Anterior Cruciate Ligament Injuries in Children and Adolescents

Application of Machine Learning Methods to Investigate Joint Load in Agility on the Football Field: Creating the Model, Part I

Laboratory studies have limitations in screening for anterior cruciate ligament (ACL) injury risk due to their lack of ecological validity. Machine learning (ML) methods coupled with wearable sensors are state-of-art approaches for joint load estimation outside the laboratory in athletic tasks. The aim of this study was to investigate ML approaches in predicting knee joint loading during sport-specific agility tasks. We explored the possibility of predicting high and low knee abduction moments (KAMs) from kinematic data collected in a laboratory setting through wearable sensors and of predicting the actual KAM from kinematics. Xsens MVN Analyze and Vicon motion analysis, together with Bertec force plates, were used. Talented female football (soccer) players (n = 32, age 14.8 ± 1.0 y, height 167.9 ± 5.1 cm, mass 57.5 ± 8.0 kg) performed unanticipated sidestep cutting movements (number of trials analyzed = 1105). According to the findings of this technical note, classification models that aim to identify the players exhibiting high or low KAM are preferable to the ones that aim to predict the actual peak KAM magnitude. The possibility of classifying high versus low KAMs during agility with good approximation (AUC 0.81-0.85) represents a step towards testing in an ecologically valid environment.

Use of cryotherapy in the postoperative management of paediatric anterior cruciate ligament reconstruction: a prospective randomised controlled trial

To investigate the efficacy of cryotherapy in relieving postoperative pain and restoring knee range-of-motion (ROM) after paediatric anterior cruciate ligament reconstruction (ACLR). Patients undergoing primary ACLR were randomised into cryotherapy or non-cryotherapy groups. Those receiving cryotherapy were subjected to a standardised icing protocol. Icing schedules were used to assess compliance. Standard postoperative rehabilitation protocol was followed for both groups. Outcome measurements were visual analogue scale at rest and movement and knee ROM. Patients were assessed on postoperative day 1 (POD1), 1, 4 and 6 weeks. Twenty-one out of 42 patients received cryotherapy. Both groups were similar in demographics, surgical technique and use of intraoperative anaesthesia. Patients in the cryotherapy group reported lower overall mean pain scores throughout the study duration at rest (0.61 ± 1.70, 95% CI = 0.23-0.99 vs. 1.06 ± 2.03, 95% CI = 0.60-1.53) and on movement (2.19 ± 2.68, 95% CI = 1.59-2.79 vs. 3.13 ± 2.75, 95% CI = 2.51-3.75; P  = 0.032). Knee flexion in the cryotherapy group showed better recovery of knee flexion from week 4 onwards. Improvement of knee flexion from POD1 is statistically significant at week 6 (98.7 ± 19.1°, 95% CI = 89.5-107.9 vs. 65.4 ± 49.9°, 95% CI = 42.7-88.1; P  = 0.010) and overall mean (71.2 ± 35.9°, 95% CI = 61.2-81.1 vs. 45.3 ± 55.5°, 95% CI = 30.4-60.2; P  = 0.005). The cryotherapy group reported statistically significant better degree of overall mean knee extension (1.2 ± 3.3°, 95% CI = 0.5-2.0 vs. 2.6 ± 4.6°, 95% CI = 1.6-3.7; P  = 0.032). The use of cryotherapy in postoperative ACLR recovery in paediatrics is a simple yet effective measure resulting in short-term pain relief and improvement in knee flexion.

Regenerative Anterior Cruciate Ligament Healing in Youth and Adolescent Athletes: The Emerging Age of Recovery Science

Anterior cruciate ligament (ACL) injuries mainly arise from non-contact mechanisms during sport performance, with most injuries occurring among youth or adolescent-age athletes, particularly females. The growing popularity of elite-level sport training has increased the total volume, intensity and frequency of exercise and competition loading to levels that may exceed natural healing capacity. Growing evidence suggests that the prevailing mechanism that leads to non-contact ACL injury from sudden mechanical fatigue failure may be accumulated microtrauma. Given the consequences of primary ACL injury on the future health and quality of life of youth and adolescent athletes, the objective of this review is to identify key "recovery science" factors that can help prevent these injuries. Recovery science is any aspect of sports training (type, volume, intensity, frequency), nutrition, and sleep/rest or other therapeutic modalities that may prevent the accumulated microtrauma that precedes non-contact ACL injury from sudden mechanical fatigue failure. This review discusses ACL injury epidemiology, current surgical efficacy, the native ACL vascular network, regional ACL histological complexities such as the entheses and crimp patterns, extracellular matrix remodeling, the concept of causal histogenesis, exercise dosage and ligament metabolism, central nervous system reorganization post-ACL rupture, homeostasis regulation, nutrition, sleep and the autonomic nervous system. Based on this information, now may be a good time to re-think primary ACL injury prevention strategies with greater use of modified sport training, improved active recovery that includes well-planned nutrition, and healthy sleep patterns. The scientific rationale behind the efficacy of regenerative orthobiologics and concomitant therapies for primary ACL injury prevention in youth and adolescent athletes are also discussed.

Initial Assessment and Management of Select Musculoskeletal Injuries: A Team Physician Consensus Statement

ABSTRACT

Musculoskeletal injuries occur frequently in sport during practice, training, and competition. Injury assessment and management are common responsibilities for the team physician. Initial Assessment and Management of Musculoskeletal Injury-A Team Physician Consensus Statement is title 23 in a series of annual consensus documents written for the practicing team physician. This statement was developed by the Team Physician Consensus Conference, an annual project-based alliance of six major professional associations. The goal of this document is to help the team physician improve the care and treatment of the athlete by understanding the initial assessment and management of selected musculoskeletal injuries.

Initial Assessment and Management of Select Musculoskeletal Injuries: A Team Physician Consensus Statement

ABSTRACT

Musculoskeletal injuries occur frequently in sport during practice, training, and competition. Injury assessment and management are common responsibilities for the team physician. Initial Assessment and Management of Musculoskeletal Injury-A Team Physician Consensus Statement is title 23 in a series of annual consensus documents written for the practicing team physician. This statement was developed by the Team Physician Consensus Conference, an annual project-based alliance of six major professional associations. The goal of this document is to help the team physician improve the care and treatment of the athlete by understanding the initial assessment and management of selected musculoskeletal injuries.

Greater self-efficacy, psychological readiness and return to sport amongst paediatric patients compared with adolescents and young adults, 8 and 12 months after ACL reconstruction

PURPOSE

The purpose of this study was to evaluate differences in rehabilitation-specific outcomes between paediatric patients, adolescents and young adults within the first 2 years after anterior cruciate ligament (ACL) reconstruction. A further aim was to determine whether patient age was associated with an increased risk of not achieving symmetrical muscle function within the first 2 years after ACL reconstruction.

METHODS

The patient data in the present study were extracted from the rehabilitation outcome registry, Project ACL. Patients aged 11-25 years registered for primary ACL reconstruction with a hamstring tendon autograft between April 1, 2013 and November 23, 2020 were included. A total of 691 patients met the inclusion criteria and were included in the study; 41 paediatric patients (females 11-13, males 11-15 years), 347 adolescents (females 14-19, males 16-19 years) and 303 young adults (females 20-25, males 20-25 years).

RESULTS

The comparison between groups revealed that 70% of paediatric patients, 39% of adolescents and 35% of young adults had returned to knee-strenuous sport at 8 months and that 90% of paediatric patients, 71% of adolescents and 62% of young adults had returned to sport at 12 months. Paediatric patients also reported higher scores compared with both the other patient groups on the Knee Self-Efficacy Scale (K-SES) and the Anterior Cruciate Ligament Return to Sport after Injury scale (ACL-RSI) at 8 and 12 months.

CONCLUSIONS

A larger proportion of paediatric patients had returned to sport compared with adolescents and young adults 8 and 12 months after ACL reconstruction. Paediatric patients also reported higher self-efficacy and greater psychological readiness to return to sport at 8 and 12 months than the other two groups. No differences in terms of muscle function tests when comparing paediatric patients, adolescents and young adults were found.

LEVEL OF EVIDENCE

II.

Anterior cruciate ligament injuries in female athletes

The anterior cruciate ligament (ACL) is frequently injured in elite athletes, with females up to eight times more likely to suffer an ACL tear than males. Biomechanical and hormonal factors have been thoroughly investigated; however, there remain unknown factors that need investigation. The mechanism of injury differs between males and females, and anatomical differences contribute significantly to the increased risk in females. Hormonal factors, both endogenous and exogenous, play a role in ACL laxity and may modify the risk of injury. However, data are still limited, and research involving oral contraceptives is potentially associated with methodological and ethical problems. Such characteristics can also influence the outcome after ACL reconstruction, with higher failure rates in females linked to a smaller diameter of the graft, especially in athletes aged < 21 years. The addition of a lateral extra-articular tenodesis can improve the outcomes after ACL reconstruction and reduce the risk of failure, and it should be routinely considered in young elite athletes. Sex-specific environmental differences can also contribute to the increased risk of injury, with more limited access to and availablility of advanced training facilities for female athletes. In addition, football kits are designed for male players, and increased attention should be focused on improving the quality of pitches, as female leagues usually play the day after male leagues. The kit, including boots, the length of studs, and the footballs themselves, should be tailored to the needs and body shapes of female athletes. Specific physiotherapy programmes and training protocols have yielded remarkable results in reducing the risk of injury, and these should be extended to school-age athletes. Finally, psychological factors should not be overlooked, with females' greater fear of re-injury and lack of confidence in their knee compromising their return to sport after ACL injury. Both intrinsic and extrinsic factors should be recognized and addressed to optimize the training programmes which are designed to prevent injury, and improve our understanding of these injuries.

