a significant group-by-time interaction between the ACLr and a healthy group. For peak vGRF asymmetry, there was no time effect from baseline, post-test, and transfer task trials. There was a significant group effect for peak vGRF asymmetry. Total LR did not show a time effect from baseline, post-test, and transfer task. The ACLr group demonstrated higher LR compared to the health group.

Results demonstrated a reduction in peak vGRF and asymmetry in vGRF during drop landings with the inclusion of augmented feedback. The ACLr group demonstrated higher LR than the control group. Rehabilitation specialists may be able to incorporate targeted feedback as an intervention to help resolve landing asymmetries following ACLr.

There remains a pressing need to enhance sports rehabilitation practices due to several ongoing challenges like increasing re-injury rates. By encouraging practitioners to begin with the end in mind, a backward design approach can help create more comprehensive and sport-specific rehabilitation programs that better support athletes' return-to-sport outcomes. However, there is a lack of clear and actionable guidance for applying backward design approaches in more advanced scenarios like when rehabilitating complex injuries in highly dynamic and unpredictable sporting contexts. Through three highly prevalent use cases, this article will address this critical gap by highlighting the modularity of backward design approaches, and offer practical and step-by-step strategies for practitioners looking for solutions in these contexts.

Anterior cruciate ligament injury rates are high and often associated with change-of-direction movements. Analysis of youth movement patterns is critical for avoiding injury and foot progression angle affects lower extremity kinematics during cutting movements. Knee abduction and hip adduction are known predictors of anterior cruciate ligament injury. The relationship between foot progression angle and lower extremity biomechanics lacks exploration in youth athletes following anterior cruciate ligament reconstruction. This study aimed to assess the relationship between foot progression angle at max knee flexion, and mechanics predictive of anterior cruciate ligament injury during a change-of-direction task in youth athletes following anterior cruciate ligament reconstruction.

Thirty-four participants (12 m, 15.0 ± 2.5 years) who previously underwent anterior cruciate ligament reconstruction participated in the study. Participants performed a 45-degree run cut task on both affected and unaffected limbs. Trunk and lower extremity biomechanics were collected using 3D motion capture and force plates.

Moderate correlations were observed on the affected limb for trunk, pelvis, hip, knee, and ankle angles, as well as ankle moments (r = -0.34-0.52). On the unaffected limb, moderate correlations were seen in pelvis, hip, and ankle angles (r = 0.41-0.44). Significant differences exist between limbs for pelvis, hip and knee angles, as well as knee moments (p ≤ 0.038).

Youth athletes appear to exhibit cutting movement patterns following anterior cruciate ligament reconstruction that may increase their risk of anterior cruciate ligament reinjury. Foot progression angle is a potential component of cutting tasks that clinicians and coaches can use to reduce an athlete's injury risk.

No consensus is obtained regarding the effects of remnant-preserving ACL reconstruction on long-term clinical and proprioceptive outcomes. This study aimed to compare proprioceptive and clinical outcomes of the knee joint after ACL reconstruction with two different lengths of preserved remnant tissue.

This study included 61 patients who underwent single-bundle ACL reconstruction with remnant preservation method using hamstring autograft, divided into two groups according to the length of the remnant tissue. Group ≤33% included subjects with equal and less than 1/3 of the remnant preserved (n = 30) and group >33% included subjects with more than 1/3 of the remnant preserved (n = 31). Proprioception was evaluated at 20°, 50°, and 70° knee angles. Clinical outcome measures included Tegner activity scale, Lysholm knee score, single-leg-hop test, and muscle strength of quadriceps femoris and hamstring muscles which was evaluated using Biodex dynamometer. Anterior laxity was determined with a KT2000 arthrometer. A statistical comparison of the assessments was performed.

The mean follow-up time after surgery were 28.33 and 33.67 months for group ≤33% and >33%, respectively. No significant differences were detected for Lysholm and Tegner scores between the groups (p > 0.05). Additionally, proprioception and muscle strength values displayed similarity between the groups (p > 0.05). The length of the remnant tissue did not affect post-operative knee stability (p > 0.05).

Patients who underwent remnant-preserving ACL reconstruction obtained similar proprioceptive function, muscle strength, anterior stability, and clinical results regardless of the amount of preserved tissue length at short-term assessment.

Information derived from functional return-to-sport (RTS) tests after primary anterior cruciate ligament (ACL) reconstruction (ACLR) can have a significant impact on the risk reduction of ACL reruptures. However, due to space, time, and financial limitations, few clinicians utilize objective data to assess their patients' functional abilities after ACLR.

To identify validated and feasible RTS tests that could reliably estimate the risk of reinjury after ACLR in everyday clinical practice beyond the highly sophisticated laboratory setting.

Systematic review; Level of evidence, 4.

