The number of anterior cruciate ligament (ACL) reconstructions in children continues to rise [1]. Decisions regarding how ACL injuries are managed are complex, involve shared decision-making with children and their parents/guardians, and consider the potential long-term impact of the injury and potential treatment interventions. In this blog, we provide a synthesis developed by the ReFORM IOC Research Centre [2,3] of the IOC consensus from Ardern et al. [4] that aimed to assist physicians, parents/guardians, and children with ACL injuries make informed decisions about preventing, diagnosing and managing ACL injuries. This consensus statement addresses six fundamental clinical questions regarding the prevention, diagnosis, and management of paediatric ACL injuries (Figure 1). Our summary is expanded by consideration of more recent evidence in the prevention and management of ACL injuries. 

What can the practitioner do to prevent paediatric ACL injuries?

Preventing ACL injuries and re-injuries is crucial, with responsibility falling on those involved in youth sports and practitioners treating young athletes. Prevention programs primarily target key modifiable parameters: muscle strength, plyometrics, agility, and movement quality (including jump landings and changes of direction) [5,6]. Their efficacy, when performed multiple times per week, has been shown not only by an increase in performance but also by a reduction of over half of football-related lower extremity injuries when using the FIFA 11+ For Kids [7]. Making it fun to participate in the program and implementing injury prevention programs early in the athlete’s developmental process may increase adherence. 

How does the practitioner diagnose paediatric ACL injuries?

It is essential to diagnose ACL injury accurately and promptly. Typically, a detailed patient history and clinical examination raise strong suspicion, especially with the onset of hemarthrosis within 24 hours of trauma, indicating a significant structural injury. No single clinical test or image can systematically identify an ACL injury with high reliability but, in the clinical context, they still give valuable information. Standard x-rays are indicated initially for children with knee hemarthrosis to detect fractures such as tibial spine, patellar sleeve, or tibial tuberosity fracture. An MRI is indicated if the x-ray is normal and there is high suspicion of an ACL injury but especially essential for detecting and diagnosing associated meniscus tears, ligament tears and osteochondral lesions. Immediate MRI should be done for a locked knee to evaluate for a displaced bucket handle meniscus tear or an osteochondral fracture requiring prompt surgical intervention.

What are the treatment options?

High-quality rehabilitation, or an ACL reconstruction combined with high-quality rehabilitation, are evidence-based therapeutic options. 

The primary goals of treatments are:

   1) to restore a well-functioning knee for long-lasting active lifestyle

   2) to reduce the risk of secondary injury

   3) to minimise the risk of growth arrest and lower limb deformity. 

High-quality rehabilitation

Rehabilitation, tailored to the child’s physiological and psychological maturity and in close collaboration with the child’s parents/guardians, aims to improve neuromuscular control. Rehabilitation follows a progressive, criterion-based protocol, including fun and varied exercises focused on movement quality, and lasting for at least 3-6 months for non-surgical treatment and 9-12 months after ACL reconstruction [8]. Return to sports criteria are not yet validated for skeletally immature patients, such as for movement quality, with a larger measurement error for single leg hop and isokinetic strength tests [9]. 

Main indications for ACL reconstruction:

• An associated repairable injury (i.e., meniscal or osteochondral injury)
• Recurrent instability despite completing structured high-quality rehabilitation
• Unacceptable activity limitations for the child

Surgical techniques

General surgical principles of ACL reconstruction in adults, using autografts with appropriate dimensions and fixation, also apply to paediatric patients. In skeletally immature patients, physeal protection is necessary. Various techniques aim to minimize damage to the physis, either orienting the drill tunnels perpendicular to the physis (transphyseal), avoiding drilling bone tunnels (extra-articular), staying entirely within the epiphysis (all-epiphyseal), or using hybrid techniques. Only soft tissue autografts (hamstring or quadriceps tendons) should be used, avoiding patellar tendon with bone plugs or allografts. Graft fixation must respect the physis to prevent growth disturbances. Bone blocks or hardware crossing the physis are not safe.

What are the main considerations for deciding on treatment?

