Fifty-five per cent return to competitive sport following anterior cruciate ligament reconstruction surgery: an updated systematic review and meta-analysis including aspects of physical functioning and contextual factors

Editorial Commentary: Proper graft choice and lateral extra-articular tenodesis are key to successful anterior cruciate ligament reconstruction in female soccer players

Over the last decade, techniques and outcomes of anterior cruciate ligament reconstruction (ACLR) have evolved dramatically. We have improved our graft choices from favoring autograft over allograft in younger patients and transitioned from transtibial to independent drilling to improve our femoral tunnel position, but our outcomes were still disappointing in high risk populations such as those with generalized ligament laxity and female soccer (football) players with low return to sports rates, incomplete restoration of rotatory stability, and relatively high rates of osteoarthritis. With the renewed focus on extra-articular procedures, predominantly anterolateral ligament (ALL) reconstruction and lateral extra-articular tenodesis (LET), and avoiding the use of isolated soft-tissue grafts for high-risk patients, outcomes have significantly improved over the last decade. The indications for extra-articular procedures have expanded and the minimal downsides seem to validate this trend. Careful documentation and monitoring of long-term incidence of post-traumatic osteoarthritis will be the final step in implementing these additional procedures most active patients.

Is the knee joint more vulnerable to injury in unplanned cutting tasks? An EMG vector field analysis of high-level female athletes

OBJECTIVES

Neuromuscular activation and peak external knee abduction moments (pKAM) are risk factors for anterior cruciate ligament injuries during sidestep cutting. This study aimed to: 1) compare thigh muscle activity between preplanned and unplanned sidestep cuts, 2) assess rank correlations of mean thigh muscle pre-activity in both cuts, 3) investigate the relationship between pKAM and thigh muscle activity in 31 experienced female handball players.

METHODS

Four-component (vastus medialis, vastus lateralis, semitendinosus, biceps femoris) electromyogram vector fields were compared from 100 ms before ground contact until toe-off using Statistical Parametric Mapping. Spearman's rank correlation coefficient was used to assess rank correlations of mean pre-activity of individual muscles between cuts. Relationships between pKAM and the four-component electromyogram vector fields were assessed using Canonical Correlation Analysis.

RESULTS

Four-component muscle activity differed before ground contact and push-off, mostly due to activity differences in muscle pairs. Individual analyses showed lower vastus medialis activity in unplanned cuts right before ground contact. High pre-activity rank correlations were found for vastus medialis and lateralis, moderate for semitendinosus, and none for biceps femoris between preplanned and unplanned cuts. Canonical correlation analyses indicated no relationship between muscle activity and pKAM.

CONCLUSION

The knee might be more vulnerable to injury in unplanned tasks due to lower muscular pre-activity. Muscle activity does not vary with pKAM, suggesting passive structures must absorb higher loads with increasing pKAM. Differences in vastus medialis pre-activity and inconsistencies in biceps femoris pre-activity ranking highlight areas for targeted neuromuscular training to better protect the knee against external loads.

Synthetic augmentation in ACL reconstruction may reduce re-rupture rates and increase return-to-sport rates: A systematic review and meta-analysis

PURPOSE

Synthetic augmentation (SA) in anterior cruciate ligament reconstruction (ACLR) aims to enhance graft durability, but its benefits remain unclear. To evaluate whether SA in ACLR improves return-to-sport (RTS) rates, reduces graft failure, enhances patient-reported outcomes (PROs) and varies in effectiveness across materials and techniques.

METHODS

A systematic search of five databases was conducted until February 2025. Comparative studies were pooled using Hedges' random-effects meta-analysis with subgroup analysis based on materials and publication year. Non-comparative studies were analysed narratively. Risk of bias was assessed using the Risk of Bias in Non-randomised Studies of Interventions and the Cochrane risk-of-bias tools for randomised studies. Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach was used to assess the certainty of evidence.

RESULTS

Forty-seven studies were included (n = 4289): 7 randomised and 40 non-randomised studies (21 comparative; 19 non-comparative). SA systems included InternalBrace (FiberTape, 16 studies), Ligament Augmentation and Reconstruction System (polyester, 5), Ligament Augmentation Device (polyethylene, 18) and other materials (8). GRADE assessment showed moderate-certainty evidence for improved mid-term RTS rate from eight studies (odds ratio [OR]: 1.58; 95% confidence interval (CI): 1.12-2.22; N = 716; I2 = 0%; p = 0.01). Internal brace showed a reduction in re-rupture rates in the long-term (OR: 0.17, 95% CI: 0.04-0.64; N = 218; I2 = 0%; p = 0.01); however, pooled analysis of all techniques showed no statistically significant difference. Contemporary studies showed a better return to sport rates with SA. PROs showed no clinically meaningful differences. Non-comparative studies showed low graft failure rates (<8.7% for InternalBrace; <16.4% for other SA), high RTS rates (>90% for InternalBrace; >56.7% for other SA) and satisfactory PROs.

CONCLUSIONS

SA, particularly InternalBrace, may improve RTS rates and reduce re-rupture risk, though PROs remain inconclusive. Findings are limited by a moderate-to-serious risk of bias, emphasising the need for high-quality research.

LEVEL OF EVIDENCE

Level III.

Influence of Neuromuscular Training Interventions on Jump-Landing Biomechanics and Implications for ACL Injuries in Youth Females: A Systematic Review and Meta-analysis

BACKGROUND

Various exercise interventions are recommended to reduce the risk of anterior cruciate ligament (ACL) injury in females. However, the extent to which these training interventions influence lower-limb landing biomechanics in youth female remains unclear.

OBJECTIVE

This systematic review and meta-analysis aimed to quantitatively summarise the effectiveness of various training interventions on jump-landing biomechanics in youth females.

METHODS

We systematically searched PubMed, SPORTDiscus, EMBASE and Scopus. Articles were included if they: (1) conducted research on uninjured youth females (reported mean age < 18 years) with no restriction on playing level/experience or physical activity level; (2) performed any form of training intervention for ≥ 4 weeks; (3) reported any lower-limb kinematic (flexion/extension, adduction/abduction or internal/external rotation angles) or kinetic (joint moments or vertical ground reaction forces) data during the landing phase of jump-landing tasks, pre- and post-training intervention for both experimental and control groups, using a two- or three-dimensional motion capture system; (4) were randomised- or non-randomised controlled trials. The quality of the randomised controlled trials was assessed using the Risk of Bias tool 2, whereas the Downs and Black checklist was used for assessing the quality of non-randomised controlled trials. A multi-level meta-analytical model was used for conducting the quantitative analysis.

RESULTS

Thirteen studies (7 randomised controlled, 6 non-randomised controlled studies) involving 648 female participants were included in the final analyses. With regards to the overall quality of the included studies, three studies had high risk of bias while ten studies had some concerns. As part of the meta-analysis, we were able to analyse seven kinematic variables and two kinetic variables in aggregate. Compared with controls, the experimental group had significantly increased peak knee flexion angle (g = 0.58, p = 0.05) and reduced knee valgus motion (g =  - 0.86, p = 0.05) post-intervention. The effects on other kinematic and kinetic variables ranged from trivial to moderate and were not significantly altered as a result of various training interventions.

CONCLUSION

The findings from the synthesised literature indicate that training interventions have small to moderate effects on peak knee flexion angle and knee valgus motion during jumping tasks. However, further research employing more consistent study designs and methodologies is required to better understand the changes in jump-landing biomechanics in the youth female population following training interventions.

Rethinking the Assessment of Arthrogenic Muscle Inhibition After ACL Reconstruction: Implications for Return-to-Sport Decision-Making-A Narrative Review

Arthrogenic muscle inhibition (AMI) is a neuromuscular impairment commonly observed following anterior cruciate ligament reconstruction (ACLR). This condition, characterized by persistent quadricep inhibition due to altered afferent feedback, significantly impacts neuromuscular recovery, delaying return to running and sport. Despite advancements in rehabilitation strategies, AMI may persist for months or even years after ACLR, leading to muscle strength asymmetries, altered biomechanics, and an increased risk of reinjury. The mechanisms underlying AMI involve both peripheral (joint effusion, mechanoreceptor dysfunction) and central (corticospinal inhibition, neuroplasticity alterations) components, which collectively hinder voluntary muscle activation and movement control. AMI alters gait mechanics, reduces knee stability, and promotes compensatory patterns that increase injury risk. Current return-to-sport protocols emphasize strength symmetry and functional performance but often neglect neuromuscular deficits. A comprehensive assessment integrating neuromuscular, biomechanical, and proprioceptive evaluations is needed at specific stages to optimize rehabilitation and minimize reinjury risk. Future research should explore targeted interventions such as neuromuscular stimulation, cognitive-motor training, and advanced gait analysis to mitigate AMI's impact and facilitate a safer, more effective return to sport.

Return to sport after anterior cruciate ligament reconstruction - prognostic factors and prognostic models: A systematic review

BACKGROUND

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

OBJECTIVES

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

METHODS

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.

INCLUSION CRITERIA

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.

RESULTS

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.

CONCLUSION

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.

Patients follow four clusters of participation in physical exercise after an ACL injury. Results from the NACOX cohort study

OBJECTIVES

To explore how participation in physical exercise (PE) changes over time after an anterior cruciate ligament (ACL) injury. Additionally, to identify factors associated with participation in PE by analyzing longitudinal data.

DESIGN

An explorative analysis of the NACOX study, a prospective multicenter cohort study.

METHODS

Patients with an acute ACL injury aged 15-40 years were followed for three years. The patients regularly reported participation in PE, knee function, new injuries, and surgeries. State sequence analysis and Hierarchical Cluster Analysis were used to analyze participation in PE. Clusters were compared using an analysis of variances, the Chi-square test, and Fischer's exact test.

RESULTS

The study included 275 patients, 52 % female, with a mean age of 25 years. Four clusters were identified, varying from low to high participation in PE after an ACL injury. Clusters differed regarding the number of ACL reconstructions (ACLR) (p = 0.03); time from injury to ACLR (p = 0.03); patient-reported knee function at the follow-ups at 3 months (p = 0.02), 6 months (p = 0.02), and 12 months (p = 0.02) after injury; PE level before injury (p < 0.001); and number of new injuries and surgeries (other than ACLR) (p = 0.001).

CONCLUSIONS

Four clusters, varying from low to high participation in PE after an ACL injury were identified. The results provide valuable insight into factors associated with different levels of participation in PE, which can be helpful for healthcare personnel working with ACL rehabilitation.

Efficacy of complex decongestive therapy in managing limb swelling, pain, and enhancing functional recovery after arthroscopic reconstruction of anterior cruciate ligament

OBJECTIVE

To evaluate the efficacy of Complex Decongestive Therapy (CDT) in managing limb swelling, alleviating pain, and promoting functional recovery in patients following anterior cruciate ligament reconstruction (ACLR).

METHOD

This was a randomized controlled trial (RCT) involving 160 patients who underwent ACLR at a tertiary hospital in Shenzhen between August 2021 and April 2023. The study compared the outcomes of conventional nursing care with complex decongestive therapy (CDT). The differences in leg circumference, Visual Analog Scale (VAS) pain scores, and Active Range of Motion (AROM) were assessed at six time points during the perioperative period and up to 30 days post-surgery.