A focused review was performed by experts of the committees for Ligament Injuries and Prevention/Rehabilitation of the German Knee Society. RTS functional tests, their reinjury prognostic values (if known), their reliabilities, and their implementation capacities were extracted from the original studies on the described RTS test setup, as well as from studies on potential test alternatives. These alternatives were required to be less resource-consuming yet still validated and thus able to be implemented into everyday practice. All tests were categorized according to their relevant target objective: isokinetic or isometric strength, functional (hopping and jumping) ability, or self-reported readiness.

In the final analysis, 19 studies involving 7513 patients were included. From these, a total of 21 RTS tests were retrieved, and 13 tests were included. For strength testing, 2 dynamic tests and 1 static test were found to be eligible. Functional ability was represented by 8 different jump, hop, and agility tests. Tests for self-reported readiness included the ACL-Return to Sport after Injury scale and the Knee injury and Osteoarthritis Outcome Score Sport and Recreation subscore. Alternative tests included the 8-repetition maximum test, handheld/portable dynamometer, single-leg vertical (countermovement) hop with inertial sensor or smartphone app, and the drop jump with knee displacement or normalized knee distance measurement.

For most of the strength and functional abilities assessed by RTS tests, validated and less resource-consuming alternatives do exist. Therapists and clinicians working in nonlaboratory settings may find it helpful to select from a menu of established RTS tests and test alternatives for each relevant target objective, depending on their individual requirements.

To compare rates of revisions between patients with isolated anterior cruciate ligament (ACL) reconstruction and those who had concomitant medial collateral ligament (MCL) injuries managed either operatively or nonoperatively at the time of index anterior cruciate ligament reconstruction (ACLR).

Using laterality-specific International Classification of Diseases, Tenth Revision (ICD-10) and Current Procedural Terminology (CPT) codes, we queried the PearlDiver-Mariner Database for all patients who underwent ACLR between 2016 and 2020. Patients were included if they were ages 15 or older and had a minimum of 2 years of follow-up after index ACLR. Patients were then divided into cohorts by presence or absence of concomitant MCL injury. The cohort of concomitant MCL injuries was further subdivided into those with MCL injuries managed nonoperatively, with MCL repair, or with MCL reconstruction at the time of index ACLR. Multivariate regression was performed between cohorts to evaluate for factors associated with revision ACLR.

We identified 47,306 patients with isolated ACL injuries and 10,846 with concomitant MCL and ACL injuries. In total, 93% of patients with concomitant MCL injuries had their MCL treated nonoperatively; however, the annual proportion of patients being surgically managed for their MCL injury increased by 70% from 2016 to 2020. Concomitant MCL injury patients had greater odds of undergoing revision ACLR compared with patients with isolated ACL injuries (odds ratio 1.50, 95% confidence interval 1.36-1.66, P < .001). Among patients with concomitant MCL injuries, surgically managed patients had a greater risk of revision ACLR compared with nonoperatively managed MCL injuries (odds ratio 1.39, 95% confidence interval 1.01-1.86, P = .034).

Despite an increase in operatively managed concomitant MCL injuries, most concomitant MCL injuries were still managed nonoperatively at the time of ACLR. Patients with concomitant MCL injuries, particularly those managed operatively, at the time of ACLR are at increased risk of requiring revision ACLR compared with those with isolated ACL injuries.

Level III, retrospective comparative case series.

Comprehensively explore current practices in preoperative rehabilitation (prehabilitation) for anterior cruciate ligament reconstruction (ACLR) and assess corresponding clinical outcomes and complication rates.

A systematic search of EMBASE, MEDLINE, Cochrane and PubMed was conducted from inception to 1 November 2024. All studies reporting outcomes and/or complications following prehabilitation and ACLR were included. Screening and data abstraction were designed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Revised Assessment of Multiple Systematic Reviews guidelines.

Thirty-six studies with 2326 patients undergoing prehabilitation and ACLR were included. Weighted averages of all clinical outcomes met or surpassed patient acceptable symptom state (PASS) thresholds and return to sports (RTS) criteria. There were no preoperative complications following prehabilitation. Major post-operative complications included graft failure (4.6%), contralateral ACL rupture (1.0%), surgical site infection (0.6%), deep infection (0.4%), non-ACL ligament injury (0.5%), reoperation for hardware removal (0.3%), muscle rupture (0.1%), patellar subluxation (0.1%) and patellar rupture (0.1%).

Current prehabilitation practices for ACLR emphasize impairment resolution, ROM restoration, and neuromuscular exercises. Safety of current practices is supported by the absence of preoperative complications and similar post-operative complication rates compared to patients undergoing standard care. Clinical outcomes of patients undergoing prehabilitation were shown to meet and surpass PASS thresholds and RTS criteria, expedite post-operative recovery, and maintain functional improvements up to 10 years post-operation, suggesting that prehabilitation is a safe and effective intervention yielding short- to long-term benefits. There is a need for further high-quality randomized controlled trials and large prospective cohort studies comparing the effect of prehabilitation on post-operative outcomes, reporting specific exercise details and protocol progression.