• Estimating bone age and remaining growth are major factors in therapeutic decision-making. These estimates guide treatment choice, timing of intervention, and surgical method. Children’s open physes are vulnerable during surgery, and none of the currently recommended surgical treatments for children with ACL injuries can guarantee their protection or prevent potential growth disturbance or deformity.
• Children with additional repairable injuries at the time of ACL injury diagnosis (e.g., a displaced bucket handle meniscus tear) should undergo early ACL reconstruction and meniscal repair. For those without additional injuries warranting immediate surgical intervention, opinions differ on the best therapeutic approach.
• Non-surgical treatment is a viable and safe therapeutic option for skeletally immature patients without associated injuries or major instability issues, but delayed ACL reconstruction may be required over time.
• Possible risks related to surgical treatment regardless of technique are growth disturbance, ACL graft rupture, joint stiffness and infection. 
• Following both treatment options there is a risk of long-term knee problems and secondary injuries [10].

Responses to these considerations can change the decision-making process for paediatric ACL injury management, depending on the risk tolerance of the decision makers including the child, their parents/guardians, and practitioners.

How does the practitioner measure relevant outcomes?

Evaluating Patient Reported Outcomes Measures (PROMs) provides insights into aspects of a patient’s function that cannot be assessed through clinical examinations or imaging. Therefore, evaluating PROMs is crucial to managing children’s knee injuries.

The following self-reported tools are recommended for paediatric patients:

• Generic health-related quality of life measure.
• Pedi-IKDC or KOOS-Child (knee function).
• Paediatric Functional Activity Brief Scale (activity level).

What are the practitioner’s roles and responsibilities?

The practitioner should:

• Encourage the child’s support system to prioritize injury prevention, ensuring long-term health protection even in the face of short-term sports interests.
• Ensure that decisions regarding the child’s knee integrity are shared among the child, parent/guardian, and medical practitioner.
• Provide information to the child in a clear and understandable manner, tailored to their comprehension level
• Seek the child’s approval or assent, irrespective of the parent/guardian’s wishes.
• Guide discussions and provide information based on high-quality research to inform the child and their parent/guardian, leading to ethically justified treatment decisions.
• Advocate for treatment recommendations based on paediatric ethical standards, especially when consensus is lacking in the decision-making process.

Conclusion

Managing paediatric ACL injuries remains controversial. Consensus must be reached by all parties involved in the decision-making process. This consensus should be informed by a realistic assessment of risks and benefits, considering the child’s and parents’ goals. The practitioner’s responsibility is to guide this discussion with precise information from the most reliable research.

References

[1] Shaw L, Finch CF. Trends in pediatric and adolescent anterior cruciate ligament injuries in Victoria, Australia 2005-2015. Int J Environ Res Public Health 2017;14:599

[2] Martens, G., Edouard, P., Tscholl, P.M., Bieuzen, F., Winkler, L. Cabri, J., Urhausen, A., Guilhem, G., Croisier, J.L., Thoreux, P., Leclerc, S., Hannouche, D., Kaux, J.F., Le Garrec, S. & Seil, R. (2021). La traduction et la synthèse des positions de consensus du CIO :
la première mission de ReFORM pour une meilleure diffusion des connaissances vers la francophonie. J Traumatol Sport 2021 ;38(3) :127-128. 

[3] Martens, G., Edouard, P., Tscholl, P., et al. Document, create and translate knowledge: the mission of ReFORM, the Francophone IOC Research Centre for Prevention of Injury and Protection of Athlete Health. Br J Sports Med 2021; 55:187-188.

[4] Ardern, C., Ekas, G., Grindem, H., et al. 2018 International Olympic Committee consensus statement on prevention, diagnosis and management of paediatric anterior cruciate ligament (ACL) injuries. KSSTA 2018; 26: 989-1010.

[5] Emery CA, Roy TO, Whittaker JL, et al. Neuromuscular training injury prevention strategies in youth sport: a systematic review and meta-analysis. Br J Sports Med 2015;49:865–70. 