RESULTS

This study included 69 patients in the experimental group and 64 patients in the control group. After one month of treatment with CDT, significant differences in calf circumference were observed between the experimental and control groups on the 3rd (t = -2.083, P = 0.039) and 5th (t = -2.078, P = 0.040) postoperative days. Regarding changes in central patellar circumference, a significant difference was noted on the 5th postoperative day (t = -2.092, P = 0.038) in the experimental group. However, no significant differences in thigh circumference were observed at any of the six time points (P > 0.05). Visual analog scale (VAS) pain scores were significantly different on the 1st (t = -1.978, P = 0.048) and 3rd (t = -2.530, P = 0.011) postoperative days. Lysholm scores showed a significant difference between the groups on the 30th postoperative day (t = -3.438, P = 0.001), with no significant difference observed before surgery (P > 0.05). Significant differences in AROM were found on the 14th (t = -3.919, P = 0.000) and 30th (t = -2.615, P = 0.009) postoperative days.

CONCLUSION

CDT can effectively reduce limb swelling on the 3rd and 5th postoperative days, alleviate pain on the 1st and 3rd postoperative days, and enhance joint functional recovery on the 14th and 30th postoperative days.

Drop landing between subjects post anterior cruciate ligament reconstruction and uninjured controls: A biomechanical and neuromuscular analysis

BACKGROUND

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.

METHODS

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).

FINDINGS

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.

INTERPRETATION

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.

The Arabic Version of Injury-Psychological Readiness to Return to Sport Scale: Translation and Psychometric Validation

Background and Objectives: It is crucial to consider not only the physical variables but also the athlete's psychological condition prior to making the decision to return to sport (RTS). It is unfortunate that there is currently no universal questionnaire available in Arabic to determine whether an athlete is ready to return to sports. So, this cross-cultural validation study was carried out to translate and validate the Injury-Psychological Readiness to Return to Sport Scale (I-PRRS) into the Arabic language. Materials and Methods: One hundred twenty athletes with lower extremity injuries (95 males and 25 females) completed the Arabic I-PRRS twice with a one-week time interval. An additional 50 athletes, comprising 40 males and 10 females, also participated in the study by completing the questionnaire during their initial visit to a physical therapist. Floor and ceiling effects, internal consistency, reliability, discriminate validity, convergent validity, and factor construct were analyzed. Results: The I-PRRS was translated into Arabic with no floor or ceiling effects. It had good internal consistency (0.84) and excellent test-retest reliability (ICC 0.88, 95% CI 0.73-0.95) where the lower bound of 95% CI indicated at least good reliability. The SEM was 1.14, and the MDC was 3.27 points. Athletes who were cleared to RTS demonstrated significant differences in their responses compared with those who were visiting their physical therapist for the first time. These differences were significant across all individual items, as well as in the total scores of the assessment (p < 0.001). There was a significant moderate correlation between overall scores on the I-PRRS and the Tampa Scale of Kinesiophobia (TSK) (rs = 0.69, p < 0.05). Conclusions: The Arabic version of the I-PRRS demonstrated good reliability and validity, making it a suitable tool for evaluating psychological readiness to RTS among injured athletes in Arabic-speaking populations.

Thai version of ACL return to sports after injury scale translated with cross-cultural adaptation provided the good validation in Thai patients who received ACL reconstruction

PURPOSE

The Anterior Cruciate Ligament Return to Sports after Injury scale (ACL-RSI) has been translated and culturally adapted into the Thai version. This study aimed to evaluate the reliability and validity of the Thai ACL-RSI for athletes recovering from ACL reconstruction.

METHODS

This study was a cross-sectional study. Forward-backward translation, cultural adaptation, and validation of the Thai ACL-RSI were performed and tested in 40 athletes (8 females, 32 males; mean age 30.2 ± 7.32 years; mean body weight 70.7 ± 13.36 kg; mean height 170.1 ± 6.53 cm; mean body mass index 24.5 ± 3.74 kg/m2; mean time from surgery to evaluation 8.43 ± 1.83 months). Participants completed the translated Thai ACL-RSI and the validated Thai Tampa Scale of Kinesiophobia (TSK). The Thai ACL-RSI underwent content validity, internal consistency, reliability, and construct validity assessment.

RESULTS

The Thai ACL-RSI demonstrated commendable content validity (item-objective congruence index [IOC] 0.91), internal consistency (Cronbach's alpha coefficient 0.84), and test-retest reliability (intraclass correlation coefficient [ICC] 0.75). There was a significant negative correlation with TSK (r = -0.67, p < 0.001).

CONCLUSION

The Thai ACL-RSI is validated, reliable, and consistent with the Thai TSK. This instrument can potentially measure psychological factors influencing preparedness for sports participation after ACL reconstruction. The evaluation of return-to-sport readiness should involve a multidisciplinary approach, including surgeons, physiotherapists, and psychologists, to ensure a comprehensive assessment of physical, functional, and psychological factors.

Rehabilitation volume, psychological readiness, and motor function are important factors for a successful return to sport after anterior cruciate ligament reconstruction: A 2-year follow-up cohort study

OBJECTIVES

To find contributors to return to sport success or time until return to sport in individuals after an anterior cruciate ligament reconstruction.

DESIGN

Cohort study.

METHODS

Secondary analysis of the data of two intervention studies.

PARTICIPANTS

We included adults < 36 years of age with a tendon autograft anterior cruciate ligament reconstruction who were active in any type of sport prior to the injury and aiming to return to sport. All participants were prospectively monitored for 24 months.

INTERVENTIONS

At the end of the individual post-surgery rehabilitation and re-injury prevention programmes, self-report- and objective functional outcomes were quantified.

MAIN OUTCOME MEASURES

The potential return to sport success (return to the same type of sports, frequency, intensity, and quality of performance as pre-injury), secondary injuries, and all rehabilitation and training measures were prospectively monitored. To determine the contributing factors, Cox regressions for traits and baseline factors and a logistic mixed model, which also included prospective time-dependent factors, were calculated.

RESULTS

203 participants were included; 104 (51 % of the total sample and 68 % of the full cases) successfully returned to their sporting activity. The median duration until return to sport was 302 days (interquartile range was 114 days). Contributing factors were the type of working (blue- vs. white collar: odds ratio for return to sport = 0.51 [95 % confidence interval = 0.29 to 0.90]) and the athletic status (elite vs. non-elite: odds ratio = 2.28 [1.03 to 5.03]). Prospectively, higher rehabilitation volumes until the end of the rehabilitation were predictive for return to sport success: the odds ratio per additional hour of rehabilitation was 1.004 [1.001 to 1.006]. Functional abilities such as the normalised knee separation distance during drop jump landing (odds ratio = 0.961 [0.924 to 0.999]) were predictive at a later stage, at the end of the re-injury prevention. Psychological readiness for return to sport was predictive at most of the timepoints: those who were confident to return to sport were more successful to return to sport at the end of the rehabilitation (odds ratio = 1.029 [1.004 to 1.056]) and at the end of the re-injury prevention (odds ratio = 1.038 [1.004 to 1.073]).

CONCLUSIONS

The most important factors for a successful pre-injury-level return to sport after anterior cruciate ligament reconstruction were the exercise volume, psychological readiness and functional hop/jump abilities. Whilst the impact of these modifiable factors was robust against multilevel modelling, the impact of athletic and working status vanishes when the prospective factors are included.

Primary Anterior Cruciate Ligament Reconstruction in Level 1 Athletes: Factors Associated With Return to Play, Reinjury, and Knee Function at 5 Years of Follow-up

BACKGROUND

Favorable outcomes after anterior cruciate ligament (ACL) reconstruction (ACLR) are often gauged by successful return to play (RTP), a low incidence of subsequent ACL injury, and positive patient-reported outcomes. Level 1 sports place the highest demands on the knee by requiring frequent pivoting, changes in direction, and jumping.

PURPOSE

To analyze the outcomes of primary ACLR in level 1 athletes and identify pre- and intraoperative factors associated with RTP, ipsilateral ACL reinjury, contralateral ACL injury, and International Knee Documentation Committee (IKDC) score at 5 years postoperatively.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A consecutive cohort of 1432 patients who underwent primary ACLR by 2 orthopaedic surgeons were prospectively evaluated. The RTP rate, incidence of ipsilateral/contralateral ACL injury, and IKDC score were analyzed at 5 years. Comparative analysis of clinical variables was performed between those who achieved favorable outcomes and those who did not. Outcomes at 5 and 2 years were also compared.

RESULTS

The mean age was 24.3 ± 7.3 years (males: 75%, females: 25%). Gaelic football was the predominant sport (40%), followed by soccer (19%). The RTP rate was 87.4%, with 59.8% of athletes still playing at an equivalent or higher level at 5 years. The incidence of ipsilateral reinjury for athletes who resumed level 1 sport was 4.3% for bone-patellar tendon-bone (BPTB) autografts with screw fixation and 19.7% for hamstring tendon (HT) autografts with EndoButton and screw fixation. The incidence of contralateral ACL injury was 13.7%. The mean IKDC score at 5 years (86.6 ± 10.9) was comparable to that at 2 years (86.8 ± 10.1). Patients were more likely to RTP with each year of decreasing age (OR, 1.06; P < .001), with a higher preoperative Marx score (OR, 1.08; P < .001) or a higher 5-year IKDC score (OR, 1.06; P < .001). The risk of ipsilateral ACL reinjury increased each year of decreasing age (OR, 1.11; P < .001) or when an HT autograft was used (OR, 5.56; P < .001). Younger age was also associated with contralateral ACL injury (OR, 1.1; P < .001). Female sex, older age, concomitant meniscal/chondral injuries, and lower preoperative Anterior Cruciate Ligament Return to Sport after Injury scores were associated with lower IKDC scores at 5 years.

CONCLUSION

Most patients could return to level 1 sports, although their performance level was impacted. Those who returned to sport maintained their performance level over the 5 years. The ipsilateral reinjury rate for BPTB autografts with screws was significantly lower than that for HT autografts with EndoButton and screw fixation. Most ACL reinjuries occurred between 2 and 5 years of follow-up. Younger patients had an increased risk of a subsequent ACL injury to either knee, regardless of graft type. IKDC scores were lower in female patients, older patients, and those with concomitant meniscal/cartilage injuries.

REGISTRATION

NCT02771548 (ClinicalTrials.gov identifier).

Revision Anterior Cruciate Ligament Reconstruction: Surgeon-Reported Causes of Failure From the Norwegian Knee Ligament Register

BACKGROUND

Failed anterior cruciate ligament reconstruction (ACLR) leads to reduced quality of life and sometimes the need for repeat surgery. The reason for failure can be multifactorial and difficult to determine. Reports on failure leading to revision are few with limited generalizability. Also, no studies have investigated the reasons for early (<2 years) versus late (≥2 years) revision.

