Health Information For Parents

Medial Collateral Ligament (MCL) Injuries


What Are Medial Collateral Ligament (MCL) Injuries?

A torn medial collateral ligament (MCL) is a serious knee injury, especially for kids who play sports. Ligaments are long, rope-like bands that fasten bones together. The MCL helps keep the knee stable.

Most kids and teens with an MCL injury will still need to undergo rehabilitation (rehab) therapy to help regain strength in the joint.

How Do Medial Collateral Ligament Injuries Happen?

Most kids who get a torn MCL play contact sports, like football and soccer. More severe injuries happen when the outside of the knee is struck, causing it to unnaturally bend inward (toward the other knee).

MCL tears can also happen when the lower leg twists or bends out too far. This creates tension on the medial collateral ligament, a rope-like band, and it stretches or breaks in half.

What Does the MCL Do?

The medial collateral ligament is one of the four main ligaments in the knee joint. It’s on the side of the knee that’s close to the other knee. One end of the ligament is attached to the femur, while the other end is attached to the tibia.

With the lateral collateral ligament (LCL), which is in the same location on the outside of the knee, the MCL helps prevent the knee joint from bending too far from side-to-side.

What Are the Signs & Symptoms of a Torn MCL?

Someone with a partially or completely torn MCL may not have symptoms, depending on the severity of the injury. But a torn MCl can:

  • cause swelling and pain in the first 24 hours of injury. This can be intense initially.
  • cause some instability when walking, feeling “wobbly”
  • make it hard to put weight on the affected leg

Many kids and teens, especially those who are familiar with the injury or have torn a ligament before, report hearing a “pop” sound. This is the sound of the shinbone popping out of and back into the knee joint.

Diagram shows left knee bent from right side and labels torn MCL, thighbone, and shinbone

A child who has injured a knee — whether on the field or at home — should stop all activity, to prevent further injury, and get medical care right away.

In the meantime, keep the area iced. Put the ice in a plastic bag, wrap the bag in a cloth, and hold it to the knee for 20 minutes at a time. Also, keep the knee elevated as much as possible to reduce swelling. As long as walking isn’t painful, it’s OK to walk with an MCL tear. But if standing or walking causes any pain, don’t let your child put weight on the knee.

How Is a Torn MCL Diagnosed?

At the doctor’s office or emergency room, doctors will do an exam and order imaging tests to see if there’s a knee injury and, if so, how severe it is.

To help diagnose an MCL injury, doctors do a Valgus test. The person lies down flat, and the doctor moves the affected leg out to the side while flexing the knee about 30 degrees. The doctor places one hand on the back of the knee joint and the other on the top side of the ankle. The doctor then rotates the shin bone and pushes the foot outward, to see how far the MCL will extend. Too much flexibility can signal an injury.

To properly diagnose MCL injuries, doctors usually do these tests in combination or along with other physical exams.

While X-rays might be taken to find the extent of the injury, they only look at bone and can only confirm that there are bone fractures in the knee. An MRI looks at tissue (like ligaments and muscles), and can confirm a partial or complete MCL tear, so some doctors will order one to confirm a diagnosis.

Types of MCL Tears

Doctors categorize MCL injuries according to these criteria:

  • Grade I tear. This is a slight tear (or stretch) of the MCL. Both ends of the ligament are still attached to the bone, but part of the ligament may sag and be less tight. Recovery usually takes 1 to 2 weeks; therapy may not be needed.
  • Grade II tear. This is a slightly more severe tear of the MCL, with part of the ligament sagging. Pain and swelling is usually more severe than with a grade I tear. People usually need 3 to 4 weeks of rest and sometimes therapy.
  • Grade III tear. With this type of injury, the MCL breaks in half. Many people are unable to bend the knee or put weight on it without pain. They may be unstable while walking, and the knee may sometimes “give out.” Doctors may recommend a temporary knee brace for people with this injury as well as rehab therapy for 6 weeks or longer.

How Is an MCL Injury Treated?

Treating MCL injuries requires initial resting of the joint with ice, elevation, and elastic compression bandages to help ease discomfort, pain, and swelling. It’s OK to put weight on the knee as long as it’s not painful.

Depending on the severity of the injury, doctors may recommend crutches, limiting physical activity, and a temporary knee brace. Putting too much pressure on the knee can cause reinjury. Over-the-counter or prescription painkillers and anti-inflammatory medicine can help kids deal with the pain and feel more comfortable.

Doctors usually recommend rehab therapy to help heal the knee and to:

  • restore range of motion
  • regain strength in the knee, thigh, and shin muscles
  • prevent atrophy (the breakdown of muscle tissue)
  • reduce pain and swelling
  • improve balance

Most kids and teens do rehab at a center three times a week, with daily exercises they practice at home. Some do accelerated rehab programs with more frequent therapy sessions, but recovery may not be any faster.

Most sports are off limits, especially the activity that caused the injury. Ask your child’s doctor about low-impact activities like swimming, bike riding, or protected running.

How Can Parents Help?

Being told that you can’t do the things you love — like running or playing football, field hockey, or softball — can be hard for any child. Kids and teens recovering from an MCL injury, especially a severe one, may feel angry, frustrated, and even depressed, especially if they’re no longer participating in team sports with their friends.

But there are ways to still feel like part of the team. Keeping score, being a coach’s assistant, or bringing water to the games may help. If your son or daughter doesn’t want to do these things, suggest starting a hobby, like playing the guitar, painting, drawing, or another activity that won’t put too much strain on the knee. Low-impact activities, like swimming, are another option.

In time, kids and teens can again do the things they love. Kids who feel angry or depressed during recovery might benefit from talking to a school psychologist or counselor, who can help them cope and look ahead to better days.

Medical Review

  • Last Reviewed: October 14th, 2015
  • Reviewed By: Rupal Christine Gupta, MD



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