The number of anterior cruciate ligament injuries seen in children is on the rise. The SingHealth Duke-NUS Sport & Exercise Medicine Centre shares what to look out for in primary care.
With the increasing number of anterior cruciate ligament injuries seen in children, general practitioners have a crucial role to play in initial assessment and patient education to reduce and manage such occurrences. The SingHealth Duke-NUS Sport & Exercise Medicine Centre shares what to look out for in primary care, along with key takeaways regarding treatment options and preventive measures.
INTRODUCTION TO PAEDIATRIC ACL INJURIES
Anterior cruciate ligament (ACL) injuries have long been associated with adult athletes, but recent years have seen a rise in the occurrence of paediatric ACL injuries. This is due in part to the intensification of youth sports participation and specialised training at younger ages.
This trend has sparked concerns among parents, coaches and healthcare professionals alike.
This article aims to shed light on paediatric ACL injuries and their causes, treatment options and preventive measures.
CAUSES AND RISK FACTORS
These injuries often happen in sports that involve cutting, pivoting and sudden changes in direction, such as soccer, basketball, netball, gymnastics and skiing.
Studies show that ACL injuries account for about 30% of all knee injuries amongst soccer players aged between 5 and 18 years old.1 The incidence of ACL injuries in the preadolescent age group can be as high as 47% amongst those presenting with acute knee hemarthrosis.2
The causes of paediatric ACL injuries are attributed to a combination of biomechanical, anatomical and hormonal factors. The rapid growth during puberty can result in imbalances between muscle strength and joint stability, making the ACL more vulnerable to injury.
1. Biomechanical factors
Children often exhibit landing and cutting techniques that place excessive strain on the knee joint. Incorrect landing from a jump, sudden direction changes and pivoting motions can contribute to ACL injuries.
Poor neuromuscular control, balance and muscle coordination will further increase the risk.
2. Anatomical factors
Differences in bone and joint development between children and adults can impact the risk of ACL injuries.
Paediatric ACL injuries are more likely to involve an avulsion fracture. This is due to the relative weakness of the immature bones in comparison to the strength of the developing ligaments.
On the other hand, a mid-substance ACL tear can occur in higher-energy pivoting injuries.
3. Hormonal factors
Hormonal changes during puberty, such as oestrogen fluctuations, might play a role in ligament laxity, potentially increasing the risk of ACL injuries.
However, further research is needed to establish a direct link between hormonal changes and ACL injury risk.
When a paediatric ACL injury occurs, prompt and appropriate treatment is crucial to ensure successful recovery and prevent long-term complications.
Two treatment options can help the child with an ACL injury achieve these goals: high-quality rehabilitation alone (nonsurgical treatment), and ACL reconstruction plus high-quality rehabilitation.
1. High-quality rehabilitation alone
Paediatric rehabilitation must be performed in close collaboration with the child’s parents.
Exercises and functional goals must be modified from the adult-oriented rehabilitation protocols, because they cannot perform unsupervised training independently with good technique.
Qualified rehabilitation clinicians must supervise rehabilitation for the child with an ACL injury. It is also recommended that they wear a protective brace even during strenuous physical activities.3
2. Surgical intervention with postoperative high-quality rehabilitation
Consideration of the physis
The general principles of ACL reconstruction in adults apply to the paediatric patient with one major difference – that is, consideration of the physis.
While several ‘physeal-friendly’ techniques of ACL reconstruction exist, the risk of physeal disturbance, although low (2-10%), is ever-present.4 Physeal disturbances can arise from growth arrest, growth stimulation or undergrowth, leading to limb length discrepancies and angular deformities around the knee.
Current lack of evidence
To date, there is still no high-quality evidence with regard to the adaptation of the ACL reconstruction grafts and bone tunnels as the child grows.
There is also a lack of high-quality prospective studies investigating the outcomes of surgical and nonsurgical treatment for paediatric ACL tears.5
Timing of surgery
High-quality rehabilitation can be considered for an ACL-injured patient, with the option to delay reconstruction closer to skeletal maturity.
However, early surgery is advocated for patients with recurrent instability despite rehabilitation, with the aim of preventing concomitant meniscus and chondral injuries associated with multiple instability episodes.