PURPOSE

To describe patients undergoing revision surgery, the surgeon's reported cause of failure, and the risk of undergoing early versus late revision surgery.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Primary ACLR cases without concomitant ligament injuries or surgery, registered in the Norwegian Knee Ligament Register from 2004 throughout 2023, were eligible. Descriptive analyses were conducted on intraoperative findings and procedures, time from injury to surgery, activity at the time of injury, revision surgery, surgeon-reported cause of revision, and reporting method. The Kaplan-Meier method was used to calculate revision rates. A multivariable Cox regression model, adjusted for confounders, was used to calculate the hazard ratio of early and late revision surgery.

RESULTS

A total of 30,035 primary ACLR cases were analyzed, of which 1599 resulted in revision surgery. The overall revision rate was 7.1% at 15 years. Female patients were younger at the time of both primary and revision surgery (23.8 and 22.5 years, respectively) compared with male patients (28.2 and 22.2 years, respectively). Age at the time of primary surgery was significantly lower for patients who underwent revision (20.4 years) compared with those who did not undergo revision (26.5 years). Male sex, lower age, hamstring tendon graft, and no cartilage injury at the time of primary reconstruction were all associated with a higher risk of early revision. Lower age, hamstring tendon graft, and no meniscal injury were associated with a higher risk of late revision. New trauma (38.1%) was found to be the most common cause of failure leading to revision.

CONCLUSION

In the current study, representing one of the largest cohorts to date investigating failed primary ACLR leading to revision, the overall 15-year revision rate was estimated as 7.1%. Patients receiving hamstring tendon grafts were at a particular risk for early revision during the first 2 years after primary reconstruction. New trauma was the most common reported cause of failure leading to revision ACLR.

Anterior Cruciate Ligament Injury Does Not Increase the Risk for a Future Concussion: A Unidirectional Phenomenon

CONTEXT

Epidemiological studies have shown an increased risk of musculoskeletal injury after concussion. The purpose of this study was to determine whether the reverse relationship exists, specifically whether there is an increased risk of concussion after an anterior cruciate ligament (ACL) injury in a population-based cohort.

DESIGN

Retrospective cohort.

METHODS

The Rochester Epidemiology Project was searched between 2000 and 2017 for International Classification of Diseases, 9th and 10th Revision codes relevant to the diagnosis and treatment of concussion and ACL tear. A total of 1294 unique patients with acute, isolated ACL tears and no previous history of concussion were identified. Medical records for cases were reviewed to confirm ACL tear diagnosis and to determine history of concussion after the ACL injury. Cases were matched by age, sex, and Rochester Epidemiology Project availability to patients without an ACL tear (1:3 match), resulting in 3882 controls. Medical records of matched control patients were reviewed to rule out history of ACL injury. The hazard ratio of concussion injury following an ACL injury was determined.

RESULTS

Nine patients with an ACL injury suffered concussion up to 3 years after the ACL injury. The rate of concussion was no different between ACL-injured cases (0.7%) compared with matched controls with no ACL injury (1.2%), which corresponded to a hazard ratio of 0.55 (95% confidence interval, 0.3-1.1; P = .10).

CONCLUSIONS

Based on the current evidence, there does not appear to be a significant association between ACL injury and subsequent concussion, which suggests that a concussion uniquely affects the risk of future subsequent musculoskeletal injury.

Are Women Less Likely to Return to Sport Compared to Men Following Hip Arthroscopy. A Systematic Review and Meta-analysis

OBJECTIVE: To compare return-to-sport outcomes between females/women/girls and males/men/boys undergoing hip arthroscopy and explore social and structural determinants of health that may influence return to sport. DESIGN: Systematic review with meta-analysis. LITERATURE SEARCH: CINAHL, Cochrane Central Register of Controlled Trials, Embase, Medline, SPORTDiscus, and Web of Science from inception to February 2024. STUDY SELECTION CRITERIA: Studies were included if they assessed return to sport after hip arthroscopy and analyzed the influence of sex/gender on return-to-sport outcomes, or reported sex- or gender-stratified return-to-sport rates. DATA SYNTHESIS: We used a random effects model to calculate pooled odds ratios and conducted meta-regressions to compare return-to-sport outcomes between females/women/girls and males/men/boys. RESULTS: Forty-five studies were included, with all pooled results deemed as very low-certainty evidence. Compared to males/men/boys, females/women/girls had inferior return to sport at the same or higher level between 1 and 3 years postoperatively (pooled OR = 0.53; 95% CI: 0.34, 0.81; P = .004), and at any level of sport at >3 years postoperatively (pooled OR = 0.46; 95% CI: 0.25, 0.86; P = .014). Sports participation decreased over time, with ~5.5% to 10% lower proportions observed in females/women/girls compared to males/men/boys. The reporting of determinants of returning to sport was minimal, precluding further exploration of their effects. CONCLUSION: Females/women/girls had lower odds of return to sport, especially during longer follow-up periods, than males/men/boys. The lack of reporting of social and structural determinants of health influencing return-to-sport outcomes makes the reasons for this disparity unclear. J Orthop Sports Phys Ther 2025;55(3):1-13. Epub 10 February 2025. doi:10.2519/jospt.2025.12813.

High Return to Competition Rate After On-Field Rehabilitation in Competitive Male Soccer Players After ACL Reconstruction: GPS Tracking in 100 Consecutive Cases

Background

Despite published guidelines describing on-field rehabilitation (OFR) frameworks for soccer, available evidence for practitioners who work with players with anterior cruciate ligament reconstruction (ACLR) is limited.

Purpose

To document the activity and workloads completed by a large cohort of amateur and professional soccer players during OFR following ACLR after completing their indoor rehabilitation and to establish their return to competition (RTC) outcomes.

Study Design

Case series; Level of evidence, 4.

Methods

OFR measurements/activities, global positioning system (GPS), and heart rate data were collected from 100 male 11-a-side soccer players with ACLR undergoing a criteria-based rehabilitation process, concluding with a 5-stage OFR program. Consent was obtained directly from the players involved in this study before completing a follow-up questionnaire to document RTC outcomes. Differences between the level of play (professional and amateur) and 5 OFR stages were investigated using separate linear mixed models.

Results

A minimum 9-month follow-up was possible for 97 players (97%), with a median time of 2.3 years after ACLR and 84% RTC, with higher rates in professionals (100%) than amateurs (80%). Ten (10%) players sustained an ACL reinjury. Professionals completed more OFR sessions (20.6 ± 7.7 vs 13.2 ± 7.7; P < .001) over a shorter period (44.7 ± 30.3 vs 59.3 ± 28.5 days; P = .044) and achieved higher workloads mostly in the high-intensity GPS metrics in each OFR stage. Typical external workload outputs in the final OFR stage aligned with team training demands for the total distance (TD) (106%), high-intensity distance (HID) (104%), peak speed (PS) (88%), acceleration distance (ACC) (110%), and deceleration distance (DEC) (48%), but they were lower compared with match play demands (TD: 44%; HID: 51%; PS: 82%; ACC: 63%; and DEC: 26%).

Conclusion

High RTC rates were reported in those players who participated in OFR after indoor rehabilitation. Completion of all five OFR stages almost prepared them for team training demands; however, workloads remain low compared to match play.

The effect of cognitive task and gait speed on gait spatiotemporal parameters in athletes with anterior cruciate ligament reconstruction: Cross-sectional study

BACKGROUND

Restoring pre-injury normal gait following Anterior Cruciate Ligament Reconstruction (ACLR) is a critical challenge. The purpose of this study was to compare spatiotemporal parameters in athletes following ACL reconstruction with healthy athletes when cognitive load and speed were manipulated.

METHODS

Twenty male soccer players with an ACLR history and 20 healthy matched individuals completed walking tasks under four conditions: with and without a cognitive load (auditory Stroop task), and at preferred speed as well as high speed (20% higher than the individual's preferred speed). Step Width (SW), Step Time (ST), Step Length (SL), as well as Symmetry Indexes (SIs) were measured using three-dimensional (3D) motion analysis. Gait symmetry was evaluated by SIs. The data was analyzed using Three-way analysis of variances with repeated measures (ANOVA 3 × 2).

RESULTS

ST was significantly different between groups (P = 0.04) when the cognitive load was applied at the preferred speed. However, other spatiotemporal parameters were not significantly different between groups in any conditions (p > 0.05). The SW was reduced during high-speed walking with cognitive load in both groups (p = 0.004). High-speed resulted in greater SL (p < 0.001) and lower ST (p < 0.001) in both groups. SI was not significantly different for any parameter between groups under any conditions, however, the interaction of cognitive task × speed was significant for SW (p = 0.03).

CONCLUSION

Athletes at a mean of 19 months following ACL Reconstruction appear to manage speed and cognitive challenges similar to age and activity matched individuals who have not had surgery.

Return to On-Snow Performance in Ski Racing After Anterior Cruciate Ligament Reconstruction

BACKGROUND

The individual variation in on-snow performance outcomes after anterior cruciate ligament (ACL) reconstruction (ACLR) in elite alpine ski racers has not been reported and may be influenced by specific injury characteristics.

PURPOSE

To report the performance statistics of elite ski racers before and after ACLR and to identify surgical and athlete-specific factors that may be associated with performance recovery.

STUDY DESIGN

Descriptive epidemiological study.

METHODS

International Ski and Snowboard Federation (FIS) points, FIS ranking, average placing, and average percentage behind the winning time in each race were calculated for 30 national and provincial team ski racers at 1 year before and 3 years after ACLR. Injury characteristics were obtained from operative reports and clinical notes.

RESULTS

The mean age at the time of primary ACLR was 21.6 ± 3.5 years. Overall, 27 of 30 (90%) ski racers returned to the same preinjury competition level. Yet, only 16 of 30 (53%) improved in FIS points, and 13 of 30 (43%) improved in FIS ranking, in one of the speed or technical disciplines by 3 years after surgery. Of the skiers who improved in FIS points, 36% sustained multiligamentous injuries, 45% sustained meniscal tears, and 45% sustained chondral lesions. Of those who failed to improve in FIS points, 50% sustained multiligamentous injuries, 50% sustained meniscal tears, and 60% sustained chondral lesions. Meniscal tears and chondral lesions occurred mostly on the lateral side. The medial collateral ligament was involved in 8 of 9 multiligamentous injuries.

CONCLUSION

These findings suggest significant individual variation in the recovery of on-snow performance of ski racers after ACLR, despite returning to the same competition circuit. The pattern of secondary injuries alongside primary ACL ruptures showed little association with improved performance.

Sex Differences in Quadriceps Atrophy After Anterior Cruciate Ligament Tear

BACKGROUND

Female athletes lag behind their male counterparts in recovery from anterior cruciate ligament (ACL) injury. Quadriceps muscle size and strength are crucial factors for regaining function after ACL injury, but little is known about how these metrics vary due to biological sex.

HYPOTHESIS

Female patients have reduced vastus lateralis fiber cross-sectional area (CSA) and lower quadriceps strength after ACL injury than male patients.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 4.

METHODS

A total of 60 participants with recent ACL tear were evaluated for vastus lateralis muscle fiber CSA, isometric quadriceps peak torque, and quadriceps rate of torque development. Linear mixed models were fit to determine differences across sex and limb for each variable of interest.

