Anterior Cruciate Injuries in Children and Teenagers
Over the last two decades the number of ACL injuries amongst children and adolescents has increased by 2.3% per year. The ACL is an important ligament, and provides stability to the knee in situations which involve rotation and hyper-extension. The stability provides protects the meniscus and joint surfaces. Any damage to a meniscus in the knee can increase joint contact stresses by up to 500% and in many cases can be a predisposing factor for osteoarthritis later in life. Osteoarthritic changes are often seen at 10 years post injury.
Historically a young athlete with an ACL injury was treated with a brace and activity modification until skeletal maturity, with ACL reconstruction (using a graft) being performed at the time in those who experienced giving way. More recently however evidence has shown that delayed reconstruction may lead to increased damage to the meniscus and joint surfaces. As a result, early reconstruction is often favoured in the active person, to protect the meniscus and allow continued physical activity. These injuries in skeletally immature patients present a challenge as the techniques used for adult reconstruction, have potential to upset the growth plates in children. As a result different surgical techniques are used in young people.
According to a recent report, 96% of young patients return to sport at the same level following ACL reconstruction. The risk of graft injury (meaning injury to the surgically placed graft) is much higher in young patients with the biggest risk coming in those 10 to 19 years. On review suggested 29.5% of young athletes sustained second ACL injury within the first year is returning to sport. Furthermore, a recent review has suggested that the risk of an ACL tear in the opposite leg is common in those who have sustained an ACL injury and probably even is greater than a graft injury.
Prevention
Well-designed exercise programs may reduce the risk of both ACL injuries and graft injuries. There are four key factors to consider when developing an ACL prevention program:
Age at which to start the intervention
Dosage to be prescribed
Exercises to be included
Feedback is given to the athlete
Importantly a multitude of exercises need to be incorporated into the program, and although we don’t know the optimal amount of exercise, greater than 20 minutes, several times per week seems to be more effective than lesser amounts.
Rehabilitation
Following ACL reconstruction adequate rehabilitation is considered vital. Considering the re-injury risk to the reconstructed knee and the high risk to the other knee, a preventative program is a key component of this. It can be difficult to get younger children to follow directions, and risk-taking behaviour in teenagers is commonplace. Rehab needs to be guided by a Physiotherapist. Access to equipment for resistance training is important. Home or on-field programs can be adequate in respectively the early and late stage of rehabilitation but often lack the scope to provide adequate rehabilitation.