Clinical outcomes of different autografts used for all-epiphyseal, partial epiphyseal or transphyseal anterior cruciate ligament reconstruction in skeletally immature patients - a systematic review

BACKGROUND

Different types of grafts can be used for anterior cruciate ligament reconstruction (ACLR). There is little published data regarding skeletally immature patients. The purpose of this systematic review was to assess the clinical outcomes and complications for different autograft types used in all-epiphyseal, transphyseal and partial epiphyseal/hybrid ACLR in skeletally immature children and adolescents.

METHODS

PubMed, Embase and Cochrane databases were systematically searched for literature regarding ACLR using hamstrings, quadriceps or bone-patellar-tendon-bone (BPTB) autografts in skeletally immature patients. Studies were included if they examined at least one of the following outcomes: graft failure, return to sport(s), growth disturbance, arthrofibrosis or patient reported outcomes and had a minimum follow-up of 1 year. Case reports, conference abstracts and studies examining allografts and extra-articular or over-the-top ACL reconstruction techniques were excluded. Graft failure rates were pooled for each graft type using the quality effects model of MetaXL. A qualitative synthesis of secondary outcomes was performed.

RESULTS

The database search identified 242 studies. In total 31 studies were included in this review, comprising of 1358 patients. Most patients (81%) were treated using hamstring autograft. The most common used surgical technique was transphyseal. The weighted, pooled failure rate for each graft type was 12% for hamstring tendon autografts, 8% for quadriceps tendon autografts and 6% for BPTB autografts. Confidence intervals were overlapping. The variability in time to graft failure was high. The qualitative analysis of the secondary outcomes showed similar results with good clinical outcomes and low complication rates across all graft types.

CONCLUSIONS

Based on this review it is not possible to determine a superior graft type for ACLR in skeletally immature. Of the included studies, the most common graft type used was the hamstring tendon. Overall, graft failure rates are low, and most studies show good clinical outcomes with high return to sports rates.

Imaging the pediatric anterior cruciate ligament: not little adults

An increased incidence of anterior cruciate ligament (ACL) injuries in children over the last few decades has led to a corresponding increase in ACL reconstruction procedures in children. In this review, we will illustrate unique features seen when imaging the ACL in children versus adults. After briefly reviewing relevant normal ACL anatomy, we will review imaging findings of congenital ACL dysplasia. This is followed by a discussion of imaging ACL avulsions. Lastly, we will review the different types of ACL reconstruction procedures performed in skeletally immature children and their post-operative appearances.

Knee valgus and patellofemoral instability after pediatric anterior cruciate ligament reconstruction: a case report and review of the literature

BACKGROUND

Pediatric athletes who undergo anterior cruciate ligament reconstruction are at risk for a growth deformity if the surgery violates the physes.

CASE

A 12-year-old African American boy underwent anterior cruciate ligament reconstruction using a hamstring autograft. The procedure violated the distal femoral growth plate and the perichondrial ring of LaCroix, resulting in a distal femoral lateral physeal growth arrest. Three years later, he had developed a 15° valgus deformity, an increased quadriceps angle and patellofemoral instability. He was able to return to sports after undergoing a distal femoral osteotomy to correct the valgus and medial patellofemoral ligament reconstruction to stabilize the patella.

CONCLUSION

Anterior cruciate ligament reconstruction in athletes with open physes has the potential to cause distal femoral valgus deformity, an increased quadriceps angle, and subsequent patellofemoral instability.

Skeletally Immature Patients With Classic Anterior Cruciate Ligament Bone Bruise Patterns Have a Higher Likelihood of Having an Intact Anterior Cruciate Ligament Compared With Skeletally Mature Patients

BACKGROUND

The incidence of anterior cruciate ligament (ACL) tears in skeletally immature patients with an ACL bone contusion pattern has been sparsely investigated. The purpose of this study is to investigate whether physeal status has an influence on the likelihood of sustaining an ACL tear when classic bipolar ACL bone bruising pattern is present.

METHODS

Magnetic resonance imaging reports were queried for "contusion" on all patients between 6 and 22 years between 2015 and 2019. Images were reviewed to denote all intra-articular pathology and the physeal status of the femur and tibia. The primary outcome was the incidence of ACL tears in patients with the presence of bipolar bone contusions. Fischer exact testing was used to determine associations.

RESULTS

Of 499 patients included, 269 of those had bipolar bone contusions. Patients with bipolar bone contusions and ACL tears had a shorter duration between injury and imaging date compared with patients with ACL tears without bipolar bone contusions (6.9 vs. 38.6 d, P =0.05). Patients with an open femoral physis had a higher likelihood of having an intact ACL despite the presence of bipolar bone contusions than patients with a closed femoral physis (10.8% vs. 1.0%, P <0.001). Of patients with bipolar bone contusions, those with an intact ACL were younger than patients with an ACL tear (14.6 vs. 16.4, P =0.017).

CONCLUSIONS

Although bipolar bone contusions of the central lateral femoral condyle and posterior lateral tibial plateau are typically found after ACL injury, these bipolar contusions can be found concomitantly with an intact ACL and were more often found in relatively younger patients. Patients who have an open femoral physis have a higher likelihood to have an intact ACL despite the presence of bipolar bone contusions compared with patients who have a closed femoral physis.

LEVEL OF EVIDENCE

Level IV-cross-sectional.

Increasing incidence of anterior cruciate ligament reconstruction: a 17-year population-based study

PURPOSE

Anterior cruciate ligament (ACL) injuries are one of the most frequently studied injuries in orthopedic care and research. However, limited epidemiological data are available in Canada regarding trend and distribution of anterior cruciate ligament reconstruction (ACLR). In this paper, our purpose was to assess trends of ACLR between 2002/03 and 2018/19 by age, sex, season of surgery, and location (inpatient vs outpatient) of surgery.

METHODS

In this descriptive epidemiological study of retrospective data available from Alberta Ministry of Health, we report annual incidence of ACLR between 2002/03 until 2018/19 among Albertans aged 10 years and older. Information was collected by authors from physician claims database for primary ACLR and revision ACLR and linked with other databases. Incidence proportions (number of ACLR/100,000 population) were calculated and compared by age category and gender over the study period.

RESULTS

A total of 28,401 primary ACLR and 2085 revision ACLR were identified during the study period. Age-standardized annual incidence of primary ACLR increased from 40.6 to 51.2 per 100,000 population aged 10 years and older. Average annual increase in ACLR incidence was higher among females (1.8% per years) compared to males (0.96% per year). The overall peak incidence and peak incidence among males was observed in 20-29 year age group, whereas peak incidence in females was observed in 10-19 years of age. The number of ACLR in females outnumbers those among males for 10-19 year age group. Generally, a lower proportion of ACLR were conducted in summer compared to other seasons. Primary ACLR conducted in outpatient setting increased from 72% in 2002/03 to 97% in 2018/19.

CONCLUSION

The incidence of ACLR is increasing in Alberta, especially among females and among younger cohorts under 20 years of age. This information can help clinicians to provide patient education and policy-makers to design and implement targeted ACL injury prevention programs.

LEVEL OF EVIDENCE

Level III.

Age, female sex, and oral contraceptive use are risk factors for anterior cruciate ligament reconstruction: A nationwide database study

BACKGROUND

The purpose of this study was to investigate risk factors affecting anterior cruciate ligament (ACL) tears and outcomes following ACL reconstruction in males versus females. This study also analyzed oral contraceptive pill (OCP) use, demographics (e.g., body mass index [BMI], age group), comorbidities (e.g., diabetes, hypertension), and post-operative systemic complications (e.g., anemia, malignant hyperthermia) in patients undergoing ACL reconstruction.

METHODS

Medical records of patients undergoing ACL reconstruction from 2010-2018 were queried from the PearlDiver administrative claims database current procedural terminology (CPT) and international classification of disease (ICD) codes. The following information was collected using ICD-9/ICD-10 codes: concurrent use of OCPs, concomitant meniscus repair, demographics, age, comorbidities, and systemic complications. The number of ACL reconstructions in females and males were analyzed using multivariate regressions.

RESULTS

Of 11,498 ACL reconstructions, 5,967 (51.9%) were in females and 5,531 (48.1%) were in males. The majority of patients were ages 15-19 (24.1%) and were not obese (BMI < 30 kg/m²) (35.9%). A greater proportion of female patients undergoing ACL reconstruction were between 15-19 years old (P < 0.001) and obese (BMI > 40 kg/m²) (P < 0.001). A larger proportion of females aged 15-39 taking OCPs underwent ACL reconstruction compared to those not taking OCPs within the same age group (P < 0.001).

CONCLUSION

ACL tears are more common in female patients compared to males and are more commonly treated with ACL reconstruction. This study identified several factors that may be associated with the increased risk of ACL tears in females, including young age (age 15-39), obesity (BMI > 40 kg/m²), and the use of OCPs prior to ACL reconstruction, which warrant further investigation and attention from surgeons.

