What on earth is a knee MCL sprain? (and how to get rid of it)

The knee is one of the body’s most complex joints, both structurally and functionally. It serves a role both for movement (e.g., walking) and stability (e.g., standing and sitting). Because of constant use, the structures within the knee complex – such as ligaments, tendons, cartilages, and even the kneecap itself – become very prone to injury.

For this article, particular emphasis will be placed on the injuries concerning one of the four major ligaments of the knee joint – the medial collateral ligament (MCL).

What Does the MCL Do?

The MCL is a tissue band that links together the tibia (shin bone) to the femur (thigh bone). It provides stability to the medial side [inner side] of the knee and limits the movement of the knee inward, gives rotational stability, and guides the joint through a range of motion.

Proprioceptors, special receptors that receive information about our limbs’ position in space, our movement, and the effort we exert when lifting, are also found within the MCL.

What Is an MCL Injury?

When an outside force hits or pushes the outer side of the knee too hard, the MCL may extend too far out, causing a sprain or tear. A sudden push to the side, twisting, or overbending movements may also cause injury.

This type of injury is more common with athletes playing sports that would entail a lot of these movements or where the risk of colliding with other players is high, such as in football, soccer, hockey, or skiing.

MCL Injury Symptoms

A popping sound at the time of injury is usually experienced. Regardless of the severity of the injury, the pain will be felt along the inner side of the knee. You may also notice swelling and tenderness, as well as bruising, on the same side (take note that some of these may not occur immediately). The other areas of the knee joint may also become swollen after a few days.

After a while, it may become harder to walk and move. The knee joint may lock or catch while moving or you may feel there is stiffness of the knee. Going up the stairs or sitting on a chair may become a challenge, as it becomes more difficult to bend the knees. It may also be hard to stand up from sitting due to difficulties in straightening the leg. A person may also feel that their knee is “loose,” as stability is compromised.


The health care professional (a doctor or a physiotherapist) would first get a history of the patient’s health. They will then ask about the instances surrounding the injury to the knee – how and when it occurred – as well as the symptoms that the patient has felt since.

A physical examination to determine the extent of the injury will also be done. The professional will check on the range of movement of the knee and if there is swelling or tenderness in the area. A doctor will also perform stress tests where force will be exerted on the outside of the knee when the leg is bent and straight.

The doctor might order several imaging tests to confirm the results of the physical examination:

  • MRI: A magnetic resonance imaging study can show the extent of the medial collateral ligament damage.
  • X-ray: produces an image of the bones within the knee complex to check for fractures.
  • Stress X-ray: As the x-ray is being done, the patient will be asked to relax, then the professional will gently pull on the MCL side of the knee to check if it opens up farther than it should. If the gap between the hip bone and the shin bone is more significant than usual, this indicates that the joint is loose, and the MCL is likely torn.

An injury to the MCL may be classified into three categories. This depends on the degree to which the ligament is damaged.

  • Grade I: less than 10% of collagen fibers are torn; there is some tenderness but no instability; pain is felt when force is applied on a slightly bent knee.
  • Grade II: there is tenderness but no instability; pain and swelling are more significant than Grade I injuries; pain and significant tenderness is felt on the inside of the knee when force is applied; the knee joint is moderately lax
  • Grade III: complete rupture of the MCL resulting in instability; significant pain and swelling; difficulty bending the knee; the knee joint is lax during a stress test


For acute (sudden and overwhelming) injury, professionals advise the use of the PRICEMEM method:

  • Protection: professionals may recommend using a brace or crutches to protect the knee as it heals.
  • Rest: allow the knee to rest by avoiding activities that exacerbate the pain, such as pivoting and walking for long periods.
  • Ice: put ice packs on the knee to decrease the swelling and alleviate pain. This is usually done for 15-20 minutes, repeating as necessary with one-hour intervals in between.
  • Compression: professionals may prescribe the use of a tight, elastic bandage around the knee to cease the swelling.
  • Elevation: raising the knee by propping it up above the waist while seated can also reduce swelling.
  • Manual Therapy: some joint mobilization techniques may be done or recommended by the professional.
  • Early Motion: moving the knee is still necessary for healing. This will be done passively at first, then actively with some help from another person, then on your own.
  • Medication: To reduce the pain that a patient may be feeling, the doctor may prescribe non-steroidal inflammatory drugs (NSAIDs) such as aspirin, ibuprofen, or naproxen. Patients should strictly follow the instructions on the label or the doctor’s prescription to avoid adverse effects.

Physical therapy treatment for MCL injuries depends on the grade of the injury:

Grade I

Ice, compression, and elevation are used as much as possible during the first 48 hours of injury. Incomplete tears are generally treated with temporary immobilization and the use of crutches for pain control.

As pain and swelling subside, some exercises to maintain and strengthen the knee muscles are gradually done. The patient is also encouraged to put weight on the affected leg but should be dictated by the level of pain that he/she is feeling.

Grade II/III

Special care is needed to protect the ends of the ligament. They need to be left to heal without disruption. Thus significant stresses on the affected structures are avoided until three to four weeks after injury.

Meanwhile, grade III injuries are treated depending on the degree of affection. . Grade III injuries may take 8 weeks or even more to heal. If it is combined with another injury, the medial knee injury is generally rehabilitated first.

Surgical intervention for isolated MCL injury is rare since the ligament can heal within a few weeks or months with the aid of other measures. However, this may be warranted if other knee structures are affected (such as the anterior cruciate ligament or the meniscus) or if there is persistent instability of the joint even after strictly following non-surgical measures.


Here are several tips to prevent MCL injury:

  • Before doing a particular sport or exercise, sufficient warm-up and strengthening the muscles around the knee would help prevent injuries to the medial collateral ligament. Exercises would target leg and core muscles, balance, landing techniques, and proper joint alignment. High-risk movements, such as side-cutting and single-leg landing, may be included in the warm-up to ensure that the knee can react appropriately to the movements.
  • Wear well-fitting shoes and appropriate protection during sports.
  • Monitor your body’s endurance as you exercise. Injuries occur more frequently if a person is tired while performing an exercise.
  • Avoid exercising with an existing injury.
  • Take extra caution when running on uneven surfaces, as the risk of falling and twisting the knee is very high.
  • Take enough time to recover after an MCL tear.
  • For athletes, exercise and stay strong throughout the year.

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