Level II.

Anterior cruciate ligament (ACL) injuries remain one of the most common and debilitating injuries that physically active individuals experience. Pain-related fear of movement and/or reinjury, or kinesiophobia, is the most frequently cited reason for not returning to sport after ACL reconstruction. Understanding how kinesiophobia may impact recovery of physical performance is essential to guide targeted rehabilitation.

Does kinesiophobia associate with physical performance in patients with a history of ACL reconstruction?

Five cross-sectional studies investigating bivariate relationships between kinesiophobia and metrics of physical performance among individuals with a history of primary, unilateral ACL reconstruction were included. From a strength perspective, greater kinesiophobia associated with lesser isometric knee flexion torque (n = 1, negligible association) but did not associate with isokinetic or isometric knee extension torque (n = 2). In terms of functional movement, greater kinesiophobia associated with asymmetric single-leg step-down performance (n = 1, high association) and shorter single-leg hop distance (n = 1, negligible association). Biomechanically, greater kinesiophobia associated with worse drop jump landing, characterized by greater frontal plane motion and lesser sagittal plane motion at the hip and knee joints (n = 1, low to high association).

Very low-quality evidence suggests a muscle-specific association between kinesiophobia and strength. Low- to moderate-quality evidence suggests that greater kinesiophobia associates with worse functional movement and landing biomechanics.

Considering the consistency and level of evidence among the included studies, we offer the following grades for each construct of physical performance evaluated: strength, D; functional movement, B; and biomechanics, B.

To evaluate differences in sport-specific concomitant injuries, return-to-sport (RTS), second ACL injuries and Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales after adolescent ACL reconstruction (ACLR) across popular sports.

This prospective cohort study included patients aged 10-18 years at ACLR. Demographic and injury-related data and KOOS subscales before ACLR and at the 1 and 2 years follow-ups were obtained. A survey to assess sport-specific outcomes and RTS was sent to eligible patients. Group comparisons were performed between the most popular sports and between females and males.

Overall, 1392 patients with a mean age of 16.4±1.4 years at ACLR were included. The mean time between ACLR and survey completion was 9.7±4.2 years. The most prevalent type of sport was soccer, followed by handball, floor hockey/field hockey, basketball and other sports. Concomitant injuries (71%) and second ACL injuries (30%; 20% ipsilateral, 13% contralateral) were common across all sports. No significant differences were found in ipsilateral second ACL injuries across sexes and sports. 24% of patients competed at an elite level sport (highest national level of junior sport or higher) for some period after ACLR. 8% of patients did not RTS at all, with females significantly more often without RTS than males (9% vs 4%, p=0.041). Significant improvements were observed in KOOS subscales from baseline to the 1 and 2 years follow-ups for all sports.

Concomitant injuries are frequently observed after ACL injury in adolescents, with nearly one-third suffering a second ACL injury. While significant improvements in KOOS subscales and return to high-level sports can be expected, better injury prevention is needed after ACLR.

Effective management of anterior cruciate ligament (ACL) injuries requires a comprehensive approach, from initial assessment, through treatment, rehabilitation, and discharge, however no gold standard care pathway exists to help guide clinicians. This case series provides an overview of current ACL injury management processes in six National Health Service (NHS) Trusts.

This study utilised a retrospective case series design within six NHS Trusts in the Yorkshire region of the United Kingdom. Using a standard operating procedure, each Trust selected ten consecutive ACL injured patients (≥ 16 years), managed either surgically or non-surgically. Data relating to the patient injury journey, patient and injury characteristics, key pathway events, rehabilitation management, outcome measures, and discharge, were collected. Data was anonymised and analysed using descriptive statistics.

Reviews covered 55 patients, median age 25.5 years, (41 males, 14 females). Median time to specialist assessment from injury was 12 days (Interquartile Range [IQR] 6 to 20 days), with 43 patients managed operatively, and 12 non operatively. The median number of physiotherapy sessions was 21 (IQR 9 to 29.5), with outcome measures being variably used across Trusts. Trusts using patient reported outcome measures (PROMS) consistently with their patients provided more physiotherapy appointments (34.5 and 27) and achieved higher return to sport (RTS) rates. Time from injury to discharge varied with a median of 421 (IQR 249 to 546) days. Discharge criteria were applied inconsistently across Trusts, with 31% of cases not using specific criteria. However, Trusts using standardised discharge criteria showed better RTS outcomes, with 27 (61%) patients successfully returning to sport.