RESULTS

The female group averaged almost 20% atrophy between limbs (P < 0.01), while the male group averaged just under 4% (P = 0.05). Strength deficits between limbs were comparable between female and male groups.

CONCLUSION

Immediately after ACL injury, female patients have greater between-limb differences in muscle fiber CSA but between-limb strength deficits comparable with those of male patients.

CLINICAL RELEVANCE

These results indicate that the underpinnings of strength loss differ based on biological sex, and thus individual patients could benefit from a sex-specific treatment approach to ACL injury.

Surgical Stabilization Results in Superior Clinical Outcome, Lower Recurrent Instability, and Reduced Risk of Meniscal Tears Relative to Nonoperative Treatment of ACL Rupture: A 3-Year Prospective Controlled Cohort Study

Background

There has been renewed interest in nonoperative treatment of anterior cruciate ligament (ACL) rupture following research suggesting that some ACL ruptures can heal naturally. However, the research is based on magnetic resonance imaging grading of ACL injuries rather than clinical signs, and the accuracy of the grading system is unknown. Nonoperative treatment of ACL ruptures has been associated with a higher risk of meniscal tears and recurrent instability, both of which may have long-term implications for the knee in terms of degeneration and the need for more complex stabilization surgery. More research into the nonoperative management of clinically significant ACL injuries is indicated before consideration for use in clinical practice.

Hypothesis

Operative management of ACL rupture improves clinical outcome relative to nonoperative management.

Study Design

Cohort study; Level of evidence, 3.

Methods

The Covid-19 pandemic temporarily stopped elective surgery during 2020. For 2 months, those patients with isolated ACL ruptures underwent nonoperative treatment with bracing and physical therapy (Nonop group) were compared with a matched cohort undergoing ACL reconstruction (ACLR group) immediately before this period. Groups were compared at baseline with regard to age, gender, body mass index (BMI), lateral posterior tibial slope (LPTS), and the following patient-reported outcome measures (PROMs)-Tegner Activity Scale (TAS), International Knee Documentation Committee (IKDC), Sport and Recreation subscale (Sport/Rec) of the Knee injury and Osteoarthritis Outcome Score (KOOS), Knee Related Quality of Life (KR QoL) subscale of the KOOS, and Lysholm Knee Score (LKS)-as well as recurrent instability and meniscal tears, over a period of 3 years. Pearson chi-square test and analysis of variance were used for baseline characteristics, generalized linear models and multivariate tests for changes in PROMs, and chi-square tests for meniscal tears and recurrent instability. Statistical significance was accepted at P < .05.

Results

A total of 82 patients were recruited, 41 in each group. The ACLR group and the Nonop group were similar with regard to all baseline variables, with the following mean ± SD values, respectively: age in years (22.1 ± 3.8 vs 21.3 ± 3.4; P = .23), BMI in kg/m2 (21.0 ± 2.0 vs 20.4 ± 2.5; P = .39), LPTS (8.1° ± 1.3° vs 7.9° ± 2.0°; P = .65), and preinjury TAS (8.2 ± 1.1 vs 8.7 ± 1.0; P = .33). The male:female ratio was 15:26 vs 17:24 (P = .71), respectively. At 3-year follow-up, the ACLR group had greater improvement in all PROMs than the Nonop group: TAS, 8.0 ± 1.0 vs 5.5 ± 0.9; IKDC, 90.9 ± 3.8 vs 65.0 ± 8.1; Sport/Rec, 92.4 ± 7.6 vs 66.6 ± 6.1; KR QoL, 91.1 ± 5.5 vs 74.3 ± 6.6; and LKS, 92.2 ± 4.9 vs 66.9 ± 6.1, respectively (all P < .001). There was a lower risk of both recurrent instability (5% vs 88%; P < .001) and medial meniscal tears (5% vs 63%; P < .001).

Conclusion

ACLR results in a highly statistically significantly better clinical outcome than nonoperative management of ACL rupture in terms of PROMs, as well as a lower risk of both recurrent instability and meniscal tears, over a period of 3 years.

Patients undergoing multiligament knee reconstruction injured during pivoting sports demonstrate similar clinical, functional and return to sport outcomes by 2 years compared with those undergoing anterior cruciate ligament reconstruction

PURPOSE

This study investigates the clinical and activity-based outcomes after anterior cruciate ligament reconstruction (ACLR) versus multiligamentous knee reconstruction (MLKR) following a pivoting sports injury.

METHODS

Fifty MLKR patients were included, of which 20 (40%) were injured during pivoting sports. A further 50 patients undergoing ACLR following an injury during pivoting sports were consecutively recruited for comparison. Patients were assessed before the surgery and at 6-, 12- and 24 months with patient-reported outcome measures (PROMs) including the International Knee Documentation Committee (IKDC) form, Tegner activity scale (TAS) and anterior cruciate ligament return to sport after injury (ACL-RSI) score. Knee movement, the single (SHD) and triple (THD) hop tests for distance, and peak isokinetic knee extensor and flexor strength were assessed, with Limb Symmetry Indices (LSIs) calculated. Outcomes were compared across groups: (1) ACLR (n = 50), (2) MLKR (n = 50) and (3) MLKR due to pivoting sport injury (n = 20).

RESULTS

IKDC, TAS and ACL-RSI scores remained lower (p < 0.05) in the full MLKR versus ACLR cohort at all timepoints. Comparing the ACLR and MLKR cohort that had injuries specifically during pivoting sports, the IKDC (p < 0.001) and TAS (p = 0.009) were higher in the ACLR group at 6 months, and the ACL-RSI was higher at 6 (p < 0.001) and 12 (p = 0.007) months, there were no further differences. Hop and knee extensor strength LSIs were lower (p < 0.05) in the full MLKR (versus ACLR) cohort at all timepoints (apart from the 24-month SHD LSI). However, the ACLR group only demonstrated greater LSIs than the pivoting sport MLKR for the SHD at 6 months (p < 0.001), and knee extensor strength at 6 (p < 0.001) and 12 (p < 0.001) months.

CONCLUSIONS

While the recovery of patients undergoing MLKR due to a pivoting sports injury is delayed compared with their ACLR counterparts, the clinical outcome and activity profile are similar by 24 months.

LEVEL OF EVIDENCE

Level IV.

How Does Physical and Psychological Recovery Vary Among Competitive and Recreational Athletes After Anterior Cruciate Ligament Reconstruction?

BACKGROUND

The recovery and rehabilitation journey after anterior cruciate ligament reconstruction (ACLR) surgery can be different for competitive and recreational athletes as their motivation and goals toward sports are different.

HYPOTHESIS

Competitive athletes would present with better patient-reported outcomes and higher muscle strength compared with recreational athletes postsurgery. Second, competitive athletes would recover better (patient-reported outcome [PRO] measures and muscle strength) compared with recreational athletes at later stages.

STUDY DESIGN

Cross-sectional laboratory-based study.

LEVEL OF EVIDENCE

Level 2.

METHODS

A total of 245 patients with unilateral ACLR were categorized as competitive or recreational athletes and grouped into early (4-6.9 months) or late (7-10 months) stages of recovery. PRO were collected for psychological response (Tampa Scale Kinesiophobia; Anterior Cruciate Ligament-Return to Sport after Injury), perceived knee function (International Knee Documentation Committee subjective form [IKDC]), and quality of life (Knee injury and Osteoarthritis Outcome Score; Veteran Rand-12). Isokinetic, concentric knee extension strength was measured bilaterally with a multimodal dynamometer (System 4, Biodex Medical Systems) at a speed of 90° and 180°/s.

RESULTS

Competitive athletes had significantly higher scores for IKDC (P = 0.03), and quadriceps peak torque at 90°/s (P = 0.01) and 180°/s (P < 0.01) compared with recreational athletes. Competitive athletes had higher quadriceps strength at 90°/s (P < 0.01) and 180°/s (P = 0.02) in the late group. Recreational athletes displayed higher sports participation in the late group.

CONCLUSION

Outcomes of ACLR may differ based on preinjury athletic level. Whereas competitive athletes had higher knee and muscle function than recreational athletes, psychological measures were not different among groups.

CLINICAL RELEVANCE

There is a need for more individualized care for patients with ACLR since there is variability among patient goals postsurgery. This information might help set realistic expectations for competitive and recreational athletes after surgery.

Effects of augmented feedback on landing mechanics after anterior cruciate ligament reconstruction in collegiate females compared to healthy controls

OBJECTIVE

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.

DESIGN

Cross-sectional cohort study.

SETTING

Motion Laboratory.

PARTICIPANTS

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

MATERIALS AND METHODS

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

MAIN OUTCOME MEASURES

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

RESULTS

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.

CONCLUSIONS

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.

Cartilage Deformation, Outcomes, and Running Force Comparisons in Females With and Without Knee Injuries

CONTEXT

Anterior cruciate ligament reconstruction (ACLR) is a known risk factor for knee osteoarthritis (OA). Since no disease-modifying treatments for OA exist, it is critical to understand joint responses to physical activity following an ACLR. Understanding knee cartilage deformation through ultrasound may provide a better understanding of how knee cartilage responds to running, and how this may contribute to OA pathophysiology and risk.

OBJECTIVE

To compare medial femoral cartilage deformation, outcomes, and forces during running in females with and without a unilateral ACLR knee.

DESIGN

Cross-sectional laboratory study.

METHODS

Sixteen females (8 ACLR history, 8 controls) participated. ACLR participants had an average age of 20.75 (1.83) years, height of 165.07 (7.43) cm, mass of 65.97 (8.55) kg, and were 36.13 (18.74) months postsurgery; controls had an average age of 20.62 (1.84) years, height of 166.00 (5.76) cm, and mass of 63.18 (4.94) kg. Independent variables were group and limb, with dependent variables including patient reported outcomes Knee Injury and Osteoarthritis Outcome Score (KOOS), medial femoral cartilage thickness changes, and indirect measures of stance-averaged vertical ground reaction forces and vertical rate of loading normalized to body weight during treadmill running. Data were analyzed using nonparametric statistics with significance defined as P ≤ .05.

RESULTS

All participants exhibited cartilage thickness reduction after 30 minutes of running (P < .001), with no significant group or limb differences in cartilage deformation, vertical ground reaction forces, or vertical rate of loading. ACLR participants reported significantly poorer patient reported outcome scores across all KOOS subscales. Moderate negative correlations were found between involved cartilage percent change and KOOS Symptoms (P = .025) and Sport/Rec (P = .043).

CONCLUSIONS

Cartilage thickness significantly decreased in all participants after running, with no group or limb differences observed despite lower patient-reported outcomes in the ACLR group. Exploring the relationship between KOOS scores and cartilage response to activity may inform future research and strategies to mitigate OA risk.

Risk Factors for Venous Thromboembolism (VTE) Following Anterior Cruciate Ligament (ACL) reconstruction: A systematic review and meta-analysis

BACKGROUND

Thromboembolism (VTE) is an uncommon, but potentially serious complication in patients who undergo anterior cruciate ligament (ACL) reconstruction.

