Medial Collateral Ligament Injury (MCL)

medial-collateral-ligamentImage courtesy of Visible Body

About MCL injuries

  • One of the most common type of ligamentous knee injury (40%)[1] and account for about 8% of all knee injuries[2]
  • Studies showed that the most two common sites of superficials MCL (sMCL) injuries were at the endpoints[3] :
    • the femoral attachment or;
    • the tibial attachment.
  • Deep MCL and posterior oblique ligament (POL) injuries are also possible (not shown in picture above).

What to do if you have a MCL injury

  • Consult a sport physiotherapist ideally in a well reputed sport clinic.
  • Consult an orthopedist; only them are allowed to prescribe MRI and microsurgery inspection.
  • Depending on the grade, the knee might need to be protected with a short-hinged brace for 3 to 6 weeks.
  • Your physio or ortho will give you appropriate exercises.
  • Maintaining good muscle tone during walking and exercising is important to stabilize the knee – as opposed to letting your weight loose on your leg without tonus. (source: personal experience)
  • Wearing shoes that are somewhat slippery will reduce stress on the knee when doing sudden movements. If your shoes has too much grip with the floor, it can result in a more intensive  forces on your knees. This does not apply when outdoor with ice where safety is #1. (source: personal experience)
  • When turning, avoid using the tip of your foot which will create a lever effect and increase the torque (moment-force) on the knee; rotate using the heal instead. (source: personal experience)
  • Avoid taking the stairs and hold up the ramp if you must to stabilize. By stabilizing with your hands on the handrail you reduce stabilization requirements on your MCL.
  • Read more on exercises to avoid below.


If you hear various doctors you will notice that two different classification of grading are present, the American Medical Association (AMA) Classification and the Hughston Modification of the AMA Classification. The latest classification (Hughston) is not only based on joint laxity but also severity of tenderness and quality of the endpoint. Some practitioners still only use the laxity to grade the injury which represents the earlier AMA classification dating 1966.

The Hughston Modification of the AMA Classification

  • based on joint laxity and injury severity
    • severity graded by extent of tenderness and quality of the endpoint with valgus stress at 30 degrees of knee flexion
      • often referred to as “degree” of injury
  • revised in 1994
  • Grade I — First-degree injury
    • mild
    • localized tenderness
    • firm endpoint
    • no joint laxity
    • stretch injury or few MCL fibers torn
      • no significant loss of ligamentous integrity
  • Grade II — Second-degree injury
    • moderate
    • more generalized tenderness
    • firm endpoint
    • +/- mild increase in joint laxity
    • incomplete / partial MCL tear
      • some MCL fibers remain intact, generating the firm end point
  • Grade III — Third-degree injury
    • severe
    • generalized tendernesss
    • no endpoint with valgus stress
    • increased joint laxity
      • third-degree injuries are further subdivided by joint laxity, described by the original AMA system
      • Grade 1+: 3-5 mm
      • Grade 2+: 6-10 mm
      • Grade 3+: > 10 mm
    • complete MCL tear

Recovery and Rehabilitation

  • Warm up before doing exercises
  • When you start sweating you are warmed up
  • Gently stretch all muscle groups after warming up
  • Do not injure again during the recovery period. If you must do high weight carrying and climbing stairs during your work, ask your doctor if wearing a brace or getting time off work is good for you.
  • For each pound you loose, you will reduce by the stabilization requirements on your MCL during squatting as if you had lost 4 to 5 pounds. Stabilizing a 200-pounds body-weight when squatting is equal in stabilization requirement on the MCL as if you were 1000-pounds and standing up on a flat surface.[4]

Things Not to Do If You Have a MCL injury

The following exercises can further injure your MCL & knee and should NOT be done until you are ready. Your sport physio can guide to know when you can restart these exercises.

Do NOT do :

  • Do not do squats past 90 degrees of knee flexion
  • Do not do high Impact and plyometric exercises
  • Do not do leg extension machine (quadriceps extensions)

    View this post on Instagram

    A post shared by Edu Rodrigues (@eduptrodrigues) on

Complementary/Alternative Therapies

This section is for educational purpose only and does not represent a health advise. Always consult with your local health authorities on available treatments.

  • Prolotherapy with other products than ozone have sometimes been helpful[6], but there is not enough scientific support to recommend these therapy. Note that ozone therapy is some form of prolotherapy.
  • Ozone therapy. Ozone therapy is one form of prolotherapy. It has very good anecdotal results in knee injuries, both on cartilage regeneration and tightening of ligaments. Finding a good therapist is however hard. Dr. Robert Rowen, MD and Terri Su, MD have a good clinic in California. If ozone fails, there is no harm (if done by a competent doctor) and one can still have surgery; but if you have surgery and it fails, the surgery may cause irreversible damage. Ozone therapy is also good for knee osteoarthritis[5].
  • Advanced soft tissue release (ASTR). Sometimes when recovering from injuries and surgeries scar tissues develop and merge various layers together causing pain during motion. Your healthcare provider should not offer these treatments on a fresh injury.

Interesting Research

Administrations of Peripheral Blood CD34‐Positive Cells Contribute to Medial Collateral Ligament Healing via Vasculogenesis





4. Harvard Health Publishing



Rehabilitation after Injury to the Medial Collateral Ligament of the Knee


This article is for educational purpose only and should not be used to diagnose and treat any medical condition. It is not a incentive to self-treat. Always consult with your local health authorities on available treatments.