An MCL injury is a sprain or tear of the ligament on the INSIDE of your knee.
Let’s start with the good news: most MCL injuries heal WITHOUT surgery, because this ligament has a good blood supply.
Typical healing times with treatment:
- Grade 1 (stretched): about 1 to 3 weeks
- Grade 2 (partly torn): about 4 to 6 weeks
- Grade 3 (fully torn): 6 weeks or more
Surgery is mainly considered when other structures in the knee, such as the ACL, are torn too.
What the MCL does and how it gets hurt
The medial collateral ligament (MCL) runs down the inner side of the knee, from the thighbone to the shinbone. It stops the knee from bending inward. It is the most commonly injured ligament in the knee.
- A blow to the outside of the knee, such as a tackle in football or rugby, pushing the knee inward
- A twist with the foot planted, common in skiing, soccer and basketball
- A slip or awkward landing in everyday life
Symptoms
- Pain and tenderness along the inner side of the knee
- Swelling, usually on the inner side rather than the whole knee
- Stiffness and difficulty fully straightening or bending
- A wobbly feeling when you twist or cut, more likely with a grade 2 or 3 tear
Oddly, a complete (grade 3) tear can hurt LESS than a partial one, because the torn fibers are no longer being stretched. Pain level alone doesn’t tell you the grade.
The three grades
- Grade 1: the ligament is stretched but not torn. The knee is sore but stable
- Grade 2: some of the fibers are torn. The knee opens a little when pushed inward, but the ligament still holds
- Grade 3: the ligament is completely torn. The knee opens noticeably, and other injuries are more likely
A doctor or physio grades it by gently pushing the knee inward and feeling how much it opens. An MRI is sometimes used to check for ACL or meniscus damage. See meniscus tear.
The MCL is one of the few knee ligaments that heals well on its own. Your job is to protect it while it does, and keep the knee moving.
Do you need a brace?
- Grade 1: usually not. Some people like a light support for comfort
- Grade 2 and 3: a hinged knee brace is common. It stops the knee from bending inward but still lets it bend and straighten, so it doesn’t stiffen up
- How long: often a few weeks for grade 2 and around 6 weeks for grade 3. Your doctor will set the timeline
- Coming off it: wean it gradually, for example leaving it off at home first and wearing it in crowded places or on uneven ground
Recovery: what to do week by week
- First few days: ice, elevation and walking as comfort allows. Crutches if you are limping badly. Start bending and straightening the knee gently
- Weeks 1 to 3: regain full straightening and bend. Tighten the thigh muscle, do straight leg raises and use a stationary bike
- Weeks 3 to 6: build strength with squats, step-ups and bridges. Add balance work on one leg
- Return to sport: once the knee is pain-free, stable when tested, and you can run, hop and change direction without pain. Grade 1 can be back in about 2 weeks; grade 3 takes longer
- Avoid for now: twisting on a bent knee and breaststroke kick, which both stress the inner knee
Some aching and swelling on the inner knee can linger for a few months after you are back to normal activity. That is common and usually settles.
When is MCL surgery needed?
- Combined injuries: most often an MCL tear with an ACL tear. The MCL is often given time to heal first, and the ACL is reconstructed later. See ACL reconstruction recovery
- Certain grade 3 tears: for example where the ligament has pulled off the shinbone and flipped out of position, so it can’t heal in place
- Ongoing instability: the knee still opens and gives way after a proper period of bracing and rehab
For a clear explanation of grades and treatment, see the Cleveland Clinic’s guide to MCL tears.
Get it checked soon if
- You heard a pop and the whole knee swelled within a few hours. That can mean an ACL tear
- You can’t put weight on the leg or the knee looks out of shape
- The kneecap slipped out of place. See kneecap dislocation
- The knee locks and won’t fully straighten
- The foot goes numb, cold or pale
- Your calf becomes painful, swollen or warm, especially if you have been on crutches
See your doctor or physio if
- The knee still gives way after 6 weeks
- You can’t fully straighten the knee after 2 to 3 weeks
- Pain and swelling aren’t improving week to week
Most MCL tears don’t need a surgeon. They need time, protection and steady work.