PATIENTS AND METHODS

PubMed, EMBASE, and Cochrane databases were searched for relevant studies published until July 16, 2023. Eligible studies were those investigating patients who were undergoing ACL reconstruction, with the primary focus on factors associated with VTE including age, sex, body mass index (BMI), hypertension, smoking, type of surgical setting (outpatient vs. inpatient), and tourniquet time.

RESULTS

Six studies consisted of a total of 47,886 patients underwent ACL reconstruction were included. The VTE rate ranged between 0.4% and 11.0%, and the mean patient age ranged from 26.8 to 33.25 years. The meta-analysis revealed no significant association between VTE risk and sex (pooled adjusted odds ratio [aOR] = 1.28, 95% confidence interval [CI]: 0.88-1.85). Furthermore, the meta-analysis showed a significantly higher risk of VTE in smokers compared to non-smokers, favoring non-smokers (pooled aOR = 1.71, 95% CI: 1.16-2.54). The systematic review identified several other potential factors, including older age, BMI, hypertension, smoking, surgical setting, and tourniquet time, which were documented in at least 2 included studies. However, while some of these factors showed reported significance, the number of studies was insufficient to generate a pooled result.

DISCUSSION

According to our meta-analysis, sex does not appear to be a significant risk factor for VTE in patients undergoing ACL reconstruction. However, more evidence is needed to determine whether factors such as older age, BMI, hypertension, outpatient vs. inpatient surgery, and tourniquet time are associated with increased VTE risk. Caution is still advised when managing patients with these risk factors in the context of ACL reconstruction. A future meta-analysis is warranted once a sufficient number of studies are available to draw more definitive conclusions.

LEVEL OF EVIDENCE

IV.

'The right advice': a qualitative study examining enablers and barriers to recreational running and beliefs about knee health following knee surgery

OBJECTIVES

To examine the experiences, knowledge and beliefs of recreational runners with a history of knee surgery regarding (i) enablers and barriers to running participation, (ii) the association of running and knee joint health, and (iii) perceived benefits and motivations for running.

METHODS

17 runners (≥3 times/week, ≥10 km/week) with a history of knee surgery (7±7 years post-surgery, 9 women, age 36±8 years) participated in one-on-one semi-structured interviews. Interviews were recorded, transcribed verbatim and analysed using reflexive thematic analysis. Trustworthiness was built by following established qualitative research guidelines and by participant validation of findings in the final analysis stages.

RESULTS

We identified 9 themes (5 subthemes) for aim (i); 3 themes (10 subthemes) for aim (ii); and 2 themes (4 subthemes) for aim (iii). Positive health professional support including education, exercise rehabilitation and a tailored return-to-run plan enabled participants to return to running following surgery. Effective load management either independently or with coach assistance, and consistent strength training were considered key to maintaining participation. Barriers to running following surgery included unhelpful health professional encounters, persistent knee symptoms and muscle weakness, new running-related injuries, anxiety and fear about reinjury, and difficulty finding time. Participants had varying beliefs about running and knee joint health, although most believed that running benefited long-term knee health. Improved mental health and social connection were the most common motivators to run.

CONCLUSION

Our qualitative findings may inform strategies to support adults to commence, or return to, and maintain running participation following knee surgery.

Head, Hands, Knees and Ankles, Knees and Ankles: Injury Profiles of Women and Girls Playing Community Australian Football

BACKGROUND

Women's participation in all football codes (including Australian Football [AF]) is increasing rapidly. To guide injury prevention strategies, the authors aimed to describe the current and lifetime prevalence of significant musculoskeletal injuries and concussions for women and girls playing community AF.

HYPOTHESIS

Women will have high rates of injury associated with playing AF.

STUDY DESIGN

Cross-sectional survey.

LEVEL OF EVIDENCE

Level 3.

METHODS

Participants were Victorian community AF players from 165 participating teams (<16 years, <18 years, senior women's). Demographics, injury prevalence, and health outcomes are reported descriptively. To explore relationships between sociodemographic factors and anterior cruciate ligament (ACL) injury history, the authors fitted univariate logistic regression models. Independent variables were age, body mass index, number of career AF games, sport experience, location (metropolitan/regional), and socio-economic index.

RESULTS

A total of 2435 players (95% of players enrolled in the trial), aged 24 ± 7 years completed the survey. One-quarter (n = 619, 25%) reported a current injury, and half (n = 1238, 51%) reported a previous significant injury. The most common injury sites were knee (n = 160 26% current, n = 403 33% previous), ankle (n = 130 21% current, n = 427 35% previous), and hand/fingers (n = 100 16% current, n = 317 26% previous). Self-reported previous ACL injury (n = 139, 6%) and concussion (n = 1335, 55%) were also prevalent. Increasing age (odds ratio [OR], 1.07; 95% CI, 1.05-1.09) and more career games (OR, 2.22; 95% CI, 1.24-3.97) were associated with ACL injury history.

CONCLUSION

Women and girls playing community AF reported high rates of significant injury. Injury prevention programs should target the most prevalent injury sites: head (concussion), ankle, knee, and hand/fingers.

CLINICAL RELEVANCE

These findings highlight high injury rates for women playing AF and will be invaluable in shaping injury prevention strategies.

The Impact of a Concomitant Meniscus Surgery on Hop Performance Symmetry in Patients Rehabilitating After Anterior Cruciate Ligament Reconstruction

Background

Meniscus injuries often accompany anterior cruciate ligament (ACL) tears. However, little is known about how different surgical approaches to treat concomitant meniscus injuries impact hop performance after ACL reconstruction. Purpose: The purpose of this study was to compare hop test inter-limb symmetry for patients who had undergone ACL reconstruction without an associated meniscal surgery, patients who had undergone ACL reconstruction with a meniscus repair, and patients who had undergone ACL reconstruction with a partial meniscectomy.

Study Design

Cross-sectional study.

Methods

Hop test data collected at the time of return-to-sport testing (average of 6.4 ± 1.4 months after surgery) was extracted from electronic medical records for 192 patients who had undergone ACL reconstruction. Of these patients, 102 had undergone an isolated ACL reconstruction, 60 had undergone an ACL reconstruction along with a meniscus repair, and 30 had undergone an ACL reconstruction along with a partial meniscectomy. Analysis of variance was used to compare limb symmetry indices for the single- and triple-hop tests. These limb symmetry indices reflected the ratio of the hop distance for the involved limb relative to the uninvolved limb, expressed as a percentage.

Results

The sample was comprised of 100 males and 92 females. Their average age was 20.6 ± 8.2 years. There were significant differences among the groups for the single-hop test (p = 0.031) and triple-hop test (p = 0.024) limb symmetry indices. For both tests, the patients who had undergone ACL reconstruction with a partial meniscectomy tended to exhibit greater deficits in hop performance for their involved limb (relative to their uninvolved limb), compared to those without a meniscal injury and those who had undergone meniscus repair.

Conclusions

The results of this study suggest that patients who undergo ACL reconstruction along with a partial meniscectomy tend to experience less complete and/or delayed recovery of involved-limb hop performance, which could reflect more persistent deficits in lower body power.

Level of Evidence

3.

Hamstrings and Quadriceps Weaknesses Following Anterior Cruciate Ligament Reconstruction Persist Up to 6 Months After Return-to-Sport: An Angle-specific Strength Analysis

BACKGROUND

Hamstrings and quadriceps strength recovery and restoration of the hamstrings-to-quadriceps ratio (H/Q ratio) is a major concern after anterior cruciate ligament reconstruction (ACLR). Recently, moment-angle profiles and angle-specific H/Q ratios are receiving increasing interest.

PURPOSE

The first objective of this study was to investigate moment-angle profiles and angle-specific H/Q ratio profiles in athletes with ACLR at the time of RTS. The second objective of this study was to assess whether strength asymmetries identified at the time of RTS, persist after six months.

STUDY DESIGN

Case-Control study.

METHODS

Twenty athletes who had undergone ACLR performed isokinetic strength tests for concentric knee flexion and extension (60°/s) at RTS, and three and six months later. Twenty controls were tested once. T-tests were used to compare strength differences between 1) ACLR athletes and controls and 2) the injured and uninjured leg of the ACLR athletes. Finally, to assess strength deficits over time, two-way ANOVAs were used.

RESULTS

Angle-specific analyses and peak moments showed lower hamstrings strength in the injured leg of ACLR athletes compared to their uninjured leg at RTS. Furthermore, angle-specific analyses showed a lower hamstrings strength and H/Q ratio in the injured leg compared to controls at larger knee flexion angles. The latter deficit was not identified with a peak-based analysis. The asymmetries identified at RTS did not change over the six months following RTS.

CONCLUSIONS

Athletes with ACLR show strength deficits and asymmetries that persist even six months after RTS. As some asymmetries may go undetected by peak-based analyses, angle-specific analyses are recommended.

LEVEL OF EVIDENCE

Level 3b.

The Efficacy of Blood Flow Restriction Training to Improve Quadriceps Muscle Function after Anterior Cruciate Ligament Reconstruction

BACKGROUND

Blood flow restriction training (BFRT) is a popular rehabilitation intervention after anterior cruciate ligament reconstruction (ACLR). However, there are a lack of clinical trials establishing the efficacy of using BFRT during rehabilitation to improve quadriceps muscle function.

PURPOSE

The purpose of this study is to evaluate the efficacy of blood flow restriction training to improve quadriceps muscle strength, morphology, and physiology, and knee biomechanics in individuals after ACLR in a double-blind, randomized, placebo-controlled clinical trial (NCT03364647).

METHODS

Forty-eight athletes (20 females/28 males) were randomly assigned to low-load strength training with active BFRT or standard of care strength training with a sham unit. Treatment occurred for 1-month pre-surgery and 4 to 5 months post-surgery with both groups following the same standard rehabilitation protocol. Outcome variables were measured at baseline and 4 to 5 months post-surgery. Quadriceps muscle strength (isometric and isokinetic peak torque and rate of torque development) was measured on an isokinetic dynamometer. Quadriceps muscle morphology (physiological cross-sectional area, fibrosis) was determined using magnetic resonance imaging. Quadriceps muscle physiology (fiber type, fiber cross-sectional area, satellite cell abundance, collagen content, fibrogenic/adipogenic progenitor cells) was evaluated with muscle biopsies of the vastus lateralis. Knee extensor moment and knee flexion angle were measured via three-dimensional gait analysis. Change scores were calculated as: post-intervention - baseline. Two-sample t -tests were then used to assess between-group differences for each outcome variable.

RESULTS

No significant between-group differences were found for any outcome variable.

CONCLUSIONS

The addition of BFRT to a rehabilitation program for athletes pre- and post-ACLR was no more effective than standard rehabilitation for improving quadriceps muscle function. Clinicians should consider the value of BFRT relative to the cost, time, and discomfort for patients in light of these results.

The Neuroplastic Outcomes from Impaired Sensory Expectations (NOISE) hypothesis: How ACL dysfunction impacts sensory perception and knee stability

BACKGROUND

The anterior cruciate ligament (ACL) is integral to maintaining knee joint stability but is susceptible to rupture during physical activity. Despite surgical restoration of passive or mechanical stability, patients struggle to regain strength and prior level of function. Recent efforts have focused on understanding how ACL-related changes in the nervous system contribute to deficits in sensorimotor control following injury and reconstruction. We hypothesize that these challenges are partially due to an increase in sensorimotor uncertainty, a state that reduces the precision of movement control.

