Key Points about Medial Collateral Ligament (MCL) Injury

  • MCL injuries occur when a ligament on the inner side of the knee becomes stretched or torn, often from a direct hit to that side of the knee.
  • Symptoms of an MCL injury include pain and swelling along the knee’s inner edge.
  • Treatment for an MCL injury involves resting the affected leg, icing the injured area, and avoiding activities that cause pain.
  • Surgery is rarely required to treat an MCL injury.
Common related conditions
Anterior Cruciate Ligament (ACL) Injury Knee Dislocation Meniscus Tear or Strain Thigh or Calf Strain or Sprain


The medial collateral ligament, or MCL, is an important ligament in the knee that prevents the knee from bending in the wrong direction. When this ligament, located along the inner side of the knee, is hit or twisted, an MCL injury can result. MCL injuries often result from a direct hit during a contact sport such as football.

MCL injuries usually resolve on their own, without medical treatment, after a few weeks or months. After an MCL injury you should rest the affected leg, ice the injured area, and avoid activities that cause pain. Your doctor may also advise you to take over-the-counter anti-inflammatories to manage pain and swelling, and to follow a specific physical therapy and rehabilitation regimen.

Call your doctor if you have pain and swelling in the knee following an injury, or if you heard a “pop” at the time of the event. 

MCL injury causes

MCL injuries usually occurs after a direct hit or trauma to the medial collateral ligament of the knee, which is located along the knee’s inner edge. An MCL injury can also result from a knee movement that causes the ligament to stretch or overextend.

MCL injury risk factors

You may be at an increased risk of experiencing an MCL injury if you play a contact sport such as ice hockey or football.

MCL injury symptoms

Signs and symptoms of an MCL injury include:

  • Hearing a “pop” noise at the time of the injury
  • Pain and swelling on the knee’s inner edge
  • The knee bending to the side at the time of the injury

MCL injury diagnosis

When diagnosing a possible MCL injury, your doctor will examine the affected knee and will ask you about your symptoms.

In some cases, your doctor may order imaging tests such as an MRI scan or X-ray to assess the degree of damage or rule out other injuries.

MCL injury treatment

MCL injuries tend to heal on their own without medical intervention within up to a few months. Your doctor will likely recommend resting and icing the affected knee. Your doctor may also recommend taking over-the-counter anti-inflammatories or provide you with a physical therapy regimen.

Surgery is rarely required to treat an MCL injury, unless other ligaments in the knee are damaged as well.

When to seek care

Call your doctor if you have severe knee pain, swelling, and an inability to walk following an injury to the knee.

Next Steps

Your doctor will assess your MCL injury and set up a treatment plan accordingly.

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