The medial collateral ligament (MCL) is a thickened band-like structure on the inside of the knee that attaches to the bottom of the thigh bone (femur) and crosses the knee joint where it attaches to the top of the shin bone (tibia). It is one of the four main ligaments responsible for maintaining the stability of the knee joint and functions to resist force applied from the outer surface.

MCL injuries are classified based on their severity into 3 grades: Grade 1 (mild), Grade 2 (moderate) and Grade 3 (complete tear). Often higher grade MCL injuries will occur in combination with injury to other structures in the knee joint such as the medial meniscus or anterior cruciate ligament (ACL).


An injury to the MCL can be caused by:

  • A sudden force to the outside of the knee while it is slightly bent e.g. a heavy tackle in rugby
  • A twisting force to the knee while the knee is slightly bent

What do I feel?

  • Pain and tenderness over the inside aspect of the knee
  • A popping or tearing may be felt or heard at the time of injury in some cases
  • Localised swelling may be present
  • Some instability may be present in the knee

What can I do?

  • Apply ice to the knee for pain relief for 20mins every 2hrs for the first 48-72hrs
  • Elevation – prop the leg up on pillows
  • Rest from activity
  • Apply compression to the knee joint area
  • Take pain relief medication as directed on the label or by your doctor/pharmacist
  • See a physiotherapist for effective rehabilitation and exercises

Due to the varying grades of MCL injury, it is very important to get comprehensive assessment and treatment from a physiotherapist. Isolated mild-moderate MCL injuries are managed conservatively with physiotherapy and may take 4-6 weeks to return to full function. For more severe MCL injuries, return to higher-level activity may take 10-12 weeks of rehabilitation.

Physiotherapy management consists mainly of bracing, swelling management, restoring range of movement, progressively strengthening the muscles surrounding the knee joint and maintaining balance/coordination. Early use of reduced weight-bearing exercises such as hydrotherapy and/or cycling on a stationary bike is recommended.

In rare cases, surgical intervention may be required when the injury involves multiple ligaments/structures within the knee joint. After surgery, physiotherapy management similar to low-grade MCL injuries is essential for rehabilitation. Your physiotherapist will guide you in a graduated return to play program once the injury has healed correctly.