This case series review highlighted some good practice in initial ACL management across six NHS Trusts in the Yorkshire region. However, from time to MRI diagnosis to discharge, substantial variation in care is observed. Whether treated operatively or non-operatively, for patients aiming to RTS, this was achieved with greater consistency when more physiotherapy appointments were undertaken, outcome measures and PROMs were used, and specific discharge criteria was utilised. Future larger pathway investigation studies incorporating causative and predictive analysis studies on a national scale are required to determine whether similar trends are observed in a wider ACL injured population, which could help to improve national pathways for patients and clinicians working towards ensuring more positive and standardised patient-related ACL injury outcomes.

A variety of criteria are used to make return to sport decisions after anterior cruciate ligament (ACL) reconstruction.

This systematic review summarized and evaluated prognostic factors and clinical prognostic models for returning to sports after ACL reconstruction.

Independent pairs of reviewers assessed eligibility, extracted data, and evaluated risk of bias and certainty of evidence. A systematic literature search was conducted in key electronic databases.

studies published in English, longitudinal cohort or case-control design, reporting outcomes on return to sport or Tegner Activity Score (TAS), participants aged ≥16 years undergoing primary ACL reconstruction, and defined as athletes/sport players or having a pre-injury TAS ≥5. Only associations between predictors and outcomes that were analyzed in ≥3 studies and had consistent results in the same direction in ≥75 % of the studies were considered and reported. Risk of bias was evaluated using the QUIPS or PROBAST tools, and certainty of evidence was evaluated using the GRADE framework.

37 studies (5 low, 6 moderate, and 26 high risk of bias) on prognostic factors and 1 study on prognostic models (low risk of bias), representing 6278 participants, were included. Six prognostic factors were identified and rated as very low certainty evidence: fewer concomitant meniscal injuries, shorter time between injury and surgery, higher jump test scores, better physical functioning, higher muscle strength, and greater psychological readiness to return to sport. Two prognostic models with AUC 0.77-0.78 and 70 % accuracy for predicting return to sport were identified.

There is a very low certainty of evidence that returning to sport is associated with both physical, psychological and demographic prognostic factors. More methodologically sound research on prognostic factors and prognostic models for return to sport in athletes after ACL reconstruction is needed.

Return to sport testing after ACL reconstruction (ACLR) is becoming increasingly popular. Anecdotally, some believe that patients who undergo a second ACL surgery on either the ipsilateral or contralateral leg progress through their rehabilitation goals faster the second time through. The purpose of this study was to evaluate the rate of strength progression in return to sport testing after primary and secondary ACLR surgeries in a young, active population.

A retrospective review of patients who underwent ACLR between September 2013 and December 2022 was performed. Patients were included if they underwent an ACLR and completed at least 2 postoperative strength tests. Strength testing was commonly performed at 3, 6, and 9 months. Exclusion criteria included age older than 30 and those who had a contralateral graft harvest. Structural equation modeling was performed for each strength assessment by the timepoint it was performed. A linear combination of parameters was performed to compare the path coefficients between the primary and secondary ACL groups for each strength test to assess statistical differences in the rate of change of each strength test over time.

Three hundred ninety-six patients in the primary ACLR group and 50 patients in the secondary ACLR group met the inclusion criteria. Patients who received secondary ACL surgery were older, had a higher percentage of BTB grafts, lateral augments, and internal brace augments. Months from surgery had a significant positive correlation with nearly all strength tests in both groups. There was no difference between primary and secondary surgery in the progression of any postoperative strength test. There was no difference in progression of IKDC or RSI scores between groups.

This study suggests that patients who undergo a second ACL surgery do not progress their strength faster or slower than after primary ACLR. This implies that these patients do not require different return-to-play protocols from a strength perspective.

Retrospective study, level III evidence.

InternalBrace™ technique (Arthrex, Naples, USA) has been applied in anterior cruciate ligament repairs in recent years as an alternative to the anterior cruciate ligament reconstruction, with several advantages. The present study aimed to investigate the optimal location to place the InternalBrace during surgery to reduce the stress on the repaired anterior cruciate ligament.

In silico study of a finite element model of the knee and the anterior cruciate ligament was developed to test the position of the InternalBrace at the repaired anterior cruciate ligament. Five different InternalBrace positions inside the anterior cruciate ligament were analysed under two conditions: with and without damage. Stress and strain in both the InternalBrace and the anterior cruciate ligament were evaluated and compared with a healthy condition (without InternalBrace). The computational simulations using the finite element method were performed under predefined boundary conditions observed during anterior cruciate ligament tears.

The peak strain (8.1%) was obtained in the damaged anterior cruciate ligament compared with a 4.8% strain in the undamaged anterior cruciate ligament in the case without InternalBrace with the same boundary conditions applied. The use of InternalBrace showed a decrease in the deformations of the anterior cruciate ligament, mainly when the InternalBrace was applied in the anteromedial bundle or crossed from the anterior cruciate ligament anteromedial tibial footprint to posterolateral femoral footprint.

