What is an MCL?

The medial collateral ligament (MCL) and lateral collateral ligament (LCL) are found on the sides of the knee.  The MCL (on the inside) connects the femur to the tibia and the LCL (on the outside) connects the femur to the fibula.  The collateral ligaments control sideways motion in the knee and assist the cruciate ligaments in controlling forward/backward movement in the knee.

Photo Credit: Central Coast Ortho

How Do You Tear the MCL?

Injuries to the MCL are usually caused by a direct blow to the outside of the knee that pushes the knee inward. The LCL can be injured by a blow to the inside of the knee. MCL injuries are far more common than LCL injuries.

What are the Symptoms of an MCL Injury?

Pain at the inside of the knee. Pain can be felt along the MCL – from just above the joint line (where the femur and tibia meet) to just below the joint line. Typically, the knee is swollen over the site of the injury. The knee will feel unstable when trying to walk. In addition to the ligament’s stability being compromised, the pain and swelling also inhibits the quadriceps from helping provide support.

How is the Diagnosis Made?

The most accurate way to make a diagnosis is through a good history. The patient can often describe the injury producing situation – foot was planted and got hit on the outside of the knee. The doctor’s examination of the knee includes checking for areas of pain and gently testing the side to side stability of the joint.

Injured ligaments are considered “sprains” and are graded on a severity scale.

  • Grade 1 Sprains. The ligament is mildly damaged; it has been stretched slightly but still provides stability to the knee.

  • Grade 2 Sprains. The ligament is partially torn; stability is compromised but there is still an end-point when the knee is lightly stressed with a manual test.

  • Grade 3 Sprains. The ligament is completely torn, and joint stability is further reduced. With the manual test, the joint opens up until the joint capsule resists the motion.

Because of the injury mechanism, other structures in the knee may have been injured. The medial meniscus and the ACL may have also been injured. The doctor’s exam of the knee will look at these sites as well.

Are X-rays and MRI Needed?

X-rays will not show the injury to the MCL (or other ligaments or cartilage), but can show whether the injury also caused a fracture in a bone.

MRI scans can provide images of the ligaments and other soft tissues. The information from the MRI may not change how the MCL is treated, but information about other structures may affect treatment plans.

What is the Treatment for MCL Injuries?

Injuries to the MCL rarely require surgery. Bracing the knee to protect the ligament from sideways forces is important. The sooner a brace is utilized after the injury (within the first couple of days), the better the outcomes for the ligament to heal. Rehabilitation exercises (basic isometric exercises and resistance training exercises) should be initiated soon after the injury. Based on the severity of the injury, and individual recovery, your doctor will recommend that the brace be worn at all times initially and then gradually decrease the use of the brace. For example, the brace may be prescribed full-time for the first 6 weeks and then worn during workouts and during sports for 3 months. Your doctor will give you a specific timeline based on your injury and your progress.

When Can I Return to Sports?

A progression needs to be followed to limit the chance of re-injury or sustaining a different injury. Strength needs to be restored with resistance exercises. The brace will be worn during the return to sports phase and worn once back playing sports. Once the athlete can walk without a limp, straight ahead running can begin. If the athlete can run without a limp, then agility drills and sport drills can be started. Once these drills can be performed without a limp or favoring the knee, the athlete can return to sports.

To set up an appointment for further evaluation, please call (208) 336-8250.


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