What is the ACL?

ACL stands for anterior cruciate ligament – one of 2 ligaments inside the knee joint. Its purpose is to stop the tibia (shin bone) from moving forward on the femur (thigh bone) and it also helps externally rotate (twist) the tibia at full extension, prevents hyperextension of the knee and plays a part in neurosensory control.

Do ACL tears occur in young athletes?

ACL tears are uncommon in pre-pubertal children but there has been a recent increase in injury rates in children and adolescents, particularly in the 10 – 14 year old age. This may be due to increased participation in intense sport at an earlier age, earlier sports specialization or improved detection due to MRI.

Who is at most risk of an ACL tear?

Girls have a 2-3 times higher risk than boys (taking into account exposure) and girls also get tears at a younger age (teenage years in girls v early 20’s in boys). The most common sports are netball, basketball, soccer, rugby union, rugby league and skiing.

How does the ACL get injured?

70% of ACL tears are non-contact injuries – there is a twisting or deceleration injury, often when the athlete tries to change direction when running and they may report hearing a pop or feeling a popping sensation. The other 30% are traumatic injuries occurring during contact or trauma.

How do I know if the ACL is injured?

There is usually a large amount of swelling in the knee joint within 1-2 hours of an ACL injury. An experienced physiotherapist or doctor can detect an ACL injury with an examination on the field at the time of the injury but as soon as 10 minutes after the injury there may be too much swelling for an accurate examination.

Due to the immature skeleton, children may sustain different knee injuries to adults – a tibial eminence fracture presents the same way as an ACL tear, therefore x-rays are needed after every acute knee injury in a child. Tibial spine avulsions (some bone pulling off with the ligament at its attachment) are much less common than mid ligament tears but can occur in younger children.

A treating doctor may like to perform an MRI to confirm the diagnosis of ACL injury and rule out other soft tissue injuries to the cartilage surfaces or the meniscus but this isn’t always necessary.

Can an ACL injury be prevented?

Injury prevention programs should be implemented early in a child’s athletic career to develop strong and favorable movement patterns. Programs like the FIFA 11+ for kids can be used as a warm up program at training and games for many sports and these programs have been proven to reduce the risk of ACL injury.

Unfortunately there are some factors for ACL injury that can’t be modified including gender and genetics. The biggest risk factor for having an ACL tear is having already had one in the past.

How is an ACL injury treated in a child or adolescent?

Estimating skeletal age and remaining growth are important considerations for making decisions about treatment.

Goals of treatment of a child or adolescent with an ACL injury are to restore a stable, well functioning knee to enable a healthy, active lifestyle, to reduce the risk of further joint injury and to minimize the risk of growth arrest and deformity of the long bones of the leg.

The two treatment options are high quality rehabilitation alone (non-surgical treatment) and ACL reconstruction (surgery) plus high quality rehabilitation.

The decision between surgical and non-surgical management isn’t straightforward and is made on an individual basis, after a thorough consultation taking into account all the factors relating to the injured young athlete and their circumstances.

Non-surgical treatment should be guided by an experienced physiotherapist and last for 3-6 months before returning to sport.

Post operative rehab should last at least 9 months but the risk of a second ACL injury following an ACL reconstruction is the highest in the first 12 months after surgery, therefore it’s best for the child or adolescent not to return to pivoting sports until at least 12 months after surgery.

If you or your child has sustained a knee injury that has resulted in significant joint swelling, pain or a limp, a consultation at Shire Sports Medicine can be beneficial for you to get an accurate diagnosis, to help guide management of your injury and to ensure the prevention of further complications.