The InternalBrace placement through the anteromedial bundle or crossed from the anteromedial tibial footprint to posterolateral femoral footprint showed the lowest peak stress and peak strain in the anterior cruciate ligament, with forces and deformation in the anterior cruciate ligament being partially shifted to the InternalBrace.

Level V.

Chaotic sporting environments require the performance of concurrent cognitive and motor tasks. A reduced capacity for either or both of the tasks when performed concurrently is known as cognitive-motor interference (CMi) and is believed to increase the injury risk. A greater susceptibility to CMi after a rupture of the anterior cruciate ligament (ACL) has been suggested to be caused by central nervous system adaptations, thus possibly contributing to high secondary ACL injury rates.

To investigate whether patients after ACL reconstruction (ACLR) demonstrate greater CMi than noninjured controls when adding secondary cognitive tasks to the drop vertical jump (DVJ) and explore the potential influence of sex on CMi.

Controlled laboratory study.

A total of 40 (50% male) sports-active patients who had undergone ACLR (mean, 24.9 ± 16.1 months after surgery) and 40 (50% male) sports-active noninjured controls performed DVJs with and without secondary cognitive tasks targeting short-term memory, attention, fast decision-making, and inhibitory control. Outcomes included a letter position recall task and 3 motor variables: (1) correct action (landing or landing with a subsequent vertical jump), (2) relative jump height (relative between DVJs), and (3) relative peak vertical ground-reaction force (relative between DVJs). Participants also completed isolated cognitive tests (CANTAB) included as covariates in multivariate analysis.

Multivariate analysis of variance revealed that the ACLR group had greater CMi than the control group (P < .001), as manifested by more incorrect answers for the cognitive letter recall task (mean difference [MD], -13.3% [95% CI, -20.8% to -5.9%]; P < .001), more incorrect motor actions (MD, -7.5% [95% CI, -12.4% to -2.6%]; P = .003), and a reduced relative jump height (MD, -4.5% [95% CI, -7.9% to -1.2%]; P = .010). No difference in relative peak vertical ground-reaction force was found (MD, 2.8% [95% CI, -7.7% to 13.3%]; P = .59). Isolated cognitive outcomes did not affect these results, and there were no significant differences between male and female participants.

Patients after ACLR showed greater CMi than noninjured controls, which was unrelated to isolated cognitive outcomes, thus indicating aberrant neurocognitive function.

Clinicians should consider cognitive and dual-task training and screening during ACL rehabilitation to better prepare patients for chaotic and uncontrolled sporting environments in which dual tasking is prevalent. Such interventions may help to reduce the risk of secondary ACL injuries.

Rupture of the anterior cruciate ligament (ACL) is a common sports injury. Despite continuous improvements over the years, not all patients return to their preoperative activities after treatment of the ACL. Therefore, individualized treatment approaches based on transplant selection, reconstruction technique and biomechanical factors, such as the tibial slope and rotational instability are crucial. Autogenous transplants have different properties in terms of donor site morbidity, healing behavior and risk of rerupture. The individual needs of the patient should therefore be taken into consideration. In terms of the surgical technique, correct tunnel placement based on anatomical landmarks is essential. In addition, concomitant instabilities and meniscus injuries must be addressed. In the event of a rerupture, an exact analysis of the causes is necessary. Ultimately, the success of the treatment depends to a large extent on precise diagnostics and the treatment of both the ACL rupture and any injured accompanying structures.

Anterior cruciate ligament (ACL) rupture is one of the most common knee injuries. Despite the effectiveness of reconstruction, re-rupture rates of up to 15 ​% have been reported. Static and dynamic test of strength and movement control have been used to determine when return to sports (RTS) is appropriate.

To determine whether successfully passing return to sport (RTS) tests reduces the re-rupture rate.

Retrospective cohort study. Patients who underwent ACL reconstruction (ACLR) from June 2018 to May 2023, and who performed RTS tests after rehabilitation, were analyzed. Patients who, in addition to ACLR, underwent extra-articular tenodesis, osteotomy, or multiligament injuries were excluded. RTS tests included the following: repeat sprint ability, dynamic valgus, proagility, unilateral counter movement jump (CMJ), isokinetic, triple hop test, and functional movement screen (FMS). All statistical analyses were performed with STATA version 18.0.

Ninety five patients underwent RTS tests after ACLR, with a follow-up time of 27.8 months. 71.6 ​% of patients were men with a mean age of 25.15 ​± ​10.7 years. The overall re-rupture rate was 13.68 ​% (13 patients). When comparing patients who passed and did not pass the RTS tests, there were no differences by sex (p ​= ​0.06) or age (p ​= ​0.11). The only statistically significant difference between the groups was the mean risk score (passed: 11.5 ​± ​0.7 vs. not passed: 15.5 ​± ​2.1; p ​< ​0.001). Patients with re-rupture were more likely to be from the non-passed group (passed: 0 ​% v/s not passed: 18.1 ​%; p ​= ​0.03), with a statistical power of 0.70.

