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Medial Collateral Ligament Injuries

The medial collateral ligament (MCL) is one of the four major ligaments that stabilize the knee.  Located along the inside of the knee, it connects the thigh bone (femur) to the shin bone (tibia) and normally prevents them from separating.

Ligament injuries such as MCL’s are called “sprains.” An MCL injury  (stretching and/or tearing) typically occurs when stress is put on the ligament through one of two ways: a blow to the outside of the knee, or an inward twisting of the knee with the foot planted.  An MCL injury may occur by itself or with other knee injuries.


The most common symptom of an MCL injury is pain over the inside of the knee. People with more severe MCL injuries may have swelling or bruising one to two days after the injury. Patients with a complete MCL tear may feel like their knee is unstable or that their knee is “giving out.”


Your child’s doctor can diagnose the injury with a physical exam that includes special knee tests. They may perform additional tests such as x-rays and magnetic resonance imaging (MRI)to search for other injuries and to confirm the MCL injury. 

MCL injuries are graded as follows: 

  • Grade I: The MCL is stretched but not torn
  • Grade II: The MCL is partially torn but some fibers are still intact
  • Grade III: All of the MCL fibers are completely torn


Most MCL injuries heal without surgery, using rest and physical therapy to regain strength and agility. Doctors often prescribe a hinged knee brace to protect the MCL during the healing phase. For a grade III injury, your physician may recommend using crutches as well.  Grade III MCL injuries rarely require surgical correction.

Returning to Activities & Sports

We want to return your child to their sport as quickly and safely as possible.  If your child returns to sports or activities too soon or pushes through pain, the injury may worsen, which could delay healing or cause further damage.

Your child may return safely to sports or activities when your physician or physical therapist confirms your child’s knee and leg have regained normal strength and their inner knee isn’t tender. Your child should also be able to do the following before returning to sports:

  • Jog straight ahead without limping
  • Sprint straight ahead without limping
  • Run 45 degree cuts
  • Run 90 degree cuts
  • Run 20 yard figure-eights
  • Run 10 yard figure-eights

Make an Appointment

If you’d like to request an appointment with one of our Institute for Sports Medicine specialists, call 1.800.543.7362 (1.800.KIDS DOC®). You can also request an appointment online.