Tears and injuries of the anterior cruciate ligament (ACL) in the knee are epidemic in youth sports. Studies have shown that the rate of ACL injuries is increasing as sports participation increases. About a third of preteen and teen soccer players will sustain an ACL tear.

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Related post: Treating ACL tears in youth athletes

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When teen athletes have a knee injury that has associated swelling, up to two-thirds of them will have an ACL tear. Girls are more than twice as likely to have an ACL injury than boys.

What is the ACL?

ACL stands for anterior cruciate ligament:

• Anterior means that it attaches in the front part of the knee on the front part of the shin bone.
• Cruciate means that it's a crossing-type ligament — it crosses the knee.
• Ligament is a type of tissue that holds a joint together or connects bone to bone.

The ACL stabilizes the knee during front-to-back motions and rotation. It is deep inside the knee so it’s difficult for you or your athlete to feel it and know if the ACL was torn.

An ACL tear isn’t noticeable during most day-to-day activities like walking or climbing stairs. Instead, your child will feel it when they do twisting motions such as playing sports or getting in and out of a car.

Causes of ACL tears in young athletes

The most common way that young people tear their ACLs is actually through non-contact injuries — when an athlete moves in one direction to chase after that ball, then suddenly twists and changes direction. Sports where this is more likely include:

• Soccer
• Tennis
• Volleyball
• Football
• Skiing

After the pivoting-related injury, the youth athlete may feel like their knee is weak but be able to walk off the field. Parents should be on the lookout for swelling and dull, achy pain following the injury to know if they should see an orthopaedic specialist.

Diagnosing an ACL tear in young players

The first step to diagnosing an ACL tear is getting an X-ray. This noninvasive test provides important information, including:

• Whether there are broken bones that could be causing a swollen knee
• Whether your child is still growing
• A picture of how the hips, knees and ankles line up over each other, which may identify an anatomical reason for why the injury happened and give information about how to modify and prevent future injury

The limitation of X-rays is they don't show the soft tissues like ligaments or cartilage. To assess those structures, magnetic resonance imaging (MRI) is needed. MRI offers a look at the ACL and the cartilage on the outside of the bones.

The MRI also offers a view of the growth plates so your child’s doctor has an idea of how much more growing your child has to do. This can inform which nonoperative and operative treatment options are appropriate.

Managing an ACL injury in young athletes

Before your child can undergo treatment, their knee needs to be free of swelling and ready for treatment. These steps are critical:

• Movement: Your child may not feel like moving their hurt knee, but motion is important to keep fluid from building up. Move the knee in circular and up or down motions. Avoid weight-bearing activity.
• Icing: Make sure you have several ice packs: one cold in the freezer while another is on your child’s knee. Put ice packs on both the front and back of the knee (a bandage can be used to hold the ice pack in place). Keep the ice in place for 15 to 20 minutes and repeat every one to two hours.

Preventing ACL injuries in youth athletes

Prevention programs are effective at decreasing ACL injuries by focusing on:

• Strengthening: Core, hip and thigh strengthening
• Technique: Maintaining proper technique when jumping, landing and cutting to change direction
• Balance: Practicing one-legged balance to protect the knee
• Stamina: Avoiding activity when they are fatigued because they put their knees in more dangerous positions
• Recovery: Giving the body breaks when possible, which can be difficult for year-round athletes

UCLA Health specialists at the Center for Sports Medicine help young athletes recover from sport injuries like ACL tears.

Learn more about our state-of-the-art pediatric orthopaedic care through our partnership with Orthopaedic Institute for Children.

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Tags: ACL injury in young athletes, ACL tear, diagnosing ACL tears, Healthy Living, injuries in athletes, News & Insights, Orthopaedic Institute for Children, Orthopaedic Surgery, pediatric orthopaedic care, pediatrics, Pediatrics, UCLA Center for Sports Medicine