OBJECTIVES

This review proposes the ACL NOISE (Neuroplastic Outcomes from Impaired Sensory Expectations) hypothesis, reframing current literature to provide a case that increased sensory noise following ACL injury and reconstruction disrupts sensory predictions, which are anticipations of immediate sensory outcomes or motor commands. This disruption in sensory predictions may contribute to altered neurophysiology, such as cross-modal brain activity, and other persistent clinical deficits.

DESIGN

Narrative review RESULTS/FINDINGS: Following ACL injury and reconstruction, the knee and nervous system experience various neurophysiological alterations to overcome elevated sensory uncertainty and inaccurate sensory predictions, contributing to persistent motor deficits.

CONCLUSIONS

We provide a theoretical case based on compelling evidence that suggests prolonged impairment after ACL injury may be secondary to uncertainty in knee sensory perception. Future research should consider testing the NOISE hypothesis by creating a paradigm that examines dynamic joint stability in response to unexpected perturbations. This approach would help assess motor coordination errors and drive the development of clinical strategies aimed at reducing sensory uncertainty following ACL reconstruction.

Strength Setbacks: The Impact of Youth Sport-Related Knee Joint Injuries on Thigh Muscle Strength. A 24-Month Prospective Cohort Study

OBJECTIVE: To compare injured and uninjured limb knee extensor and flexor peak torque between youth who experienced a sport-related, traumatic knee joint injury and comparable uninjured youth, at baseline (≤4 months of injury) and semiannually for 2 years. Differences by injury type and sex were also explored. DESIGN: Prospective cohort study. METHODS: Bilateral knee extensor and flexor concentric isokinetic peak torque at 90° per second was assessed semiannually in 186 youth (106 injured, 80 controls) for 2 years. Between-group differences in strength over time were estimated with generalized estimating equations (95% confidence interval [CI]). Confounding was controlled using inverse probability weighting. Strength differences between those with anterior cruciate ligament (ACL) tears and those with non-ACL tear injuries as well as between male and female participants were explored. RESULTS: Compared to uninjured controls, injured limb knee extensor strength was lowest at baseline (-37.1 Nm; 95% CI, -45.3 to -28.9) and 6-month follow-up (-13.3 Nm; 95% CI, -20.4 to -6.2), with minimal strength gain beyond the 12-month follow-up (1.7 Nm; 95% CI, -14.3 to 17.6). Knee flexor strength of the injured limb was lowest at baseline (-24.6 Nm; 95% CI, -31.5 to -17.8), and there was minimal strength gain beyond 6 months (2.3 Nm; 95% CI, -7.7 to 12.3). The average residual deficit was similar to the knee extensors (10% to 11%) at 24 months. Exploratory analysis suggested no difference based on injury type or sex. CONCLUSION: Injured limb knee extensor and flexor weakness was present after different youth sport-related knee joint injuries. Strength deficits peaked early after injury, improved over time, and plateaued after 12 months, with lingering deficits at 24 months. Thigh muscle strength trajectory was similar across injury types and sex. J Orthop Sports Phys Ther 2025;55(2):1-11. Epub 20 December 2024. doi:10.2519/jospt.2024.12663.

Reason Profiles for not Returning to Preinjury Activity Level Following Anterior Cruciate Ligament Reconstruction- A Latent Class Analysis With Subgroup Comparison of Patient-Reported Outcome Measures

Background

Given the high proportion of athletes who do not return to sports (RTS) after anterior cruciate ligament reconstruction (ACLR), strategies are needed to identify at-risk patients and optimize rehabilitation for successful RTS after ACLR.

Purpose/Hypothesis

This study used latent class analysis (LCA) to characterize a unique clustering of reasons why athletes do not return to their preinjury activity level after ACLR. We hypothesized that patients with high pain scores and high levels of fear would be less likely to return to their preinjury activity level.

Study Design

Cohort study; Level of evidence, 3.

Methods

All patients at a single institution who underwent primary ACLR between 2005 and 2021 were contacted to complete a survey via REDCap. Patients' ability to RTS and their preinjury activity level, reasons for inability to return to the preinjury activity level, and patient-reported outcome scores were collected from 981 patients. LCA was performed to identify and compare patterns among patients' reasons for not returning to the preinjury activity level.

Results

Of the 981 patients included, only 446 (45.5%) were fully able to return to their preinjury activity level. LCA categorized patients into 3 groups based on their reasons for not returning to preinjury activity levels: a high-function group (75.5%), which reported no barriers; a multisymptom group (16.1%), which cited pain, lack of strength, and instability; and a fear-limited group (8.4%), which reported fear as the sole reason. Among the high-function group, 86.2% reported RTS compared with <36.7% in the other classes. There was no difference in Knee injury and Osteoarthritis Outcome Score (KOOS) subscales-including Pain, Symptoms, or Activities of Daily Living-between the high-function and fear-limited groups; however, the multisymptom group presented with the lowest scores in all KOOS subscales (P < .001). In addition, patient characteristics, the time from the index ACLR to the follow-up, and subsequent revision ACLR were similar between groups; however, the multisymptom profile demonstrated the highest proportion of allograft ACLR (P = .04) and secondary ipsilateral surgery (P < .001). Overall subjective knee grade (1-100) and Marx scores were highest in the high-function group, followed by fear-limited and multisymptom groups (P < .001).

Conclusion

Patients were differentiated into 3 distinct classes after primary ACLR. Furthermore, those with patient-reported characteristics of pain, lack of strength, instability, or fear were significantly less likely to return to their preinjury activity level or sport.

Substantial Variability Exists in Reporting Clinically Significant Outcome Measure Thresholds for Arthroscopic Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

To systematically review the reporting of clinically significant outcome measure (CSO) thresholds and methods for calculating thresholds following anterior cruciate ligament (ACL) reconstruction.

METHODS

A systematic review of PubMed, Embase, and Web of Science databases was conducted to identify articles that met inclusion criteria from January 1, 2015, to July 7, 2024. Inclusion criteria included studies reporting CSO thresholds including minimal clinically important difference (MCID), substantial clinical benefit (SCB), or patient acceptable symptomatic state (PASS) for patients following ACL reconstruction with minimum 12-month follow-up. The MINORS criteria was used to assess study quality. Study demographics, patient-reported outcome measures (PROMs), CSO thresholds, and method of CSO calculation were collected.

RESULTS

A total of 56 studies (n=52,292 patients) met the final inclusion criteria. Reported PROMs included International Knee Documentation Committee (IKDC) (n=35 studies), Knee Injury and Osteoarthritis Outcome score (KOOS) (n=33 studies), Tegner (n=20 studies) and Lysholm (n=19 studies) scores. The PASS was reported in 35 studies, MCID in 30, and SCB in 4. Among the studies that reported PASS, the most used threshold calculation was the ROC-Youden index (71.4%, n=25/35). In the studies reporting MCID, the most used threshold calculation was the 0.5 standard deviation (SD) of mean change method (36.7%, n=11/30). The most reported threshold calculation among the SCB studies was the ROC curve analysis (75%, n=3/4). In studies independently calculating CSOs, the most common methods were 0.5 standard deviations (SD) of mean change for MCID (50%, n=10/20), the ROC-Youden index for PASS (73.3%, n=11/15), and ROC curve analysis (75.0%, n=3/4) for SCB. Descriptions of anchor questions were reported in 22 studies (39.3%).

CONCLUSION

Substantial variability exists in the reporting and calculation of MCID, SCB, and PASS for various PROMs following ACL reconstruction.

Return to competition after ACL reconstruction: Factors influencing rates and timing in Swedish football players

PURPOSE

To investigate the rate and timing for return to football league games after anterior cruciate ligament reconstruction (ACLR) in Swedish players, examining associations with sex, age, level, graft and additional ACL surgery.

METHOD

Data from the Swedish National Knee Registry (SNKLR) and the Swedish Football Association's IT System (FOGIS) were used. The study cohort comprised 971 football players, 64% males, who underwent primary ACLR. Demographics, graft type and surgical information were extracted from the SNKLR and game participation from FOGIS. Follow-up for return to competition (RTC) was conducted for 36 months, while additional ACLR follow-up was 3-7 years. Statistical analyses, including Kaplan-Meier survival curves and relative risk calculations, were employed to assess factors influencing RTC rates and timing.

RESULTS

Out of 971 players analyzed, 53% RTC within 3 years with no difference between males and females, at a mean of 15 months (median 14 months) from surgery to the first game. Eleven (2%) players RTC < 6 months from ACLR, 62 (12%) 6-9 months, 125 (24%) 9-12 months and 331 (63%) >12 months. Patellar tendon (PT) grafts demonstrated superior performance, showing quicker returns and higher RTC rates (p = 0.005) compared to hamstring (hazard ratio [HR]: 0.63 [0.48-0.84]) and quadriceps tendon grafts (HR: 0.53 [0.30-0.93]). Players competing in higher divisions pre-injury experienced significantly swifter and higher RTC rates (p < 0.001). Ninety-five (10%) had a registered additional ACLR. Players who RTC did not exhibit a significantly higher rate of revision (35 [7%] vs. 25 [5%]). However, those who returned faced a heightened risk of contralateral ACLRs compared to those who did not RTC (32 [6%] vs. 4 [1%] RR 1.72 [1.59-1.96], p < 0.001).

CONCLUSION

The study reveals that 53% of football players RTC after ACLR, predominantly after more than 12 months. The RTC was higher and faster in high-level players and those receiving a PT graft. The slow RTC may contribute to the relatively low rate of additional ACLRs.

LEVEL OF EVIDENCE

Level III.

Reasons Why Patients Do Not Return to Sport Post ACLReconstruction: A Cross-Sectional Study

Background

Patients who incur an anterior cruciate ligament (ACL) injury and undergo ACL reconstruction (ACLR) have the intention of returning to sports at their pre-injury level; however, many do not return to the pre-injury level. This study aims to investigate the common factors that hinder patients from resuming sports activities following ACLR and to assess how these barriers impact their ability to return to sports. We hypothesized that patients' psychological factors, including fear of reinjury, would significantly influence their decision to return to sport after ACL reconstruction.

Methods

In this cross-sectional study, 138 patients who had undergone ACL reconstruction surgery were examined. The research methodology involved conducting interviews to gather comprehensive data on demographic, psychological, and physical factors that impact the resumption of sports activities following ACLR. The factors considered encompassed knee-related symptoms, life-related reasons, and choice-related reasons, such as fear of reinjury.

Results

Among the 138 participants who were included, the mean age was 33.49 ± 9.19 years, with only 39 (28.3%) patients indicated a successful return to their pre-injury activity levels. The obstacles preventing the resumption of sports activities were more commonly attributed to reasons such as fear of reinjury (79.8%) and persistent knee symptoms (78.8%), rather than choice-related reasons (excluding fear of reinjury) (23.2%), such as lack of time or interest, and life-related reasons (18.2%), including work, family, and education. In addition, patients who completed the rehabilitations were 6.277 times more likely to return to the previous level of activity (95% CI 1.801-21.880; P = 0.001).