[6] Lauersen JB, Bertelsen DM, Andersen LB. The effectiveness of exercise interventions to prevent sports injuries: a systematic review and meta-analysis of randomised controlled trials. Br J Sports Med 2014;48:871–7. 

[7] Rössler R, Junge A, Bizzini M, et al. A multinational cluster randomised controlled trial to assess the efficacy of ’11+ Kids’: a warm-up programme to prevent injuries in children’s football. Sports Med 2017; 48(6):1493-1504.

[8] Grindem H, Eitzen I, Engebretsen L, Snyder-Mackler L, Risberg MA. Nonsurgical or Surgical Treatment of ACL Injuries: Knee Function, Sports Participation, and Knee Reinjury: The Delaware-Oslo ACL Cohort Study. J Bone Joint Surg Am. 2014 ;96(15):1233-1241. 

[9] Dekker TJ, Godin JA, Dale KM, Garrett WE, Taylor DC, Riboh JC. Return to Sport After Pediatric Anterior Cruciate Ligament Reconstruction and Its Effect on Subsequent Anterior Cruciate Ligament Injury. J Bone Joint Surg Am. 2017; 99(11):897-904. 

[10] Moksnes H, Engebretsen L, Risberg MA. Prevalence and Incidence of New Meniscus and Cartilage Injuries After a Nonoperative Treatment Algorithm for ACL Tears in Skeletally Immature Children: A Prospective MRI Study. Am J Sports Med 2013;41(8):1771-1779. 

Authors:

de Garie (1,2), C. Ardern (3,4), L. Engebretsen (9), C. Tooth (1,5,6), R. Seil (1,7,8), G. Ekås (9,10,11), H. Moksnes (10), H. Grindem (10,12), P. Tscholl (1,13), F. Delvaux (1,5,6)

Affiliations:

1 ReFORM IOC Research Centre for Prevention of Injury and Protection of Athlete Health

2 Institut National du Sport du Québec, Montréal, Canada

3Division of Physiotherapy, Linköping University, Linköping, Sweden. 

4School of Allied Health, La Trobe University, Melbourne, Australia. 

5 Department of Physical Activity and Rehabilitation Sciences, University of Liege, Belgium

6 Department of Physical Medicine, Rehabilitation and Sports Traumatology, SportS², FIFA Medical Centre of Excellence, FIMS Collaborative Centre of Sports Medicine, CHU de Liège, Liège, Belgique

7Luxembourg Institute of Research in Orthopedics, Sports Medicine and Science, Luxembourg

8Clinique du sport, Centre Hospitalier de Luxembourg, Luxembourg

9Division of Orthopaedic Surgery, Oslo University Hospital, Oslo, Norway.

10Oslo Sports Trauma Research Centre (OSTRC), Norwegian School of Sport Sciences, Oslo, Norway.

11Institute of Clinical Medicine, University of Oslo, Oslo, Norway.

12Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway.

13Department of orthopaedic surgery and traumatology, Geneva University Hospitals, Geneva, Switzerland

Correspondence to:

Tooth Camille, PT, PhD, Department of Physical Medicine, Rehabilitation and Sports Traumatology, SportS², FIFA Medical Centre of Excellence, FIMS Collaborative Centre of Sports Medicine, CHU de Liège, Avenue de l’Hôpital 1, 4000 Liège, Belgium. Tel: +32 495363755; E-mail: ctooth@uliege.be 

Funding: This work has been financially supported by the International Olympic Committee Medical and Scientific Commission programme for Prevention of injury and protection of athlete health (IOC Research Centres).

Competing Interest: Nothing to declare

Ethics approval: Not applicable

Data availability statement: Not applicable

Contributors: LdG wrote the synthesis, in collaboration with CT, FD, PT and RS. CA, GE, HM and HG reviewed the synthesis and the infographic and gave pertinent comments that improved the quality of this work. All authors understand that they are accountable for all aspects of the work and ensure the accuracy or integrity of this manuscript. 

Acknowledgements: The authors thank all authors of the “2018 International Olympic consensus statement on prevention, diagnosis and management of paediatric anterior cruciate ligament (ACL) injuries.”