There should be consensus among all parties when arriving at a treatment decision. This consensus should be based on realistic assessments of risks and benefits, and proper consideration of the goals of the child and parent.
ACL injury prevention is important since it helps to reduce the risk of a reinjury, and even injury to the contralateral knee. The paediatric athlete’s biomechanical movement patterns are a key modifiable risk factor for injury.
Preventing paediatric ACL injuries involves a combination of education, proper training techniques and injury prevention programmes.
1. Neuromuscular training
Incorporating neuromuscular training programmes can help improve landing and cutting techniques, enhance muscle coordination and reduce the risk of ACL injuries. These programmes focus on developing proper movement patterns and muscle activation strategies.
2. Strength and conditioning
A well-rounded strength and conditioning programme can help the young athlete develop balanced muscle strength, stability and flexibility, hence reducing the strain on the ACL during sports activities. FIFA 11+ Kids is an example of a well-established injury prevention programme for soccer players, which reduces football-related lower extremity injuries by over 50%.6
3. Warm-up and cool-down
Proper warm-up and cool-down routines are essential to prepare the body for physical activity and aid in recovery. Dynamic stretching before exercise can help improve joint mobility and reduce the risk of injury.
4. Education and awareness
Coaches, parents and athletes should be educated about the risks of ACL injuries and the importance of adhering to proper techniques and training guidelines.
The general practitioner (GP) plays an important role in the initial assessment of the paediatric patient with a suspected ACL injury.
In the history-taking, the mechanism of injury is usually a twisting injury to the knee from poor landing, sudden change in direction or an awkward tackle.
Look for signs of limited knee range of movement associated with a moderate-sized effusion due to hemarthrosis.
In the acute setting, the assessment of the ligaments may be difficult due to discomfort and swelling.
An MRI is very useful to evaluate any bony, cartilage and soft tissue abnormalities in the paediatric knee.
Paediatric ACL injuries are a growing concern in the realm of paediatric sports. While the causes of these injuries are multifactorial, understanding the biomechanical, anatomical and hormonal factors contributing to ACL injuries is essential.
Through a combination of conservative management, surgical intervention when necessary and preventive measures, the occurrence of paediatric ACL injuries can be reduced. By prioritising strength and conditioning, proper training techniques and education, we can ensure the safety and well-being of young athletes as they pursue their passion for sports.
Shea KG, Pfeiffer R, Wang JH, Curtin M, Apel PJ. Anterior cruciate ligament injury in pediatric and adolescent soccer players: An analysis of insurance data. J Pediatr Orthop 2004; 24(6): 623-8.
Stanitski CL, Harvell JC, Fu F. Observations on acute knee hemarthrosis in children and adolescents. J Pediatr Orthop 1993; 13(4): 506-10.
Moksnes H, Engebretsen L, Seil R. The ESSKA paediatric anterior cruciate ligament monitoring initiative. Knee Surg Sports Traumatol Arthrosc. 2016;24:680-687.
Frosch KH, Stengel D, Brodhun T, et al. Outcomes and risks of operative treatment of rupture of the anterior cruciate ligament in children and adolescents. Arthroscopy. 2010;26:1539-1550.
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.
Moksnes H, Engebretsen L, Risberg MA. The current evidence for treatment of ACL injuries in children is low: a systematic review. JBone Joint Surg Am. 2012;94:1112-1119.
Dr Mohammad Ashik bin Zainuddin is the Head and Senior Consultant at the Department of Orthopaedic Surgery in KK Women’s and Children’s Hospital (KKH). He concurrently holds the appointment of Head of Service for the Singapore Sport and Exercise Medicine Centre (SSMC) at KKH. He received his fellowship training in sports traumatology and paediatric orthopaedics in Germany and Austria. His clinical and research interests are in the fields of arthroscopy, paediatric anterior cruciate ligament, sports medicine and cartilage preservation.
GPs can call the SingHealth Duke-NUS Sport & Exercise Medicine Centre for appointments at the following hotlines or click here to visit the website:
Singapore General Hospital: 6326 6060
Changi General Hospital: 6788 3003
Sengkang General Hospital: 6930 6000
KK Women's and Children's Hospital: 6692 2984