Conclusion

This research places emphasis on the impact of psychological factors, particularly the fear of reinjury, more commonly in male, on the decision to resume sports activities. In addition, persistent knee symptoms and completion of rehabilitation after ACLR is another factors contributing in returning to sport. Psychological evaluation and counseling may identify those less likely to return to sport, allowing for more targeted interventions to further improve ACLR outcomes.

Return to Sport and Graft Failure Rates After Primary Anterior Cruciate Ligament Reconstruction With a Bone-Patellar Tendon-Bone Versus Hamstring Tendon Autograft: A Systematic Review and Meta-analysis

BACKGROUND

Anterior cruciate ligament (ACL) tears are frequent injuries in athletes that often require surgical reconstruction so that patients may return to their previous levels of performance. While existing data on patient-reported outcomes are similar between bone-patellar tendon-bone (BTB) and hamstring tendon (HT) autografts, the literature regarding return to sport (RTS), return to previous levels of sport activity, and graft failure rate remains limited.

PURPOSE

To compare rates of RTS, return to previous activity levels, and graft retears among athletes undergoing primary ACL reconstruction using a BTB versus HT autograft.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

The MEDLINE, Embase, and Cochrane Library databases were queried, and studies reporting on RTS after primary ACL reconstruction using a BTB or HT autograft were included. Exclusion criteria included revision reconstruction, ACL repair, quadriceps tendon autografts, allografts, graft augmentation, or double-bundle autografts. Rates of RTS, return to previous levels of activity, and retears were extracted and analyzed across included studies.

RESULTS

A total of 33 articles met inclusion criteria, with a patient cohort of 4810 athletes. The overall RTS rate for all athletes was 80.4% (95% CI, 75.3%-84.6%) at a mean follow-up of 35.7 months, with 54.6% (95% CI, 48.5%-60.6%) returning to preinjury levels of activity. No significant difference was found between BTB and HT autografts with respect to rates of RTS, return to preinjury activity levels, or reruptures. The overall RTS rate in patients after primary ACL reconstruction with a BTB autograft was 83.3% (95% CI, 77.0%-88.2%), with 56.1% (95% CI, 49.3%-62.7%) returning to preinjury levels of activity. Conversely, the overall RTS rate in patients after primary ACL reconstruction with an HT autograft was 77.9% (95% CI, 70.3%-84.0%), with 53.5% (95% CI, 42.8%-63.9%) returning to preinjury levels of activity. The overall graft rerupture rate for the entire patient cohort was 3.6% (95% CI, 2.5%-5.1%), for patients with BTB grafts was 3.2% (95% CI, 1.9%-5.3%), and for patients with HT grafts was 4.4% (95% CI, 2.8%-6.8%).

CONCLUSION

Primary ACL reconstruction using BTB autografts demonstrated similar rates of RTS, return to previous activity levels, and reruptures compared with reconstruction using HT autografts.

Return to preinjury pivoting sports after anterior cruciate ligament reconstruction is different between males and females, as are the patient-reported reasons

PURPOSE

To investigate return to sport (RTS) after anterior cruciate ligament reconstruction (ACLR), differences based on sex and concomitant meniscal repair, and identify reasons why patients do not RTS.

METHODS

Overall, 232 patients undergoing ACLR, with or without concomitant meniscal repair, that were actively participating in pivoting sports at the time of injury, were prospectively recruited. At 2 years, return to preinjury pivoting sport was investigated and, if they had returned, whether they felt their performance was at (or better) or below preinjury status. Specific reasons for not returning were identified. RTS rates and reasons for not returning were compared based on sex and meniscal repair.

RESULTS

Overall, 140 patients (60.3%) had returned to their preinjury pivoting sport, of which 98 (70.0%) felt they were performing at (or beyond) preinjury status. While a significantly greater (p = 0.024) percentage of males (66.9%) versus females (52.4%) had returned to pivoting sports by 2 years, no differences (p = 0.708) were seen based on concomitant meniscal repair. Overall, 92 patients (39.7%) had not RTS, with primary reasons being loss of interest (21.7%), too busy due to their work and/or family environment (22.8%), or fear of reinjury or lacking confidence (17.4%). Other less-reported reasons included ongoing knee issues (6.5%) or not feeling physically ready (5.4%).

CONCLUSIONS

This study outlined specific reasons why community-level patients do not RTS, with RTS status (and reasons for not returning to preinjury pivoting sports) differing between males and females, with the latter returning at a significantly lower rate overall.

LEVEL OF EVIDENCE

Level IV.

Influence of Extra-Articular Augmentation on Clinical Outcomes and Survival in Patients Undergoing Anterior Cruciate Ligament Reconstruction: A Pseudorandomized Study

Background and Objectives: Up to 27% of anterior cruciate ligament (ACL) reconstruction cases result in a residual positive pivot shift sign, indicating anteroposterior and rotational instability. This instability can compromise returning to sports and increase the risk of further injuries. The biomechanical role of the anterolateral ligament (ALL) in controlling internal knee rotation is well known. However, there are no clinical trials comparing isolated ACL repairs to those combined with ALL reconstruction. Our objective is to compare the results of these techniques, with a primary focus on assessing knee stability and graft survival, to provide evidence for optimizing surgical approaches, particularly for athletes and physically active individuals. Materials and Methods: An observational study using paired score matching as a method of pseudo-randomization was conducted. Subjects were divided into an ACL group and an ACL+ALL group. Demographic and clinical variables were collected, as well as those related to complications and survival. Results: A total of 236 patients were included, which was reduced to 74 ACL and 37 ACL+ALL after pseudo-randomization, resulting in preoperatively comparable groups. During follow-up, differences in favor of ALL reinforcement were found on the pivot shift test (p = 0.007). No differences were found with regard to the Lachman test (p = 0.201), the International Knee Documentation Committee (IKDC) knee score (p = 0.169), the IKDC subjective score (p = 0.095), intensity of pain (p = 0.928), or complications (p = 0.529). Nor were differences found in the limb symmetry index; the single hop test (p = 0.710); the triple hop test (p = 0.653); the crossover hop test (p = 0.682); the 6 meter timed hop test (p = 0.360); the normalized Y-balance test (YBT) (p = 0.459 anterior; p = 0.898 posterolateral; and p = 0.211 posteromedial directions); or the limb symmetry index of the composite YBT (p = 0.488). There were no differences either with respect to return to sports practice (p = 0.723) or survival (p = 0.798). Conclusions: Patients treated by means of the ACL+ALL technique obtained higher rotational stability, as measured by the pivot shift test, than those subjected to an isolated ACL repair. No differences were found with respect to Lachman test, complications, IKDC, pain, or survival.

Sport-specific differences in ACL injury, treatment and return to sports: Basketball

Basketball is an intense, fast-paced game that is physically, highly demanding. Certain aspects of the game, such as the quick pivoting and cutting movements, predispose the players to serious knee injuries, including anterior cruciate ligament (ACL) tears. While an ACL tear can be a devastating condition for players, multidisciplinary management of the injury can provide the players with a reasonable chance to return to play at the pre-injury level. This article aims to review the general principles and guidelines for the management of ACL injury in basketball players. The diagnosis, surgical treatment, rehabilitation and return to sports are discussed from European and North American perspectives. With a comprehensive and multidisciplinary approach to this condition, medical professionals can provide injured basketball players with a favourable prognosis for returning to play at the pre-injury level. To return to normal life and basketball after ACL reconstruction, the proposed approach includes (1) the selection of the appropriate surgical graft and technique, (2) maintaining a healthy and persistent mental state during rehabilitation, and (3) following a scientific rehabilitation programme based on personalized recovery. LEVEL OF EVIDENCE: Level V.

Progressive resistance training improves single-leg vertical jump after anterior cruciate ligament reconstruction: Non-randomized controlled trial study

OBJECTIVES

The study was investigating the effect of a progressive resistance training program on the recovery of patients with anterior cruciate ligament reconstruction in terms of kinematics, kinetics and muscle strength.

DESIGN

Longitudinal cohort study.

SETTING

Hospital laboratory.

PARTICIPANTS

Of the 42 patients were finally included: 22 patients in the progressive resistance training group and 20 in the control group.

MAIN OUTCOME MEASURES

Questionnaire, single-leg vertical jump, and muscle strength were collected preoperatively and at 16, 28 weeks, and 1 year postoperatively.

RESULTS

At 28 weeks, the height of the single-leg vertical jump for the injured knee was 203 and 157 mm (p = 0.045) and the peak knee flexion angle after landing for the injured knee was 31°and 23° (p = 0.027) in the progressive resistance training and control groups, respectively. The progressive resistance training group showed a significant increase in the knee extensor symmetry index after the 24-week exercise training compared from 58% preoperatively to 79% (p = 0.001) after training completion, which lasted up to 1 year postoperatively.

CONCLUSION

Progressive resistance training significantly improved knee extensor symmetry, single-leg vertical jump height, and peak knee flexion angle after landing, outperforming the control group across all measures.

The effects of social determinants of health on anterior cruciate ligament injury recovery

Context

Over 200,000 anterior cruciate ligament (ACL) injuries occur in the United States each year. While many patients choose to pursue ACL reconstruction (ACLR), the impact of social determinants of health (SDOH) on outcomes is unclear.

Objective

The purpose of this study was to review and synthesize current literature to determine the impact of SDOH on outcomes following ACL reconstruction.

Data sources

A systematic search of PubMed, CINAHL, Medline, PsychINFO, and Scopus was completed.

Study selection

Articles reporting outcomes following ACLR were included if they discussed at least one SDOH and provided ACLR failure rates.

Study design

Systematic review.

Level of evidence

Level I.

Results

After screening 712 studies, 13 were found that met inclusion criteria and were analyzed. Studies commonly examined the correlations between race, income, location, education, and insurance on outcomes following ACLR. Three studies found that the ACL revision risk for Black patients compared to White patients ranged from 0.23 to 0.78, while the revision risk for Hispanic patients compared to White patients ranged from 0.7 to 0.83. One study reported finding that the odds ratio of revision for the White patients was 1.32. Another study reported no difference in revision risk based on race. Patients living in urban areas were found to have improved outcomes compared to rural areas (Mean IKDC (Urban 85.3 vs Rural 81.87) and Tegner-Lysholm (Urban 88.26 vs Rural 84.82)). Lower socioeconomic status was correlated with decreased post-operative functional scores (KOOS, Marx and IKDC).

Conclusion

Several SDOH such as White race, rural location, and low socioeconomic status may be independently correlated with worse ACLR outcomes in the form of increased revision rates or worse post-operative functional scores. However, further research is needed to better elucidate the degree of impact and interconnectedness of SDOH domains on ACLR patient outcomes.