The Spectrum of Anterior Cruciate Ligament Reconstruction Options for the Pediatric and Adolescent Patient: A Narrative Review

As youth sports participation has increased in recent years, injuries to the anterior cruciate ligament (ACL) have become increasingly common in pediatric patients. Historically, ACL reconstruction was delayed in pediatric patients to avoid physeal damage with the potential for leg-length discrepancy or angular deformity. Current research shows that delaying reconstruction or choosing nonoperative management is associated with increased rates of meniscal and chondral injuries, persistent knee instability, and low rates of return to previous activity. Early ACL reconstruction using techniques to avoid physeal growth disturbance is now widely accepted among physicians. The purpose of this review was to describe the pediatric ACL in terms of the relevant anatomy and biomechanics, physical examination, and diagnostic imaging. In addition, the importance of skeletal age and possible physeal injury is discussed in the context of ACL reconstruction options by skeletal age and remaining growth potential.

Risk of reoperation after primary anterior cruciate ligament reconstruction in children and adolescents

OBJECTIVE

To examine the incidence and risk factors of any-cause reoperation after primary ACLR in children and adolescents.

DESIGN

Retrospective Cohort.

SETTING

Electronic medical records from a large tertiary care, single institution integrated healthcare delivery system.

PATIENTS

Patients were under the age of 18 years and had anterior cruciate ligament reconstruction. They were excluded if they had a multi-ligamentous knee injury or <1 year follow-up.

INTERVENTIONS

Patients were further identified to have undergone a subsequent knee operation ipsilaterally or contralateral ACLR.

MAIN OUTCOME MEASURES

The rate of any-cause reoperation was our primary outcome measure.

RESULTS

The median age was 16. There were 208 females (53.9%) and 178 males (46.1%) included. The median follow-up was 25 months with a minimum of 12 months (interquartile range: 16.0, 46.0). The rate of any-cause reoperation was 34.7%. There was no statistically significant difference between those who underwent reoperation versus those who did not undergo reoperation relative to age, sex, BMI, graft type, or the presence of concomitant meniscal injury. The rates of ipsilateral ACLR and contralateral ACLR at any time during the study period was 8.0% and 10.9% respectively. There was no statistically significant difference for rate of reoperation between graft types, between various concomitant injuries, between those who underwent meniscus repair or no repair.

CONCLUSIONS

This study reflects a 34.7% rate of a subsequent knee operation after ACLR in patients younger than 18 years. These findings can be used to inform pediatric patients undergoing primary ACLR on their risk of returning to the operating room.

Lower rate of acceptable knee function in adolescents compared with young adults five years after acl reconstruction: results from the swedish national knee ligament register

Background

The number of studies with a large cohort of patients that primarily focus on patient-reported outcomes after ACL reconstruction in children and adolescents is limited. The purpose of the present study was to determine whether patient age affects the proportion of patients that achieve a patient-acceptable symptom state (PASS) on the Knee injury and Osteoarthritis Outcome Score (KOOS) subscales one, two, five and 10 years after an ACL reconstruction.

Methods

The patient data in the present study were extracted from the Swedish National Knee Ligament Register (SNKLR). Patients aged between five and 35 years that underwent a primary ACL reconstruction between 1 January 2005 and 31 December 2017 and had completed the KOOS questionnaire at the one-, two-, five- or 10-year follow-up were included. A total of 2,848 patients met the inclusion criteria and were included in the study; 47 paediatric patients (females 5–13, males 5–15 years), 522 adolescents (females 14–19, males 16–19 years) and 2,279 young adults (females 20–35, males 20–35 years). The results from the KOOS were presented as the mean and 95% confidence interval (CI) for the mean. For comparisons between groups, the chi-square test was used for non-ordered categorical variables. For pairwise comparisons between groups, Fisher’s exact test (2-sided) was used for dichotomous variables. All the statistical analyses was set at 5%.

Results

Adolescents reported a significantly lower score than young adults on the KOOS4 at the two- (68.4 vs. 72.1; P < 0.05), five- (69.8 vs. 76.0; P < 0.05) and 10-year follow-ups (69.8 vs. 78.2; P < 0.05). Moreover, a significantly smaller proportion of adolescents achieved a PASS on each of the KOOS subscales when compared with young adults at the five-year follow-up (Symptoms: 83.3% vs. 91.6%; Pain: 42.9% vs. 55.3%; Function in daily living: 31.4% vs. 41.1%; Function in sports and recreational activities: 42.3% vs. 55.7%; Knee-related quality of life: 50.0% vs. 65.0%; P < 0.05).

Conclusions

A significantly smaller proportion of adolescents achieved a PASS on each of the KOOS subscales when compared with young adults five years after ACL reconstruction. The results of the present study provide important information for physicians and physiotherapists treating young patients after an ACL injury and they can aid in providing realistic expectations in terms of the mid- and long-term outcomes.

Level of evidence

Prospective Observational Register/Cohort Study, Level II.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05727-6.

17-Year Results following Transepiphyseal Anterior Cruciate Ligament Reconstruction in Children and Adolescents

OBJECTIVE

Rupture of the anterior cruciate ligament (ACL) in childhood and adolescence is a serious injury. It is now known that conservative therapy of an unstable knee joint in childhood or adolescence under can lead to poor subjective and objective results. The aim of this study is to record long-term results after transepiphyseal ACL reconstruction using autologous hamstring tendons and extracortical fixation in childhood and adolescence with open physes - at least 15 years after surgery.

METHODS

Our internal registry was used to identify all patients who received surgical treatment of an acl tear during childhood and adolescence by transepiphyseal acl reconstruction more than 15 years previously. In these patients, the International Knee Documentation Committee for Subjective Knee Form (IKDCsubj.), Knee Injury and Osteoarthritis Outcome Score (KOOS), Tegner Activity Score (TAS) and Lysholm Score were collected, and clinical and magnetic resonance imaging (MRI) examinations were performed.

RESULTS

A total of 22 patients were identified, 5 of whom could not be contacted. The mean age at the time of surgery was 13.1 years, and the mean follow-up time was 17.4 years. In 3 patients, a traumatic tear was observed with subsequent reconstruction of the ACL. None of the included patients showed a growth disorder during the course of the study. The IKDC_subj. was 92.4 ± 14.7 (48 - 100), the Lysholm score was 87.9 ± 16.9 (34 - 100), the TAS was 5.7 ± 2.3 (3 - 9) and the pain level based on VAS was 3.5 ± 2.6 (1 - 8) points. The values showed subjective and objective deterioration compared to the 10-year results, with no statistical significance. The following subscores were reported for the KOOS: KOOS_pain 90.9 ± 17.6 (28 - 100); KOOS_symptom 82.9 ± 22.6 (11 - 100); KOOOS_ADL 94.3 ± 13.7 (44 - 100); KOOS_Sport 80.3 ± 26.4 (15 - 100); KOOS_QOL 80.9 ± 25.8 (0 - 100). 13 of the 17 patients could also be clinically and radiologically examined. In 92% of patients, an intact acl reconstruction was found without evidence of cartilage or meniscus damage. The mean lateral difference in the KT-1000 measurement was 1.5 mm.

CONCLUSION

ACL reconstruction in childhood and adolescence provides good functionality and stability of the knee joint over the long term. Secondary signs of osteoarthritis can only be detected in isolated cases by MRI. ACL reconstruction using the transepiphyseal technique can be considered the method of choice for open growth plate knee joints.

Anterior Cruciate Ligament Rupture in Skeletally Immature Patients

In the past 20 years, sports injuries in pediatric and adolescent athletes have increased dramatically, with anterior cruciate ligament (ACL) injuries accounting for more than 25% of all knee injuries at this age. Diagnosis is based on detailed clinical history, physical examination, and imaging assessment, where magnetic resonance imaging plays a central role. The growing immature skeleton presents specific characteristics, which require unique methods for surgical reconstruction, ideally avoiding the physes or minimizing the risk of damaging them. Specific rehabilitation protocols are needed, and these patients face a higher risk of recurrent and contralateral ACL injury. Nonsurgical treatment or delayed reconstruction has been associated with persistent instability, activity modifications, worst functional outcomes, and increased risk of irreparable injuries to menisci and articular cartilage. Consequently, surgical stabilization is the preferred treatment for most patients, despite the eventual risk of angular deformities or limb-length discrepancies due to iatrogenic physeal injury. A variety of surgical techniques have been described, depending on the skeletal maturity and growth remaining. Targeted prevention programs play a key role in reducing the risk of ACL injury, are easy to implement, and require no additional equipment. High-quality evidence supports its use in all pediatric athletes.

Unique Considerations for the Pediatric Athlete During Rehabilitation and Return to Sport After Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament (ACL) injuries and surgical intervention in the pediatric population have increased in the recent years. Although surgical techniques have advanced, evidence-based rehabilitation guidelines that consider all aspects of the youth athlete are currently lacking. The purpose of this commentary is to review the current evidence on unique considerations for the pediatric and adolescent population during rehabilitation and return to sport after ACL reconstruction (ACLR), with a focus on children under 18 years of age. This review revealed that returning a youth athlete to sport after ACLR requires knowledge and appreciation of various aspects of the growing athlete different from adults. In addition to postoperative precautions that contribute to a slow rehabilitation process, young athletes need additional time for strength gains. Address risk of reinjury and for contralateral injury by using neuromuscular training and rigorous return-to-sport training programs. Consider return to sport after 9 months because the reinjury rate is high in this population. A combination of time and objective measures, both quantitative and qualitative criteria, and psychological readiness should be used to assess readiness to return to sport and decrease risk of future injury. Healthcare providers should be aware of the psychosocial impact of injury on the youth athletes and refer to sport psychology when necessary.

