The medial collateral ligament (MCL) is one of the four ligaments that provide the stability of the knee joint. A ligament is made up of tough fibrous tissue that connects bone to bone. It helps to limit the amount of movement in the joint by preventing too much motion. The four main stabilizing ligaments of the knee are the anterior cruciate ligament (ACL), the posterior cruciate ligament (PCL), the medial collateral ligament (MCL) and the lateral collateral ligament (LCL). The knee joint, more than any other joint, depends on these ligaments in order to provide its stability.

The MCL runs from the end of the femur (thigh bone), across the knee joint, and attaches to the top of the tibia (shin bone), on the medial (inside) on the knee. The MCL prohibits those two bones on the inside of the knee from gapping or opening too far. The MCL is made up of two parts, a superficial layer and a deep layer. It is interesting to note that the deep layer is connected with the medial meniscus and some injuries can involve both of the structures.

How is the medial collateral ligament injured?

Since the MCL is located across the medial surface of the knee, it can be damaged most often by a force or blow to the outside of the knee. You may see this happen in baseball when a base runner slides full speed, into the base with a cleat up in the air. If the outfielder has his/her foot against the base (in the base line), and the base runners foot might crash into the outfielders knee. This force may cause the inside of the knee to “gap”, which may result in a stretch or tear to the MCL. This is one of the reasons that it is illegal, in high school football, to block another player below the waist. A helmet to the outside of the knee can very well damage the MCL. The MCL can also be injured when the foot is firmly planted on the ground, and the body is rotated around it, causing a twisting at the knee.

The MCL can be the only structure injured, or it can be only 1 of a few structures injured in a complex injury. Often, the anterior cruciate ligament and medial meniscus (cartilage in the knee) are damaged as well.

What are the signs and symptoms of the injury?

Sometimes a “pop” or “snap” will be heard or felt when the injury happens. Usually, immediate pain can be felt to the inside of the knee. Although the medial collateral ligament will be tender to the touch, there may not always be significant swelling. In a more severe injury, someone may complain of a feeling of instability, like their knee “may give out”.

There are three categories of ligament injuries, and they are rated I to III, depending on their rate of severity:

Grade I MCL Tear:

*This is considered an incomplete tear (less than 50% of the fibers are torn).
*Little, or no swelling.
*Range of motion is normal.
*MCL is tender to the touch.
*No joint instability.
*Return to normal ADL’s (activities of normal living) very quickly.
*Most athletes return to sports within a couple of weeks.

Grade II MCL Tear:

*Also considered an incomplete tear, but with more of the ligament fibers torn (>50%).
*Little or no swelling.
*Range of motion is restricted.
*MCL is tender to the touch
*Some instability is present.
*Pain is more significant.
*May benefit from the use of a hinged brace temporarily.
*Athletes may take 3-4 weeks or more to return to sports.

Grade III MCL Tear:

*Considered a complete tear.
*Moderate swelling.
*Range of motion is restricted, often difficulty bending the knee.
*Pain and tenderness is increased.
*Instability is present. The knee is now unstable.
*A knee brace or immobilizer is often needed, along with crutches to limit weight bearing initially.
*Healing may take 6 weeks or longer. Complete rehabilitation from a grade III tear may take up to 3-4 months.
*The ACL and meniscus may be damaged as well.

Treatment for MCL injury:

Immediate treatment after injury consists of RICE (Rest, Ice, Compression & Elevation).
Crutches may be required if you are unable to walk without pain or limping. When instability is present in the knee, a brace may be worn for comfort and support, while the ligament is healing. Nonsteriodal anti-inflammatory drugs (NSAIDs) such as Motrin, Tylenol or Advil may be beneficial.

Physical therapy is recommended to help restore range of motion, strength, and flexibility to help speed the return to activities and sports. Initial goals of physical therapy are to decrease edema (swelling) and restore full range of motion in the knee. The rehab will then progress to strengthening, with emphasis placed on the quadriceps (front of the thigh), hamstrings (back of the thigh) and calves. Return to sports will only be allowed when strength goals have been met and patient may do running, cutting and jumping activities without pain. Surgery is rarely required for MCL injury. Even complete tears can be treated conservatively. Surgery is more often done if injury includes the ACL, and/or meniscus damage. Athletes with severe, grade III injury may benefit from a functional knee brace to prevent re-injury when returning to high contact sports.

If you have any questions, or are having any problems with your knees, please stop by the clinic or give us a call. We would love to answer any questions you have and help you get back to what ever it is that you want to do.

Magee,D: Orthopedic Physical Assessment. Third Edition.W.B. Saunders Company. 1997.