The Minimum Patient Acceptable Symptom State for the ACL-Return to Sport after Injury Scale Among Patients Treated With Anterior Cruciate Ligament Reconstruction

BACKGROUND

Despite most patients reporting optimal knee function after anterior cruciate ligament reconstruction (ACLR), not all return to their pre-injury level of sport, often due to psychological factors. The ACL-Return to Sport after Injury Scale (ACL-RSI) was developed to measure the emotions, confidence in performance, and risk appraisal among athletes returning to sport. The purpose of this study was to determine the Patient Acceptable Symptom State (PASS) threshold for the ACL-RSI in patients undergoing ACLR.

MATERIALS AND METHODS

Patients with an ACL injury that required surgical reconstruction were included in this prospective study. All patients underwent ACLR with a bone-patellar tendon-bone autograft and completed the ACL-RSI 12 months postoperatively. An anchor-based approach was used to generate a receiver operating characteristic curve and establish the PASS threshold. Multivariable regression analyses were used to evaluate the effect of age, sex, and baseline score on likelihood of achieving PASS.

RESULTS

A total of 113 patients (37% female) with a mean age of 28.1±8.2 years and a mean body mass index of 24.7±3.5 kg/m2 were included. At 12 months postoperatively, the threshold value for the PASS of the ACL-RSI was 40 (robust area under the curve: 0.89; sensitivity: 81%; specificity: 85%). Baseline score, sex, and age had no significant influence on achieving PASS at 12 months postoperatively.

CONCLUSION

In a group of patients undergoing ACLR with bone-patellar tendon-bone autograft, the PASS threshold value was 40 for the ACL-RSI at 12 months postoperatively. The PASS value for the ACL-RSI established from this study can be useful for designing future clinical trials. [Orthopedics. 2025;48(1):20-24.].

Hop to It! A Systematic Review and Longitudinal Meta-analysis of Hop Performance After ACL Reconstruction

BACKGROUND

Hop testing is widely used by clinicians to monitor rehabilitation and decide when to return to sport following anterior cruciate ligament reconstruction (ACLR); however, the trajectory of long-term hop performance has not been summarised.

OBJECTIVE

To investigate hop performance change over time after ACLR.

DESIGN

Systematic review with longitudinal meta-analysis.

DATA SOURCES

MEDLINE, EMBASE, CINAHL, Scopus, Cochrane CENTRAL and SPORTDiscus to 28 February 2023.

ELIGIBILITY CRITERIA

Studies with ≥ 50 participants following primary ACLR, with mean participant age of 18-40 years, reporting a quantitative measure of hop performance (e.g. single forward hop distance). Results had to be reported for the ACLR limb and compared with (1) the contralateral limb (within person) and/or (2) an uninjured control limb (between person).

RESULTS

We included 136 studies of 23,360 participants. Performance was similar across different hop tests, with steep initial improvements in within-person symmetry, tailing off after 18-24 months. ACLR limb hop performance was 5-10% lower compared with the contralateral limb at 1 year post-surgery, with largest deficits observed for vertical hop [87.0% contralateral limb (95% CI 85.3-88.8) compared with single forward hop 93.8% (95% CI 92.8-94.9)]. By 3-5 years, results were similar between ACLR and contralateral limbs. There were limited data for between-person comparisons (n = 17 studies). Exploratory analyses showed deficits in all forward hopping tests to be very strongly correlated with each other [e.g. single forward and triple hop rho = 0.96 (95% CI 0.90-0.99)], though there was discordance in the relationship between single forward hop and vertical hop performance [rho = 0.27 (95% CI - 0.53 to 0.79)].

CONCLUSIONS

Hop performance is comparable to the uninjured limb by 3-5 years post-ACLR, with the greatest deficits in within-person symmetry present in vertical and side hop tests. Assessment of hopping in multiple planes and comparison with uninjured controls, may provide the most complete evaluation of functional performance.

Single Nucleotide Polymorphisms and Tendon/Ligament Injuries in Athletes: A Systematic Review and Meta-analysis

This systematic review and meta-analysis aimed to identify the association between genetic polymorphisms and tendon and ligament injuries in adolescent and adult athletes of multiple competition sports. The PubMed, Web of Science, EBSCO, Cochrane Library, and MEDLINE databases were searched until July 7, 2023. Eligible articles included genetic studies on tendon and ligament injuries and comparisons between injured and non-injured athletes. This review included 31 articles, comprising 1,687 injury cases and 2,227 controls, from a meta-analysis of 12 articles. We identified 144 candidate gene polymorphisms (only single nucleotide polymorphisms were identified). The meta-analyses included vascular endothelial growth factor A (VEGFA) rs699947, collagen type I alpha 1 rs1800012, collagen type V alpha 1 rs12722, and matrix metalloproteinase 3 rs679620. The VEGFA rs699947 polymorphism showed a lower risk of injuries in athletes with the C allele ([C vs. A]: OR=0.80, 95% CI: 0.65-0.98, I 2 =3.82%, p=0.03). The risk of these injuries were not affected by other polymorphisms. In conclusion, the VEGFA rs699947 polymorphism is associated with the risk of tendon and ligament injuries in athletes. This study provides insights into genetic variations that contribute to our understanding of the risk factors for such injuries in athletes.

Association Between Autograft Choice and Psychological Readiness to Return to Sport After ACL Reconstruction

Background

It has been demonstrated that an athlete's psychological readiness contributes to one's ability to successfully return to sport (RTS) after anterior cruciate ligament (ACL) reconstruction. However, the effect of graft choice on psychological readiness is not yet understood.

Purpose/Hypothesis

The purpose of this study was to evaluate the association between graft choice and an athlete's psychological readiness to RTS. It was hypothesized that similar ACL-Return to Sport after Injury (ACL-RSI) scores would be achieved among patients who underwent ACL reconstruction with quadriceps autograft (QA), hamstring tendon autograft (HA), and bone-patellar tendon-bone (BTB) autograft.

Study Design

Cohort study; Level of evidence, 3.

Methods

Patients who underwent primary ACL reconstruction at a single institution between January 2017 and December 2018 were placed into separate cohorts depending on graft type (HA, BTB, or QA; n = 30 patients in each group), and the ACL-RSI, International Knee Documentation Committee subjective form, and Lysholm scores were compared between the different graft cohorts at 6 months postoperatively, at RTS, and at 2 years postoperatively. Also, the rate of patients who achieved an ACL-RSI score of ≥65 (predictive of return to preinjury sport at 2 years postoperatively) was calculated, as was the RTS rate and time.

Results

The QA group demonstrated significantly higher ACL-RSI scores than both the HA and BTB groups at 6 months postoperatively (P < .0001) and RTS (P = .011). The QA group also had a higher rate of achieving ≥65 on ACL-RSI than the other groups at 6 months postoperatively (P = .002) and RTS (P = .024). There was no significant difference in the RTS rate between the 3 groups, although the QA group demonstrated a significantly quicker return (QA, 8.1 months; BTB, 9.6 months; HA, 10.5 months; P < .001).

Conclusion

Athletes undergoing primary ACL reconstruction with QA achieved a higher mean ACL-RSI score and more often achieved a score of ≥65 at the 6-month and RTS time points compared with the HA and BTB groups. QA may afford an advantage over other grafts in terms of improved psychological readiness to RTS.

Effects of Neuromuscular Electrical Stimulation on Quadriceps Femoris Muscle Strength and Knee Joint Function in Patients After ACL Surgery: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Background

Quadriceps weakness is a common barrier to effective rehabilitation after anterior cruciate ligament (ACL) surgery. Neuromuscular electrical stimulation (NMES)-the application of electrical currents to induce muscle contraction-has been used as part of the postoperative rehabilitation regimen.

Purpose

To investigate the effects of NMES on the recovery of quadriceps strength and knee function after ACL surgery.

Study Design

Systematic review; Level of evidence, 1.

Methods

A search was conducted in the Web of Science, Embase, Cochrane Library, and PubMed databases between inception and August 2023 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Included were randomized controlled trials of patients undergoing NMES as postoperative rehabilitation after ACL reconstruction or repair, with standard physical therapy as the control intervention. The quality of the included studies was assessed according to the Cochrane Collaboration risk-of-bias tool. Lower limb function was assessed qualitatively, and standardized mean differences (SMDs) in muscle strength and Lysholm scores were analyzed quantitatively and pooled using a random-effects model.

Results

Eleven studies (N = 202 patients) met our inclusion criteria. The meta-analysis of muscle strength values, which included 9 studies, showed that patients who underwent physical rehabilitation with adjunctive NMES had better recovery and improvement in quadriceps muscle strength compared with standard physical therapy at both short- and long-term follow-ups (≤6 weeks: SMD, 0.53 [95% CI, 0.27-0.79] vs >6 weeks: SMD, 0.59 [95% CI, 0.18-0.99]; p < 0.001). Moreover, subgroup analyses showed that earlier physical rehabilitation with the assistance of NMES resulted in better muscle strength recovery (≤1 week: SMD, 1.48 [95% CI, 0.80-2.17] vs >1 week: SMD, 0.44 [95% CI, 0.21-0.67]; p < 0.001). The meta-analysis of Lysholm scores, which included 3 studies, did not indicate any significant differences between the assisted NMES and control groups.

Conclusion

Our study demonstrated that in both short- and long-term follow-up studies, postoperative rehabilitation with NMES after ACL surgery significantly increased quadriceps muscle strength compared with standard rehabilitation alone.

Sex-based differences in physical and psychological recovery, and return to sport, following anterior cruciate ligament reconstruction

BACKGROUND

A robust comparison of the recovery pathway between sexes after anterior cruciate ligament reconstruction (ACLR) is lacking. This study investigated sex-based differences in physical and psychological recovery, and return to sport (RTS), after ACLR.

METHODS

104 community-level patients underwent ACLR. Patients were evaluated at 6-, 12- and 24-months with the Anterior Cruciate Ligament Return to Sport after Injury Scale (ACL-RSI), International Knee Documentation Committee (IKDC) form and Tegner Activity Scale (TAS), a 4-hop test battery including the 6-meter timed hop (6MTH) and the single (SHD), triple (THD) and triple crossover (TCHD) hop tests for distance, and peak isokinetic knee extensor and flexor torque. Sex-based differences were assessed, while regression analysis modelled the relationship between patient characteristics and outcomes, with 24-month psychological readiness to RTS.

RESULTS

All PROMS improved (p < 0.05), with males reporting higher 24-month ACL-RSI (p = 0.002), IKDC (p = 0.007) and TAS (p = 0.005) scores. A greater percentage of males returned to pivoting sports at 24 months (p = 0.030, males 60.0%, females 40.8%). Males demonstrated higher knee extensor strength LSIs at 6 (p = 0.037) and 24 (p = 0.047) months, and higher knee flexor strength LSIs at 6 (p = 0.007) and 12 (p = 0.002) months. IKDC knee scores (β = 24.9; 95% CI, 10.8 to 35.0), male sex (β = 12.2; 95% CI, 3.9 to 20.4) and the 6MTH LSI (β = 1.31; 95% CI, 0.6 to 2.1) were associated with the ACL-RSI.

CONCLUSIONS

In community-level ACLR patients, females demonstrated lower physical performance recovery, subjective function and psychological readiness, as well as a lower rate of RTS.