LEVEL OF EVIDENCE

Level V.

Adolescents Have Twice the Revision Rate of Young Adults After ACL Reconstruction With Hamstring Tendon Autograft: A Study From the Swedish National Knee Ligament Registry

Background:

Previous studies have identified young age as a risk factor for anterior cruciate ligament (ACL) revision. However, few studies have looked separately at pediatric patients and adolescents with regard to outcomes after ACL reconstruction.

Purpose:

To determine whether patient age at ACL reconstruction affects the risk of undergoing revision surgery in young patients.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

This study was based on data from the Swedish National Knee Ligament Registry. Patients aged 5 to 35 years who underwent a primary ACL reconstruction with a hamstring tendon autograft between January 1, 2005, and December 31, 2015, were included. The cohort was stratified into different age groups of pediatric patients, adolescents, and young adults to estimate patients with open, recently closed, and closed epiphyses, respectively. The primary endpoint was ACL revision. A multivariable Cox regression model was used to assess the ACL revision rate. The results were expressed as hazard ratios (HRs) and 95% CIs.

Results:

A total of 36,274 ACL reconstructions were registered during the study period. Of these, 2848 patients were included in the study: 47 pediatric patients (mean age, 13.6 years; range, 9-15 years), 522 adolescents (mean age, 17.4; range, 14-19 years), and 2279 young adults (mean age, 27.0; range, 20-35 years). A total of 31 patients (1.1%) underwent ACL revision within 2 years (0 pediatric patients, 9 adolescents [1.7%], and 22 young adults [1.0%]) and a total of 53 patients (2.6%) underwent ACL revision within 5 years (2 pediatric patients [6.9%], 15 adolescents [3.9%], and 36 young adults [2.2%]). The adolescent age group had a 1.91 times higher rate of ACL revision compared with the young adults (HR = 1.91 [95% CI, 1.13-3.21]; P = .015). There were no differences in revision rates between the pediatric age group and the young adults (HR = 2.93 [95% CI, 0.88-9.79]; P = .081).

Conclusion:

Adolescents had almost twice the rate of revision ACL reconstruction compared with young adults.

Implementing ACL Injury Prevention in Daily Sports Practice-It's Not Just the Program: Let's Build Together, Involve the Context, and Improve the Content

Although the benefits of current anterior cruciate ligament (ACL) injury prevention programmes have been demonstrated in efficacy studies, they, unfortunately, have had limited public health impact to date. For example, the incidence of ACL injuries continues to rise in adolescent athletes. Raising awareness and educating coaches and athletes is not enough to facilitate the widespread, sustained use of these programmes in the real-world setting. Considering the profound burden of ACL injuries, it is necessary to continue to improve the current ACL injury prevention programmes through co-creation. First, the uptake of the programmes should be optimized by a better appreciation and understanding of the individual, socio-cultural and environmental context (i.e., community). Second, the content of the programmes should be optimized to better reflect the demands of the sport by creating more ownership and increasing motivation (incorporating challenging, sport-specific and fun elements) with the end-users. In addition, implicit motor learning, random practice and differential learning are concepts that should be integrated when practising to obtain the most optimal results when learning or finetuning skills.

Tibial Tubercle Apophyseal Stage to Determine Skeletal Age in Pediatric Patients Undergoing ACL Reconstruction: A Validation and Reliability Study

Background:

Anterior cruciate ligament (ACL) injuries demand individualized treatments based on an accurate estimation of the child’s skeletal age. Wrist radiographs, which have traditionally been used to determine skeletal age, have a number of limitations, including cost, radiation exposure, and inconvenience.

Purpose:

To evaluate the reliability and validity of a radiographic staging system using tibial apophyseal landmarks as hypothetical proxies for skeletal age to use in the preoperative management of pediatric ACL tears.

Study Design:

Cohort study (diagnosis); Level of evidence, 2.

Methods:

The study included children younger than 16 years of age who underwent ACL reconstruction between July 2008 and July 2018 and received both skeletal age radiography and knee radiography within 3 months of each other. Skeletal age was calculated from hand and wrist radiographs using the Greulich and Pyle atlas. Tibial apophyseal staging was categorized into 4 stages: cartilaginous stage (stage 1), apophyseal stage (stage 2), epiphyseal stage (stage 3), and bony/fused stage (stage 4). Data were collected by 2 independent assessors. The analysis was repeated 1 month later with the same assessors. We calculated descriptive statistics, measures of agreement, and the correlation between skeletal age and apophyseal stage.

Results:

The mean chronological age of the 287 patients included in the analysis was 12.9 ± 1.9 years; 164 (57%) of the patients were male. The overall Spearman r between skeletal age and tibial apophyseal staging was 0.69 (0.77 in males; 0.60 in females). The interrater reliability for the tibial apophyseal staging was substantial (Cohen κ = 0.66), and the intrarater reliability was excellent (Cohen κ = 0.82). The interrater reliability for skeletal age was excellent (intraclass correlation coefficient [ICC] = 0.93), as was the intrarater reliability (ICC = 0.97).

Conclusion:

The observed correlation between skeletal age and tibial apophyseal staging as well as observed intra- and interrater reliabilities demonstrated that tibial apophyseal landmarks on knee radiographs may be used to estimate skeletal age. This study supports the validity of knee radiographs in determining skeletal age and provides early evidence in certain clinical presentations to simplify the diagnostic workup and operative management of pediatric knee injuries, including ACL tears.

Pediatric ACL Revision Using Salvaged Iliotibial Band Autograft in a Physeal-Sparing Multiligamentous Knee Reconstruction: A Case Report

CASE

Iliotibial band (ITB) autograft is used for anterior cruciate ligament (ACL) reconstruction in prepubescent patients. No reports have described ITB salvage techniques for failed reconstruction. We describe a 13-year-old boy who sustained a multiligamentous knee injury, experienced a failed primary reconstruction, and required a revision ITB ACL, lateral collateral ligament, and posterior lateral corner reconstruction with reuse of his ITB autograft. At the 2-year follow-up, he returned to playing competitive sports.

CONCLUSION

This case shows that salvage of an ITB ACL autograft can be an option in early reconstruction failure.

Anterior Cruciate Ligament Injury Incidence in Adolescent Athletes: A Systematic Review and Meta-analysis

BACKGROUND

The incidence of anterior cruciate ligament (ACL) injuries among adolescent athletes is steadily increasing. Identification of the highest risk sports for ACL injuries by sex and competitive setting (ie, practice vs match) is important for targeting injury prevention programs.

PURPOSE

To identify the risk of ACL injuries in adolescent athletes by sport, sex, and setting across a variety of common US and international sports.

STUDY DESIGN

Meta-analysis.

METHODS

Essentially, 3 online databases (PubMed, Embase, and Cochrane Library) were searched for all studies of ACL injuries per athlete-exposure (AE) or hours of exposure in adolescent athletes. Injuries were then pooled and incidence rates (IRs) reported per 1000 AEs or hours of exposure, with the relative risk (RR) of injuries calculated for sex-comparable sports. IRs per competitive setting (match vs practice) were also calculated.

RESULTS

A total of 1235 ACL injuries over 17,824,251 AEs were identified (IR, 0.069 [95% CI, 0.065-0.074]), with 586 of these injuries in girls across 6,986,683 AEs (IR, 0.084 [95% CI, 0.077-0.091]) versus 649 injuries in boys over 10,837,568 AEs (IR, 0.060 [95% CI, 0.055-0.065]). Girls had a higher overall rate of ACL injuries (RR, 1.40 [95% CI, 1.25-1.57]), with the most disproportionate risk observed in basketball (RR, 4.14 [95% CI, 2.98-5.76]). The risk of ACL injuries by sex was highest in girls' soccer (IR, 0.166 [95% CI, 0.146-0.189]) and boys' football (IR, 0.101 [95% CI, 0.092-0.111]). ACL injuries were over 8 (RR, 8.54 [95% CI, 6.46-11.30]) and 6 (RR, 6.85 [95% CI, 5.52-8.49]) times more likely to occur in a match versus a practice setting for female and male athletes, respectively.

CONCLUSION

The risk of ACL injuries overall approached nearly 1 per 10,000 AEs for female athletes, who were almost 1.5 times as likely as male athletes to suffer an ACL injury across all adolescent sports. A multisport female athlete was estimated to have a nearly 10% risk of ACL injuries over her entire high school or secondary school career. Specifically, male and female adolescents playing soccer, basketball, lacrosse, and football appeared at particular risk of injuries, a finding that can be used to target an injury intervention.

Trends of anterior cruciate ligament reconstruction in children and young adolescents in Italy show a constant increase in the last 15 years

PURPOSE

The aim of this 15-year nationwide study was to investigate the trend in ACL reconstructive surgeries in patients younger than 15 years old in Italy, as well as their social and economic impact.

MATERIALS AND METHODS

The National Hospital Discharge records (SDO) collected by the Italian Ministry of Health in the 15-year period between 2001 and 2015 were analyzed. This contains anonymous data including patients' age, gender, ICD-9-CM codes for diagnosis and intervention, census region, region of hospitalization, length of the hospitalization, and public or private reimbursement.