Our records show that passing RTS test after an ACLR could guarantee the absence of re-rupture in the medium term.

Level IV.

Anterior cruciate ligament (ACL) injuries can pose significant challenges for athletes, leading to significant morbidity, loss of playing time, and impaired performance. Neuromuscular training programs, such as the FIFA 11+, have shown promise in reducing the risk of lower extremity injuries in this high-risk population.

The purpose of this study was to evaluate the effect of the FIFA 11+ program on lower extremity biomechanics during a drop vertical jump (DVJ) and to determine whether it modifies the athlete's risk of an ACL injury. It was hypothesized that the FIFA 11+ program would positively affect lower limb biomechanics during a DVJ in varsity athletes by decreasing initial coronal (IC) and peak coronal (PC) knee abduction angles while increasing peak sagittal (PS) knee flexion angles.

Cohort study; Level of evidence, 2.

A total of 36 collegiate varsity athletes (72 knees) were recruited for this investigation. The intervention group included female and male soccer players who incorporated the FIFA 11+ program into their pregame warm-up. The control group consisted of female hockey players who participated in a "standard" warm-up. The FIFA 11+ program was conducted twice weekly over 10 weeks. Biomechanical data before and after the intervention during DVJs, captured using a motion sensor, were compared between the intervention and control groups.

The intervention group showed a significant reduction in PC angles from high risk to low risk and a significant decrease in PS angles, while IC angles remained unchanged. Conversely, the control group showed a significant increase in IC angles from low risk to high risk, with no notable changes in PC and PS angles.

This study demonstrated that the FIFA 11+ program effectively reduced PC knee abduction angles, with a decrease in this parameter indicating an overall shift from high- to low-risk biomechanics in the intervention group. Additionally, worsening postseason knee biomechanics in the control group highlighted that the injury risk increased throughout the season when a targeted neuromuscular training program was not incorporated into pregame warm-ups. This suggests that the FIFA 11+ program mitigates key biomechanical risk factors for noncontact ACL injuries.

Quadriceps tendon (QT) autograft has emerged as an increasingly popular graft for anterior cruciate ligament reconstruction (ACLR). The modified Star Excursion Balance Test (MSEBT) measures dynamic balance and is frequently used in evaluating preparedness to return to sport as part of return-to-sport test batteries. There is limited information available about the MSEBT performance of patients who have undergone ACLR with QT autograft.

The purpose was to compare the MSEBT performance at 12 months after primary ACLR of patients with QT autografts with the performance of patients with hamstring tendon (HS) autografts. It was hypothesized that there would be a difference in the 2 groups due to harvest from either an extensor or a flexor of the knee joint.

Cohort study; Level of evidence, 3.

The cohort consisted of 132 patients (44 patients with QT, 88 patients with HS) who had undergone primary ACLR with either a QT or HS autograft, were <30 years of age at the time of surgery, and had participated in sports regularly before injury. Patients with contralateral anterior cruciate ligament injury or an additional lateral extra-articular tenodesis were excluded. The mean age of the patients was 22.1 years, and 18% were female. The anterior reach, posterolateral reach, and posteromedial reach on the MSEBT were recorded at 12 months postoperatively and normalized to leg length. The limb symmetry index (LSI) and the composite score (CS) were calculated for each measurement. Patient-reported outcome measures were also collected.

There were no significant differences between the mean LSI and the CS of the QT and HS groups for any reach direction of the MSEBT (LSI: QT = 99.9 and HS = 98.9 for anterior reach, QT = 100.9 and HS = 100.2 for posterolateral reach; QT = 101.1 and HS = 100.8 for posteromedial reach, CS: QT = 96.6 and HS = 96.9). Patient-reported outcome measures also showed no significant difference.

There were no differences in symmetry between QT and HS grafts in MSEBT performance at 12 months, with both patient groups having >98% limb symmetry in each reach direction.

Reactive and external visual-cognitive demands are prevalent in sport and likely contribute to anterior cruciate ligament (ACL) injury scenarios. However, these demands are absent in common return-to-sport assessments. This disconnect leaves a blind spot for determining when an athlete can return to sport with mitigated re-injury risk.

To characterize relationships between patient-reported outcome measures (PROMs) and cognitive-task interference (i.e., cognitive demands exacerbating neuromuscular impairments) for biomechanical predictors of second ACL injuries during jump landings that involved rapid unanticipated decision making.

