Medial collateral ligament (MCL) injury

Medial collateral ligament (MCL) injury

The medial collateral ligament (MCL) is a ligament that stabilises the knee. It is located on the inside of the knee. It is a commonly injured ligament and is often injured in combination with the ACL ligament and medial meniscus. When all three are injured it is called the unhappy triad knee injury.

A tear in the MCL ligament is also known as an MCL strain. There are three grades of MCL strains with grade three being a complete tear or rupture.


The MCL is injured through contact and non-contact forces. A contact injury is common in sports. This occurs when there is an impact to the outside of the knee. When this happens the knee is stress on the inside. If there is enough force, this will result in the ligament stretching and tearing. Non-contact injuries can also occur. These can result from falls such as those in downhill skiing, or in sports competition where there are large forces going through the knee. Just as in contact injuries, the MCL ligament are stressed on the inside of the knee and the over stretching and tearing results.


There are three grades of MCL ligament injury. The symptoms will depend on which grade of injury has occurred.

  • Grade 1 – some pain on the inside of the knee but generally no swelling. There is no instability of the knee.
  • Grade 2 – Much pain on the inside of the knee with some swelling. There will be some instability of the knee.
  • Grade 3 – Much pain on the inside of the knee with large swelling. Gross instability of the knee will be found.


The treatment for an MCL injury will depend on the above grade. However most treatment will require the use of a hinged brace to allow healing of the MCL and a comprehensive rehabilitation program. A sports chiropractor or physiotherapist can assist with the individualised rehabilitation program.

There is generally no difference in the outcomes of surgical and non-surgical management of MCL tears. Thus, non-surgical (bracing and exercises) is recommended first.

For more information please contact Sydney Spine & Sports Centre (S3C).