RESULTS

1,350 ACL reconstructions were performed in Italy in the population younger than 15 years old, with an incidence rate ranging from 0.16 to 2.04 procedures per 100,000 age-matched individuals. Similarly, the percentage of surgeries in 0-14 year old patients increased with respect to the total number of ACL reconstruction from 0.13% in 2001 to 0.95% in 2015. The age range 10-14 years is the most involved, accounting for 97.3% of surgeries recorded in the study period. The male:female ratio was 1.05 and most of these procedures were performed in the North of Italy (78.3%).

CONCLUSION

ACL reconstructions in patients aged 10-14 years are increasing constantly since 2001, and thus, specific actions aimed to define the best management strategy as well as national educational programs to prepare the future surgeons to this new reality are mandatory in the interest of the public health.

LEVEL OF EVIDENCE

Level III.

Paediatric anterior cruciate ligament injury

The number of paediatric anterior cruciate ligament injuries is rising at a greater rate than in the adult population, as a result of the increased participation of children and adolescents in sports. This review explores the key presentations, diagnostic and management plans, and prevention methods associated with paediatric anterior cruciate ligament injuries. This injury presents as an acute pop and effusion, with limitations in gait, and can be extremely debilitating. Clinical examination and magnetic resonance imaging are used to diagnose the injury. The pivot shift and Lachman test remain the most valid exams when suspecting an anterior cruciate ligament tear. Management of the injury can be surgical or non-surgical depending on the severity of the tear and associated injuries. The surgical approach chosen is determined by the patient's Tanner classification, considering potential damage to the physes of the bone. Management plans should include rehabilitation consisting of strength, proprioception and neuromuscular training, to maximise the patient's recovery. Injury prevention programmes, consisting of strength training and neuromuscular training, should be followed by young athletes to reduce anterior cruciate ligament injuries. Compliance and earlier implementation coupled with an understanding of the biomechanics of anterior cruciate ligament injuries and verbal feedback maximise the benefit of neuromuscular training.

Magnetic Resonance Imaging Predictive Model Determines Hamstring Autograft Size for Anterior Cruciate Ligament Reconstruction in Patients Under 18 Years Old

Purpose

To evaluate the predictive value of magnetic resonance imaging in determining hamstring autograft size preoperatively for pediatric anterior cruciate ligament reconstruction.

Methods

We conducted an analysis of patients younger than 18 years who underwent quadrupled hamstring autograft anterior cruciate ligament reconstruction. Semitendinosus tendon (ST) and gracilis tendon (GT) cross-sectional areas were measured on preoperative knee magnetic resonance imaging scans. Height, weight, body mass index, and sex were analyzed using ordinal regression analysis. A classification and regression tree (CART) was constructed to identify predictors of the predetermined intraoperative graft size of 8 mm or greater. Sensitivity and specificity were determined based on specified predictors.

Results

This study included 102 patients (52 female and 50 male patients). The average age was 15.8 ± 1.4 years. At the time of surgery, 38 patients (37.3%) had open physes, with an average age of 13.4 ± 0.96 years. Of the 102 patients, 55 (53.9%) had 8-mm or larger grafts, 31 (30.4%) had 7.5-mm grafts, and 16 (15.7%) had 7-mm or smaller grafts. In 12 patients (31.6%) with open physes, the graft size was less than 8 mm. Male patients were more likely to have 8-mm or larger grafts (P < .001), as were patients with a greater height (170.1 ± 7.3 cm vs 161.1 ± 12.0 cm, P = .013) and those with a greater weight (79.7 ± 23.4 kg vs 57.1 ± 16.2 kg, P = .005). For all patients, predictive modeling determined that if the cross-sectional areas of the ST and GT were 31.2 mm² or greater, then 87.5% of patients would have a graft size of 8 mm or greater with an 80% sensitivity and 74% specificity. Similarly, if the cross-sectional areas of the ST and GT were 31.4 mm² or greater in patients with open physes, then 100% of patients would have a graft size of 8 mm or greater with a 46% sensitivity and 99% specificity.

Conclusions

A preoperative summation of the cross-sectional areas of the ST and GT greater than 31 mm² in patients younger than 18 years with open or closed physes can help the surgeon preoperatively predict which patients will have an intraoperative graft size of 8 mm or greater. The risk factors for a smaller graft size include female sex, a shorter height, and a lighter weight.

Level of Evidence

Level III, retrospective comparative study.

Complications and Controversies in the Management of 5 Common Pediatric Sports Injuries

Growing participation in sports among children, along with increasingly intense training regimens, has contributed to an increasing rate of sports-related injuries. Despite the similarities to adult sports injuries, pediatric patients have distinctive injury patterns because of the growing physis and therefore necessitate unique treatment algorithms. Caring for these injured children requires in-depth knowledge of not only pediatric injury patterns, but also the scope of age-specific treatments, the associated complications, and the controversies. When treating motivated pediatric athletes, one must be able to strike a delicate balance between patients' eagerness to return to sport and the need to ensure their long-term health and function. Knowledge of controversies and complications will help both patients and physicians make informed decisions about how best to restore pediatric athletes back to health.

Patient expectations and perceived social support related to return to sport after anterior cruciate ligament reconstruction in adolescent athletes

OBJECTIVE

Examine the relationship between pre-operative competitive status and return to sport expectations post-operatively among adolescents undergoing ACL reconstruction. Assess the association between perceived levels of social support and doubts in returning to sport after ACL reconstruction.

DESIGN

Cross-sectional.

SETTING

Outpatient sports medicine clinic at a single institution.

PARTICIPANTS

12-18 years old with an ACL tear who were planning to undergo ACL reconstruction.

MAIN OUTCOME MEASURES

Psychovitality questionnaire responses and Multidimensional Scale of Perceived Social Support (MSPSS) questionnaire scores.

RESULTS

86% of participants expected to return to sports in six months or less after surgery; there was no significant difference in expected time to return to sport between competitive vs. recreational athletes. Competitive athletes were less likely to be content returning to a lower activity level after surgery compared to recreational athletes. There were no significant differences in MSPSS scores between those who did and did not report doubts in their ability to return to their previous sports.

CONCLUSION

Most of our adolescent athlete population expected to return to sport after ACL reconstruction within six months of surgery. Those with and without doubts in their ability to return to sports did not significantly differ in levels of perceived social support.

The Use of Psychological Patient Reported Outcome Measures to Identify Adolescent Athletes at Risk for Prolonged Recovery Following an ACL Reconstruction

BACKGROUND

Psychological response to injury and the recovery process impact return to play and can put an athlete at risk for prolonged recovery. The purpose of this study was to investigate the psychological changes that occur surrounding an anterior cruciate ligament (ACL) reconstruction utilizing a set of patient reported outcomes measures (PROMs) that focus on psychological factors.

METHODS

Consecutive patients undergoing a primary ACL reconstruction, ages 12 to 18, were recruited. Patients were included if they verbalized a desire to return to the same sport and a baseline Tegner of >6. Functional and psychological PROMs were administered preoperatively, 6 months, and 1 year postoperatively. A Y-Balance Test was utilized to assess for clearance.

RESULTS

Of the 68 participants, 36 were female (52.9%) and 32 male, with a mean age of 14.5 years. On average, participants were cleared to return to sport 259.1 days postoperatively. Of the measures given preoperatively, only the Athletic Coping Skills Inventory-28 (ACSI)-28 correlated with delayed recovery time (rs=-0.291, P=0.04). Lower baseline ACSI-28 subscale scores in coachability (rs=-0.298, P=0.03) and Coping with Adversity (rs=-0.341, P=0.01) were correlated with delayed recovery. Participants that took longer than average to recover scored significantly lower on the ACSI-28 preoperatively than those with a shorter recovery time (62.04 vs. 54.8, P<0.01). Participants that scored <58 on their preoperative ACSI-28 took 2 months longer to recover than participants who scored ≥58 (9.6 vs. 7.65 mo, P<0.01). At 6 months postoperatively, higher ACSI-28 subscale Concentration (rs=-0.357, P<0.01) and Peaking Under Pressure (rs=-0.274, P=0.04) scores correlated with shorter recovery time.

CONCLUSIONS

The ACSI-28 significantly correlated with recovery time following ACL reconstruction. A baseline score of 58 may be a valuable cutoff to identify youth athletes at risk for prolonged recovery.

LEVEL OF EVIDENCE

Level II-prospective study.

Anterior Cruciate Ligament Injuries in Skeletally Immature Patients: A Meta-analysis Comparing Repair Versus Reconstruction Techniques

BACKGROUND

Anterior cruciate ligament (ACL) surgery remains challenging in the skeletally immature patient. Despite the widespread use of physeal-sparing reconstruction techniques, there has been renewed interest in the ACL repair. The purpose of this study was to systematically review the literature to better understand outcomes following all-epiphyseal (AE) reconstruction to extraphyseal reconstruction, while also evaluating ACL repair outcomes in skeletally immature patients.

METHODS

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, all studies in the literature from January 1970 to August 2019 reporting on skeletally immature patients undergoing ACL surgery were identified. Inclusion criteria were pediatric patients with open physes indicative of skeletal immaturity sustaining complete ACL ruptures treated with AE reconstruction, extraphyseal reconstruction or ACL repair. Chronologic age, bone age, postoperative outcomes scores, return to sport rate, and the incidence of complications, namely reruptures, were analyzed.

RESULTS

A total of 14 studies comprising 443 patients were identified. No significant difference in chronologic age or postoperative outcome scores at final follow-up were appreciated between patients undergoing AE versus extraphyseal reconstruction. Return to activity rate was significant greater following extraphyseal reconstruction when compared with AE reconstruction. The incidence of any limb-length discrepancies and limb discrepancies measuring ≥10 mm were significant higher following AE reconstruction, while rerupture rates were more common following AE reconstruction.