Thirty-six persons following primary ACL reconstruction (ACLR; 26 females/10 males, 19.8 ± 1.8 yr; 1.71 ± 0.1 m; 69.6 ± 12.8 kg, 1.5 ± 0.6 yr post-ACLR; Tegner: 6.8 ± 1.8) participated. PROMs of ACL-RSI and the Forgotten Joint Score-12 Knee (FJS-12) were selected to assess altered psychological state (e.g., confidence, attention toward knee). Jumping tasks under anticipated and unanticipated secondary jump directions were performed. Biomechanical variables were dual-task changes (unanticipated - anticipated) in 1) uninvolved limb hip rotator impulse (DTC_Uni-HRot_Imp), 2) asymmetry of knee extensor moment at initial contact (DTC_KEM_Asym), and 3) range of involved knee abduction angle (DTC_KAbA_Range). Regression models tested for relationships between PROMs and the dual-task change in biomechanical variables.

ACL-RSI (DTC_Uni-HRot_Imp ( P < 0.001)) and FJS-12 (DTC_KAbA_Range ( P = 0.001)) had significant relationships with dual-task change in the opposite direction as expected (worse PROM ➔ less dual-task change). A follow-up analysis indicated that dual-task change was inversely correlated with the baseline estimates for kinetic biomechanical variables (less risky single-task biomechanics ➔ greater dual-task change for Uni-HRot_Imp and KEM_Asym).

The collective results are consistent with higher functioning participants (better PROMs) who also demonstrate desirable biomechanics during single-task conditions being prone to demonstrating the greatest risk-associated DTC in unanticipated scenarios.

The capacity of functional testing to identify 'at-risk' landing strategies in return to sport evaluation has been questioned. The purpose was to evaluate if biomechanical and muscle activation patterns differ during a drop landing task in subjects post anterior cruciate ligament reconstruction against uninjured controls.

22 subjects within two years of anterior cruciate ligament reconstruction who had returned to sport and 25 activity matched controls were recruited. Sagittal plane knee and hip biomechanics and muscle activation amplitudes were recorded during a single leg drop landing task. Discrete measures derived from waveforms were analysed using t-tests and Analysis of Variance models (α=0.05).

Subjects post anterior cruciate ligament reconstruction displayed reduced knee (Effect Size = 1.2) and hip (Effect Size = 0.995) range of motion as well as reduced knee extension moments (Effect Size = 0.955) but exhibited no differences in quadriceps or hamstrings activation amplitudes versus uninjured controls.

Adoption of reduced knee and hip excursion or "stiffened" landing pattern despite similarities in muscle activation suggests the presence of adaptive strategies reflecting incomplete recovery despite receiving clearance for returned to sport. This suggests presence of altered patterns of movement which may place at increased risk for reinjury.

An anterior cruciate ligament (ACL) injury is a severe condition that may affect the career of young athletes. There is limited evidence on the rate and level of return to sport (RTS) after pediatric and adolescent ACL reconstruction.

To evaluate clinical outcomes, the level and rate of RTS, and predictive factors for RTS after pediatric and adolescent ACL reconstruction.

Cohort study; Level of evidence, 3.

Patients aged between 10 and 18 years at the time of primary ACL reconstruction were screened for eligibility. Based on age at the time of ACL reconstruction, patients were divided into the pediatric (female: 11-13 years; male: 11-15 years) and adolescent (female: 14-18 years; male: 16-18 years) groups. Patient-specific, injury-related, and treatment-specific data, as well as subscores of the Knee injury and Osteoarthritis Outcome Score (KOOS) at baseline and 1-, 2-, 5-, and 10-year follow-up, were obtained. A survey consisting of 3 patient-specific and 30 knee-related questions was developed by experts in the management of ACL injuries and was sent to all patients to determine sport-specific variables and RTS rates.

Overall, 1392 patients (total response rate: 24%) were included in this study. There were 81 pediatric patients (mean age at ACL reconstruction, 13.7 ± 1.4 years) and 1311 adolescent patients (mean age at ACL reconstruction, 16.5 ± 1.2 years). Significant improvements in KOOS subscores were observed after both pediatric and adolescent ACL reconstruction at each follow-up time point. After ACL reconstruction, 74% of pediatric patients and 68% of adolescent patients returned to their previous type of sport (P = .23). Moreover, 31% of pediatric patients and 23% of adolescent patients became elite athletes (highest national level of junior sport or higher) after ACL reconstruction (P = .13). A cartilage injury at the time of ACL reconstruction was found to lower the odds of pediatric and adolescent patients returning to their previous type of sport (odds ratio, 0.60; P = .001). A second ACL injury occurred in 25% and 31% of pediatric and adolescent patients, respectively (P = .29).

Long-lasting clinical improvements and high RTS rates can be expected after pediatric and adolescent ACL reconstruction. Moreover, young athletes still have the chance to compete at an elite level of sport after ACL reconstruction.

