MCL Injuries

What is an MCL injury?

MCL injuries are damage to the medial collateral ligament (MCL) in the knee. The MCL is one of four major ligaments that keep the knee from wobbling when you move.

  • To understand MCL injuries, it helps to know a little about how the knee works.

    The knee is a large joint where the shinbone (tibia) meets the thighbone (femur).

    Two ligaments – the posterior cruciate ligament (PCL) and the anterior cruciate ligament (ACL) – cross each other in the middle of the knee. They work together to keep the shinbone attached to the thighbone.

    Two other ligaments run along either side of the knee:

    • The lateral collateral ligament (LCL) runs along the outside and keeps the knee from bending out.
    • The MCL is on the inside and keeps the knee from bending in.
  • When the knee suddenly bends inward with the foot bent outward, the MCL and other ligaments can tear, either partially or all the way. These kinds of injuries can occur during collisions in football and soccer and during car accidents.

    MCL injuries also sometimes happen in combination with ACL tears.

  • MCL tears, while common in adults, are less common for children. But teenage athletes are more likely to injure their MCL than other teenagers. This is especially true if they play sports that put them at risk of colliding with other players from the side, such as football and ice hockey.

    Older children are more likely to injure their MCL than children who are younger than age 12. Younger children more often break the bone where the ligament attaches.

MCL Injuries at Seattle Children’s

Seattle Children’s treats the full range of bone, muscle and joint conditions, including MCL, PCL and ACL injuries.

    • Your child is cared for by an orthopedics team, including pediatricians, pediatric orthopedic surgeons, nurse practitioners, physician assistants, nurses and physical therapists.
    • To restore your child’s health and function, we use nonsurgical methods, like physical therapy (PT), including sports PT, whenever possible. We have the largest team of physical therapists in the Pacific Northwest who specialize in the care of babies, children, teens and young adults.
    • Children and teens rarely need surgery for MCL injuries. If your child does need surgery, we have pediatric orthopedic surgeons with expanded fellowship training in sports medicine and the experience to repair knee ligaments.
    • A child’s knee injury is more difficult to treat than an adult’s. This is because doctors must avoid injury to the growth plates on children’s bones above and below the knee. Here, your child’s team has special training in the medical and surgical needs of young people.
    • We have the largest group of board-certified pediatric radiologists in the Northwest. If your child needs imaging that uses radiation, we use the lowest amount possible (PDF) to produce the best image.
    • Athletic trainers from our Sports Medicine Program work at dozens of area schools, teaching conditioning, assessing and treating injuries and referring athletes to medical providers, all with an eye to keeping your child active for years to come.
    • Your child may be more likely to need surgery if they injured their ACL along with their MCL. We are careful to determine whether your child needs surgery.
    • Our surgical methods limit the risks of injury to growth plates. This increases the chances that your child will be able to return to sports.
    • Our rehabilitation programs are designed so that your child will recover range of motion, rebuild strength and stability, restore balance and regain confidence in using their knee.
    • To help your child return to play quickly and safely, we do more than treat their current injury. We focus on preventing repeat or new injuries.
    • For your convenience, our doctors see patients at several locations around Washington. Seattle Children’s sports physical therapy is available in Seattle, Bellevue, Everett and Federal Way to make ongoing rehab easier for you.

Symptoms of MCL Injuries

If your child’s knee suddenly swells after an accident or injury, they may have a torn MCL or another serious knee problem. Other signs of an MCL injury include:

  • Knee is unstable.
  • Knee hurts, with pain along the inside of the knee.

Diagnosing MCL Injuries

MCL testing. Courtesy of

MCL stability testing.

To help protect your child from more injuries that could hurt growing bones and joints, it is important to get a thorough evaluation and proper treatment early on. When injuries are discovered and treated early, children rarely need to have surgery to reconstruct their MCL.

  • When you and your child come to our clinic, we:

    • Ask what happened before the knee began to swell and hurt.
    • Examine your child’s knee. To doctors trained in sports medicine, knees with MCL tears often feel loose.
  • We cannot be sure that your child has a torn MCL until the swelling in the knee has gone down. This usually takes 7 to 10 days. At that time, we will likely take radiographs of your child’s knee to help find out what is wrong.

    If it is not clear that the MCL is torn or if we think your child may have other injuries, we may ask your child to have an MRI (magnetic resonance imaging) scan of the knee.

Treating MCL Injuries

We emphasize treating mild MCL injuries through rehabilitation therapy whenever possible.

Most children who have an MCL injury and no other injury to the knee do well after wearing a hinged knee brace for 3 to 4 weeks and participating in a rehabilitation program.

Surgery is rarely needed.

  • At Seattle Children’s, we provide a regular course of PT, including sports PT, designed especially for your child. Our aim is for your child to:

    • Recover range of motion.
    • Rebuild strength and stability.
    • Restore balance.
    • Regain confidence in using the knee.

    These services are available at our dedicated sports gym.

  • A child who has both an MCL injury and an ACL injury probably will need surgery to reconstruct the ACL. Doctors usually do the surgery once your child can move the knee again. Learn more about ACL injuries and treatment.

Contact Us

Contact Orthopedics and Sports Medicine at 206-987-2109 for an appointment, a second opinion or more information.

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