CONCLUSIONS

Patients undergoing AE reconstruction possessed significantly lower return to activity rates, higher incidences of limb-length discrepancies and more commonly experienced ACL reruptures when compared with patients undergoing extraphyseal reconstruction. Further investigations analyzing results following ACL repair in skeletally immature patients are warranted to allow for the comparison of outcomes with current physeal-sparing reconstruction techniques.

LEVEL OF EVIDENCE

Level IV-systematic review-therapeutic study.

ACL Growth With Age in Pediatric Patients: An MRI Study

BACKGROUND

There is limited knowledge of morphologic changes of the anterior cruciate ligament (ACL) during childhood. The purpose of the study is to describe normal ACL growth in pediatric patients.

METHODS

We performed retrospective review of patients under 19 years of age with at least 2 serial magnetic resonance imaging (MRI) examinations of the same knee without ACL tear. The parameters measured included length of the ACL, width of the ACL in sagittal and coronal planes, physeal status, ACL-tibial inclination angle, Notch Width Index, ACL tibial attachment width and midpoint, and anterior to posterior length and height of the tibial epiphysis. Pearson correlation coefficients were calculated to determine the strength of correlation of each parameter relative to age. Growth curves were calculated for individual parameters, producing a predictive model for growth of the ACL over time.

RESULTS

One hundred forty-seven patients (365 MRIs) were included. The average age at initial MRI was 12.2 years (range: 1.2 to 18.4 y). The Pearson correlation coefficient for each parameter was statistically significant relative to age. Younger patients had more oblique, anteriorly attached ACLs. Three distinct phases of growth were observed: patients age 1.5 to 5.75 years average 2.25 mm of growth per year; patients aged 6 to 11.5 average 1.46 mm of growth per year; growth slows at age 11.75, stopping by 18.5 years. The growth model for ACL sagittal width increased 0.45 mm/y from age 1.5 to 14.5 after which it plateaus, whereas coronal width increased 0.22 mm/y from age 1.5 to 18.75.

CONCLUSIONS

In the pediatric patient, the ACL grows in length and width in a predictable manner until age 18. This model aids clinicians in predicting normal ACL parameters for anatomic reconstruction procedures in the skeletally immature patient.

LEVEL OF EVIDENCE

Level IV.

ACL Injuries Aren't Just for Girls: The Role of Age in Predicting Pediatric ACL Injury

BACKGROUND

Female athletes have a higher rate of anterior cruciate ligament (ACL) injuries than male athletes; however, the role of age in mediating this injury risk has not been explored. The purpose of this study was to characterize the relationship between age and sex in predicting ACL injury in the pediatric population.

HYPOTHESIS

Prepubescent boys are more likely to sustain an ACL injury than prepubescent girls.

STUDY DESIGN

Descriptive epidemiological study.

LEVEL OF EVIDENCE

Level 4.

METHODS

Data were collected from the Statewide Planning and Research Cooperative System database for the state of New York from 1996 to 2016. The database was queried for patients aged ≤19 years who had been diagnosed with an ACL tear using the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) code 844.2 or the ICD-10 (10th Revision) codes S83.512A/S83.511A/S83.519A. Patient age and sex at time of ACL injury diagnosis were recorded. Chi-square analysis was used to compare the frequency of ACL injury between groups, with statistical significance set atP < 0.05.

RESULTS

A total of 20,128 patients aged ≤19 years were diagnosed with an ACL tear (10,830 males, 9298 females; male:female, 1.16:1). In all, 129 patients aged <12 years sustained an ACL tear (85 boys, 44 girls; male:female, 1.93:1), and 19,999 of those patients were aged 12 to 19 years (10,745 males, 9254 females; male:female, 1.16:1). Chi-square analysis demonstrated a significant relationship between sex and age group (P < 0.006). Additional analysis revealed that female athletes were most at risk for ACL injury from ages 12 to 16 years, with 4025 male and 5095 female athletes sustaining ACL injuries in this group (male:female, 1:1.27; P < 0.0001).

CONCLUSION

Prepubescent boys (aged <12 years) are more likely to sustain an ACL injury than same-aged female peers.

CLINICAL RELEVANCE

This study demonstrates that the risk of ACL injury varies with age and sex throughout childhood and adolescence, further guiding treatment and prevention for these pediatric athletes.

Deep Learning Approach for Anterior Cruciate Ligament Lesion Detection: Evaluation of Diagnostic Performance Using Arthroscopy as the Reference Standard

BACKGROUND

MRI is the most commonly used imaging method for diagnosing anterior cruciate ligament (ACL) injuries. However, the interpretation of knee MRI is time-intensive and depends on the clinical experience of the reader. An automated detection system based on a deep-learning algorithm may improve interpretation time and reliability.

PURPOSE

To determine the feasibility of using a deep learning approach to detect ACL injuries within the knee joint on MRI.

STUDY TYPE

Retrospective.

POPULATION

In all, 163 subjects with an ACL tear and 245 subjects with an intact ACL. There were 285, 81, and 42 volumes for training, validation, and test sets, respectively.

FIELD STRENGTH/SEQUENCE

2D sagittal proton density-weighted spectral attenuated inversion recovery sequences at 1.5T and 3.0T.

ASSESSMENT

Based on the architecture of 3D DenseNet, we constructed a classification convolutional neural network. We tested this deep learning approach with different inputs and two other algorithms, including VGG16 and ResNet. Then we had both inexperienced radiologists and senior radiologists read the MR images.

STATISTICAL TESTS

Using arthroscopic results as the reference standard, the performance of three different inputs and three different algorithms, the residents and senior radiologists assessed the classification accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the receiver operating characteristic curve (AUC).

RESULTS

The accuracy, sensitivity, specificity, PPV, and NPV of our customized 3D deep learning architecture was 0.957, 0.976, 0.944, 0.940, and 0.976, respectively. The average AUCs were 0.946, 0.859, 0.960 for ResNet, VGG16, and our proposed network, respectively. The diagnostic accuracy of our model, residents, and senior radiologists was 0.957, 0.814, and 0.899, respectively.

DATA CONCLUSION

Our study demonstrated the feasibility of using an automated deep-learning-based detection system to evaluate ACL injury.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY STAGE: 1 J. MAGN. RESON. IMAGING 2020;52:1745-1752.

Anterior Cruciate Ligament Re-tear and Revision Reconstruction in the Skeletally Immature Athlete

PURPOSE OF REVIEW

With an increase in high-demand sporting activity, the rate of pediatric and adolescent anterior cruciate ligament (ACL) reconstruction is increasing. Yet, the failure rates after reconstruction are much higher than the adult population. The purpose of this paper is to understand failure rates, reasons for graft failure, and strategies for successful revision surgery.

RECENT FINDINGS

A complete understanding of the failure etiology is essential for the clinician treating this population prior to revision. This begins with an assessment of post-operative patient compliance and sporting activity. Surgical technique must then be scrutinized for non-anatomic tunnel placement and poor graft size/type. Concurrent bony deformity must also be addressed including lower extremity valgus alignment and tibial slope abnormalities. Meniscus and chondral injury must be aggressively treated. Furthermore, imaging must be examined to look for missed posterolateral corner injury. Lateral extra-articular tenodesis (in the setting of ligamentous laxity or rotational instability) may be also indicated as well. The surgeon can then choose a graft type and surgical technique that optimizes outcome and respects skeletal growth. Prior to surgical intervention, the clinician must also counsel patients in regard to the guarded prognosis and outcomes in this setting. Prolonged rehabilitation protocols/return-to-play timing as well as sporting activity modification in the post-operative period after revision are critical. There is limited literature on revision ACL reconstruction in the skeletally immature athlete. An understanding of all the risk factors for failure is essential in order to achieve treatment success.

Quadriceps Neuromuscular and Physical Function After Anterior Cruciate Ligament Reconstruction

CONTEXT

Persistent neuromuscular deficits in the surgical limb after anterior cruciate ligament reconstruction (ACLR) have been repeatedly described in the literature, yet little is known regarding their association with physical performance and patient-reported function.

OBJECTIVE

To describe (1) interlimb differences in neuromuscular and functional outcomes and (2) the associations of neuromuscular outcomes with measures of physical and knee-related patient-reported function.

DESIGN

Cross-sectional study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

Thirty individuals after primary, unilateral ACLR (19 males; age = 21.5 years [range, 14-41 years]; 8 months [range = 6-23 months] postsurgery).

MAIN OUTCOME MEASURE(S)

Knee-extensor isometric and isokinetic peak torque was measured with an isokinetic dynamometer. Cross-sectional area (CSA) was measured bilaterally for each of the quadriceps muscles via magnetic resonance imaging. We measured quadriceps central activation bilaterally via the superimposed-burst technique. Physical performance (single-legged hop tests, step length via spatiotemporal gait analysis) and patient-reported outcomes (International Knee Documentation Committee questionnaire and Knee Injury and Osteoarthritis Outcome Score Sport and Recreation subscale) were also recorded. We conducted Wilcoxon signed rank tests to identify interlimb differences. Spearman ρ correlation analyses revealed associations between limb symmetry and neuromuscular and functional outcomes, as well as with patient-reported function.