Revision surgery after anterior cruciate ligament reconstruction (ACL-R) is hypothesized to be the result of an interplay between factors associated with the anatomy, physiological characteristics and environment of the patient. The multifactorial nature of revision ACL-R risk is difficult to quantify, and evidence regarding the independent roles of potentially important variables is inconsistent throughout the literature. Young patient age is often cited as one of the most prominent risk factors for reinjury after ACL-R. However, the association between a non-modifiable variable such as patient age and revision ACL-R risk is likely to be a spurious correlation due to the confounding effect of more important variables. From the perspective of healthcare professionals aiming to mitigate revision ACL-R risk through targeted interventions, awareness of factors like generalized joint hypermobility, bone morphology, muscle strength imbalances, and genetic factors is critical for the individualized risk assessment of patients with ACL injury. The aim of this current concepts article is to raise awareness of the essential anatomical, physiological, and activity-related risk factors associated with ACL injury and reinjury risk that are likely captured and confounded by patient age. LEVEL OF EVIDENCE: Level V.

To evaluate the association between limb symmetry index (LSI) in quadriceps and hamstrings strength together with hop tests, as a proxy of recovery, and the deviation from being symmetrical (LSI 100%), with a safe return to sport (RTS) after anterior cruciate ligament reconstruction (ACL-R).

Athletes between 15 and 30 years old with a preinjury Tegner activity level ≥6 were eligible for inclusion. Data were extracted from a rehabilitation-specific registry, Project ACL (Gothenburg, Sweden) at the time of or after RTS for each athlete. The outcome of interest in this study was a safe RTS-not suffering a second ACL injury within 2 years from RTS-addressed by using the LSI in five different ways with results from the test battery which include five tests of muscle function at or after the time of RTS. Logistic regression analyses were performed with safe RTS as a dependent variable and presented with ORs and 95% CIs.

In total, 233 athletes (51.1% women) were included. The best-differentiating cut-offs for strength and hop tests showed non-significantly poor discriminatory ability between athletes who had a safe RTS and those who did not (Youden J 0.09-0.24 and area under the curve 0.50-0.59). Athletes who had ≥80% or ≥85% LSI had significantly lower odds of safe RTS compared with athletes who did not meet the cut-offs of safe RTS (OR=0.32 (95% CI 0.12 to 0.87) and OR=0.39 (95% CI 0.18 to 0.84), respectively). There was no effect of a 1% increase in LSI or deviation from 100% symmetry on safe RTS.

The use of LSI from tests of muscle function to determine safe RTS after ACL-R, that is, RTS without sustaining a second ACL injury within 2 years, cannot differentiate between athletes who had a safe RTS and those who did not, regardless of whether LSI was used as cut-offs, incremental or as deviation from symmetry. Thus, it is of clinical importance that clinicians do not solely rely on the LSI to clear athletes for RTS.

Failure, persistent knee instability, and reinjury rates after anterior cruciate ligament (ACL) reconstruction are still concerns. Biomechanical investigations have highlighted the role of the anterolateral ligament (ALL) as a crucial knee stabilizer, and clinical outcomes after combined ACL and ALL reconstruction appear to indicate the success of the procedure.

To compare the functional outcomes, return-to-sport (RTS) rate, and complications between combined ACL and ALL reconstruction and isolated ACL reconstruction.

Meta-analysis; Level of evidence, 4.

The PubMed/MEDLINE, Scopus, and Cochrane Central databases were used to search keywords, and a total of 16 studies were included. The data extracted for quantitative analysis included the Tegner activity scale score, Lysholm knee score, International Knee Documentation Committee (IKDC) score, laxity measured using the KT-1000 knee arthrometer, number and types of complications, RTS rate, and survival rate. Random- and fixed-effects models were used for the meta-analysis of pooled mean differences and odds ratios.

A total of 2329 patients were identified, 1116 of whom underwent combined ACL and ALL reconstruction and 1213 of whom underwent isolated ACL reconstruction. The mean ages were 25.4 ± 7.2 years and 26.5 ± 7.8 years for the combined ACL and ALL reconstruction and isolated ACL reconstruction groups, respectively. The mean follow-ups were 40.3 ± 21.4 months and 42.5 ± 21.6 months, respectively. Comparable Tegner activity scale (P = .16), Lysholm knee (P = .13), and IKDC (P = .83) scores were found between groups. Significantly greater postoperative knee laxity was found in the isolated ACL reconstruction group (mean difference, -0.44; 95% CI, -0.85 to -0.04; P = .03). The combined ACL and ALL reconstruction group showed a significantly lower rate of graft failure (odds ratio [OR], 0.37; 95% CI, 0.18-0.77; P = .008), a higher RTS rate (OR, 1.41; 95% CI, 1.11-1.80; P = .005), and a higher survival rate (OR, 2.94; 95% CI, 1.97-4.37; P < .001).