Medial Collateral Ligament (MCL) Injuries

What is a medial collateral ligament (MCL) sprain? 

The medial collateral ligament (MCL) is the knee ligament on the inner part of your knee. It is one of the four major knee ligaments that help stabilize the knee joint. An injury is caused when the a force is too great for the ligament to resist, thus causing an overstretch of the MCL. This can be caused by sudden movements such as a sharp change in direction, twisting the knee while the foot is planted on the ground, or a blunt force to the knee. 

Injury severity?
Grade I

The knee ligament has a slight stretch, but it doesn’t actually tear. Although the knee joint may not hurt or swell very much, a grade I sprain can increase the risk of a repeat injury. Resting from painful activity and icing the injury can be useful to subside the pain.  

Grade II

The knee ligament tears partially. Swelling and bruising around the injury site are common, and use of the knee joint is usually painful and difficult. Use of a weight-bearing brace, or supportive taping are common treatments of this sprain. A physiotherapist may also help by providing strengthening and joint exercises to guide the healing process. 

Grade III

The knee ligament fully tears. Swelling and bleeding can sometimes be present under the skin. The joint is unstable and it can be difficult to bear weight. You can also feel the knee giving way. With a grade III sprain, surrounding structures, such as the meniscus and/or ACL also become at risk of injury. A grade III sprain should be rehabilitated under the guidance of a physiotherapist and/or knee specialist. 


  • Improve patellofemoral alignment 
  • Improve your proprioception, agility and balance
  • Improve your walking, running, and squatting techniques 
  • Strengthen your knee, especially quadriceps and hamstrings

If you have any pain during exercises, or are unsure about what you are doing, please consult your local physiotherapist before continuing.

Healthwise Staff (2017). Medial collateral ligament injury.
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