RESULTS

Deficits in the surgical limb as compared with the nonsurgical limb were present for all outcomes (P values < .05). Greater single-legged hop-test symmetry (83%) was significantly correlated with greater symmetry in knee-extensor isometric (63%; r_s = 0.567, P = .002) and isokinetic (68%; r_s = 0.540, P = .003) strength, as well as greater cross-sectional area of the vastus medialis (78%; r_s = 0.519, P = .006) and vastus lateralis (82%; r_s = 0.752, P < .001). A higher International Knee Documentation Committee questionnaire score (82.2) was significantly correlated with greater symmetry in knee-extensor isokinetic strength (r_s = 0.379, P = .039).

CONCLUSIONS

Although deficits were observed in the surgical limb for all neuromuscular measures, greater symmetry in the size and strength of the quadriceps, rather than activation, was more strongly associated with physical performance after ACLR. Greater symmetry in strength was also more strongly associated with patient-reported function.

Weight Gain After ACL Reconstruction in Pediatric and Adolescent Patients

BACKGROUND

Adolescent athletes who sustain an anterior cruciate ligament (ACL) tear have significantly reduced activity levels during recovery. Activity level is linked to body mass index (BMI); however, it is unclear how recovery from an ACL reconstruction (ACLR) affects relative BMI and whether these changes persist after return to activity.

HYPOTHESIS

Patients' BMI percentile will significantly increase after ACLR, but will trend toward baseline after return to activity.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

A retrospective review of 666 pediatric and adolescent patients who underwent ACLR was performed. Body mass was assessed by evaluating change in BMI percentile at 8 standard-of-care time windows relative to BMI percentile at time of surgery. Linear regression and bivariate and multivariate analyses were used to assess the effect of time window and other demographic factors on the change in BMI percentile. These analyses were rerun after dividing patients by clinical obesity categorization (underweight, normal, overweight, or obese) at time of surgery to assess the effect of preinjury body mass levels.

RESULTS

BMI percentile of all BMI categories tended to increase postoperatively, peaking 6 to 9 months after surgery, with a median increase of 1.83 percentile points. After this peak, BMI approached baseline but remained elevated at 0.95 percentile points 2 years postoperatively. Beginning 3 months after surgery, the normal-weight group had significantly larger changes in BMI percentile at each time window, peaking at 4.15 points above baseline at 9 months. This BMI increase among normal-weight patients persisted in the second postoperative year, with a median percentile increase of 2.63 points.

CONCLUSION

Pediatric and adolescent patients, especially those with a normal BMI, undergo significant changes to their BMI during recovery from ACLR.

CLINICAL RELEVANCE

Patients' failure to return to their presurgical BMI percentile 2 years postoperatively suggests that ACLR may have long-reaching and often unappreciated effects on body mass.

Marked increase in the incidence of anterior cruciate ligament reconstructions in young females in New Zealand

BACKGROUND

Anterior cruciate ligament injuries cause significant morbidity, and may be increasing in incidence as participation in high-risk sports increases. The aim of this study is to investigate the incidence of anterior cruciate ligament reconstruction (ACLR) surgery in New Zealand, and to analyse changes over time in demographic subgroups.

METHOD

Data were sourced from the Accident Compensation Corporation. Data relating to primary ACLRs performed from 2009 to 2016 were evaluated (n = 20 751). Baseline population estimates were obtained from national census data to calculate the incidence, and results were compared to previous data from 2000 to 2005 (n = 7375).

RESULTS

The annual incidence of ACLR for 2009-2016 was 58.2 per 100 000 person-years and was greater in males than in females (72.2 and 44.9, respectively). This represents a 58% increase when compared with the period 2000-2005 (36.9 per 100 000). The greatest increase was seen in females aged 15-19 years, with the incidence increasing by 120% in the last decade, compared with 53% in females aged 20-24 years. The percentage of injuries caused by sports changed from 65% over 2000-2005 to 76% over 2009-2016, with netball, rugby and football accounting for the highest number of injuries.

CONCLUSION

The incidence of ACLR procedures has increased markedly in New Zealand, and this increase was most pronounced in females aged 15-19 years. A greater proportion of procedures are now due to sport-related injuries.

Pediatric ACL Tears: Natural History

BACKGROUND

Increased participation in youth sports is associated with increased rates of anterior cruciate ligament (ACL) tears in the skeletally immature. Historically, ACL reconstruction was avoided in the skeletally immature, or delayed until skeletal maturity, to avoid physeal injury and growth disturbance. Current practices and meta-analyses support early ACL reconstruction in some groups, to allow for return to activities and to avoid delayed cartilage/meniscus injury.

PURPOSE

The purpose of this article was to report on the natural history of ACL injuries in the skeletally immature.

METHODS

A review of published literature on pediatric, skeletally immature ACL tears and conservative, nonoperative treatment was conducted via Pubmed articles published from 1970 to 2018. The search criteria included the key terms "anterior cruciate ligament," "pediatric" and/or "adolescent," and "conservative" and/or "nonoperative treatment." A PRISMA workflow was used to narrow down the articles to those relevant to our analysis and available in full text format.

RESULTS

Multiple articles on the nonoperative treatment of the ACL showed secondary meniscal and cartilage damage at the time of follow-up. Some articles showed no difference between the rates of secondary injuries between the surgical and nonsurgical treatment groups; however, the nonsurgical treatment groups were often on significant activity modification. Some articles concluded that nonoperative treatment of the ACL tear may be appropriate in low risk, lower level activity patients, and those that will comply with activity restrictions. Even with bracing and PT programs, active athletes treated without surgery appear to have a concerning rate of secondary meniscus injury after the primary ACL injury event.

CONCLUSIONS

The natural history of the ACL tear shows nonoperative treatment for the skeletally immature may be a viable treatment pathway for those who are able to comply with the physical activity restrictions. For the general population of young, active adolescents, an ACL injury treated nonoperatively often leads to secondary meniscal and/or cartilage damage, which may lead to knee degeneration and functional instability.

Patient-Reported Outcome Measures for Patellofemoral Instability: a Critical Review

PURPOSE OF REVIEW

The purpose of this paper was to review the current psychometric properties of patient-reported outcome measures that are commonly used for patients with patellofemoral instability. This review provides evidence to guide the selection of subjective outcome measures for assessing outcomes in clinical care and research studies.

RECENT FINDINGS

At the present time, there are two patient-reported outcome measures that have been designed for, and tested on, large cohorts of patellofemoral instability patients, the Banff Patella Instability Instrument (BPII) and the Norwich Patellar Instability Score (NPI). The BPII is a wholistic quality of life outcome measure and the NPI is a symptom score. The use of disease-specific outcome measures such as the BPII and NPI, in combination with generic knee, functional activity, and/or psychological outcome measures that have been proven to be valid and reliable for the patellofemoral instability population, is most likely to provide a well-rounded evaluation of treatment outcomes.

Trends in Pediatric ACL Reconstruction From the PHIS Database

BACKGROUND

Previous studies have suggested that anterior cruciate ligament (ACL) reconstruction surgeries are being performed with increased frequency in children and adolescents. The purpose of this study was to evaluate the trend in the frequency of ACL reconstructions normalized by total orthopaedic surgeries at pediatric hospitals nationwide.

METHODS

The Pediatric Health Information System (PHIS) database was queried for patients age 18 years or younger who underwent orthopaedic surgery at any of the PHIS-participating hospitals 2004-2014. The subset of patients who had been treated with ACL reconstruction were identified using Current Procedural Terminology (CPT) and International Classification of Diseases, Ninth Revision (ICD-9) procedure codes. The yearly rate was expressed as the number of ACL reconstructions per 1000 orthopaedic surgeries, and a linear model was used to fit the data to illustrate the relative trend.

RESULTS

In total, 470,126 orthopaedic surgeries, including 15,231 ACL reconstructions, were performed for patients 18 years or younger at 27 pediatric hospitals. ACL reconstructions were performed at a yearly rate of 32.4 per 1000 orthopaedic surgeries. Between 2004 and 2014, the number of ACL reconstructions increased 5.7-fold, whereas orthopaedic surgeries increased 1.7-fold; there was a 2.8-fold increase in ACL reconstructions relative to total pediatric orthopaedic surgeries. The 10-year relative fold increase was nearly equivalent across sexes, and the increasing trend in ACL reconstructions relative to orthopaedic surgeries was also seen across age groups.

CONCLUSIONS

The number of ACL reconstructions performed for children and adolescents in pediatric hospitals nationwide markedly increased by nearly 3 times relative to orthopaedic surgeries over a recent 10-year period.

LEVEL OF EVIDENCE

Level IV.

Simultaneous multi-slice accelerated turbo spin echo of the knee in pediatric patients

PURPOSE

To compare knee MRI performed with the integrated parallel acquisition technique (PAT) and simultaneous multislice (SMS) turbo spin echo (TSE) T2-weighted (T2w) sequences with conventional TSE sequences in pediatric patients.

MATERIALS AND METHODS

This was a retrospective IRB-approved study. Seventy-four subjects (26 male, 48 female, mean age 15.3 years, range 8-20) underwent 3-T MRI of the knee with a T2w TSE pulse sequence prototype with four-fold PAT and SMS acceleration as well as the standard PAT-only accelerated sequences. Images were anonymized and two study folders were created: one examination with only T2w PAT2 images (conventional examination) and one examination with only T2w SMS2/PAT2 sequences (SMS examination). Two readers rated examinations for 15 specific imaging findings and 5 quality metrics. Interreader agreement was measured. Signal to noise (SNR) and contrast to noise (CNR) were measured for SMS and conventional T2w sequences.

RESULTS

Consensus review demonstrated diagnostic quality performance of SMS examinations with respect to all 15 structures. Average area under the curve (AROC) was 0.95 and 0.97 for readers 1 and 2, respectively. The conventional sequence was favored over SMS for four out of five quality metrics (p < 0.001). SNR and CNR were higher for the conventional sequences compared to SMS.

CONCLUSION

SMS accelerated T2w TSE sequences offer a faster alternative for knee imaging in pediatric patients without compromise in diagnostic performance despite diminished SNR. The four-fold acceleration of SMS is beneficial to pediatric patients who often have difficulty staying still for long MRI examinations.

Pediatric Anterior Cruciate Ligament Reconstruction

The rate of anterior cruciate ligament (ACL) ruptures diagnosed among the pediatric and adolescent population is increasing. The rise in ACL injuries may be attributed to earlier sports specialization, year-round sports participation, increased awareness, and improved ability to diagnose the injury. Treatment options for pediatric or adolescent ACL injuries include nonoperative conservative treatment, ACL repair, or various techniques for ACL reconstruction. The best course of treatment for ACL rupture in young patients continues to be debated. Anterior cruciate ligament reconstruction with autograft is currently the gold standard and has been shown to be successful in restoring joint stability. This article reviews predisposing factors, common mechanisms, diagnostic procedures, and treatments for ACL rupture in adolescent patients, with a focus on using quadriceps patellar tendon autograft. [Orthopedics. 2018; 41(3):129-134.].

Current Strategies and Future Directions to Optimize ACL Reconstruction in Adolescent Patients

The incidence of anterior cruciate ligament (ACL) injuries in the pediatric population has risen in recent years. These injuries have historically presented a management dilemma in skeletally immature patients with open physes and significant growth remaining at time of injury. While those nearing skeletal maturity may be treated with traditional, transphyseal adult techniques, these same procedures risk iatrogenic damage to the growth plates and resultant growth disturbances in younger patients with open physes. Moreover, conservative management is non-optimal as significant instabilities of the knee remain. Despite the development of physeal-sparing reconstructive techniques for younger patients, there remains debate over which procedure may be most suitable on a patient to patient basis. Meanwhile, the drivers behind clinical and functional outcomes following ACL reconstruction remain poorly understood. Therefore, current strategies are not yet capable of optimizing surgical ACL reconstruction on an individualized basis with absolute confidence. Instead, aims to improve surgical treatment of ACL tears in skeletally immature patients will rely on additional approaches in the near future. Namely, finite element models have emerged as a tool to model complex knee joint biomechanics. The inclusion of several individualized variables such as bone age, three dimensional geometries around the knee joint, tunnel positioning, and graft tension collectively present a possible means of better understanding and even predicting how to enhance surgical decision-making. Such a tool would serve surgeons in optimizing ACL reconstruction in the skeletally immature individuals, in order to improve clinical outcomes as well as reduce the rate of post-operative complications.

Anterior Cruciate Ligament Reconstruction in Skeletally Immature Patients: Early Results Using a Hybrid Physeal-Sparing Technique

Background:

Reconstruction of the anterior cruciate ligament (ACL) in the skeletally immature patient is frequently performed in hopes of preventing new or additional chondral damage and meniscal injuries. Patients within a few years of skeletal maturity are more at risk for ACL injuries than prepubescent patients, about whom several physeal-sparing techniques have been described. Reconstruction techniques in the former higher risk group need to be better understood.

Purpose:

To review a series of adolescent patients with ACL injuries surgically treated with the hybrid physeal-sparing technique.

Study Design:

Case series; Level of evidence, 4.

Methods:

Surgical logs of ACL reconstructions (ACLRs) performed at a single pediatric/adolescent sports medicine center over a 6-year period were reviewed. Patients with open physes who had undergone ACLR with a femoral physeal-sparing tunnel and transphyseal tibial tunnel were identified. Their demographics, operative reports, rehabilitative course, time to return to play, outcome scores, and postoperative radiographs were collected and analyzed.

Results:

Twenty-three patients with a mean chronological age and bone age of 13.0 and 13.6 years, respectively, were identified. Examination and subjective outcome scores were obtained at a mean of 19 months and overall demonstrated positive results, with a mean Pediatric International Knee Documentation Committee (Pedi-IKDC) score of 96.0 and a mean Anterior Cruciate Ligament–Return to Sport after Injury (ACL-RSI) score of 89.1. Full-length mechanical axis films obtained at a mean 21 months postoperatively demonstrated no leg-length discrepancies or angular deformities in 21 of 23 patients. Two patients had an identified growth disturbance in the form of femoral and tibial growth acceleration on the ACL-reconstructed limb.

Conclusion:

The femoral physeal-sparing with transphyseal tibial drilling “hybrid” technique in skeletally maturing patients appears to have a high rate of success with low morbidity. However, the possibility of physeal abnormalities does exist, which demonstrates the importance of a close postoperative follow-up and evaluation until skeletal maturity is achieved. ACLR in skeletally immature patients is performed on an increasingly regular basis. Establishing the best and safest technique to do so is therefore important.

Challenges in the Management of Anterior Cruciate Ligament Ruptures in Skeletally Immature Patients

Although initially considered rare, anterior cruciate ligament (ACL) ruptures in pediatric patients recently have increased substantially as a result of greater awareness of the injury and increased participation in youth sports. Although pediatric patients with an ACL injury and a clinically stable joint may handle the injury well and return to sports activity without requiring surgical reconstruction, young, active patients with an ACL rupture and an unstable joint may be good candidates for ACL reconstruction to prevent ongoing instability and additional joint damage. ACL reconstruction techniques have been developed to prevent physeal injury in skeletally immature patients. The surgical treatment of skeletally immature patients with an ACL rupture may differ from that of adults with an ACL rupture and presents unique challenges with regard to reconstruction technique selection, graft preparation, rehabilitation, and return to sports activity. Orthopaedic surgeons should understand various physeal-sparing ACL reconstruction techniques and the general challenges associated with the surgical management of ACL ruptures in pediatric patients.

Specialization patterns across various youth sports and relationship to injury risk

OBJECTIVES

Current trends among young athletes towards earlier specialization age and year-round training on multiple teams has raised concern for increased injury risk. Our previous analyses showed higher risk for injury in highly specialized young athletes. The goal of this research was to determine whether sports specialization and injury patterns vary by sports type.

METHODS

In this clinical case-control study, injured athletes (aged 7-18 years) were recruited from sports medicine clinics and compared to similarly aged uninjured athletes recruited from primary care clinics. Participants completed a survey reporting age, gender, sport type, specialization patterns, and details regarding sports-related injuries in the previous 6 months. Clinical diagnoses were collected from patients' medical records. Injuries were classified as acute, overuse, or serious overuse.

RESULTS

Of 1,190 athletes enrolled, 26% (313) were single-sport specialized (reported participation in one sport and trained >8 months/year). Sports with the highest proportion of single-sport specialized athletes were tennis (46.7%), gymnastics (30.1%), and dance (26.3%). Single-sport specialized athletes in individual sports started specializing at a younger age (11.2 ± 2.4 vs. 12.0 ± 2.7, p = 0.05) and reported higher training volumes (11.8 vs. 10.3 h/week, p = 0.04) than those in team sports. Sports with the youngest specialization age were gymnastics (8.9 ± 1.7), dance (10.8 ± 3.0), and soccer (10.9 ± 2.4). Single-sport specialized athletes in individual sports accounted for a higher proportion of overuse injuries (44.3% vs 32.2%, OR = 1.67, p = 0.037) and serious overuse injuries (23.4% vs 11.6%, OR = 2.38, p = 0.011), but a lower proportion of acute injuries (28.8% vs 13.8%, OR = 0.37, p = 0.001) compared to single-sport specialized athletes involved in team sports.

CONCLUSIONS

Athletes in individual sports may be more likely to specialize in a single sport than team sport athletes. Single-sport specialized athletes in individual sports also reported higher training volumes and greater rates of overuse injuries than single-sport specialized athletes in team sports.

Trends in Pediatric and Adolescent Anterior Cruciate Ligament Injuries in Victoria, Australia 2005-2015

Anterior cruciate ligament (ACL) injuries in children and adolescents have been the focus of recent media attention and parental concern, given their potential for adverse long-term health outcomes and healthcare costs. However, there is limited formal evidence on trends in the incidence of ACL injuries in children. This study utilizes the Victorian Admitted Episodes Dataset (VAED) to characterize epidemiologic trends of hospital-admitted ACL injuries in those aged 5 to 14 years over a period of 10 years from 2005 to 2015. There was a total of 320 cases and the overall annual rate of ACL injuries increased by 147.8% from 2.74 per 100,000 population in 2005/2006 to 6.79 per 100,000 in 2014/2015. The majority (96.9%) of these injuries were in 10- to 14-year-olds. The main in-hospital procedure provided to over 80% of the hospitalized cases involved ACL reconstruction. Sporting activities accounted for 56.6% of ACL injuries. For females, over half (52.4%) of ACL injuries occurred whilst playing ball sports, compared to 35.4% of males. The large increase in ACL injuries in 5- to 14-year-olds in the state of Victoria, Australia over a 10-year period indicates they are a significant and emerging health burden. Population-wide ACL prevention policies are required to halt these trends. Cost effective prevention programs that involve neuromuscular training must be implemented in schools and junior sports teams.