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The Complete Guide to MCL Injuries


There are seven ligaments that run through and around the knee that help provide stability for the largest joint in the body. Three of the ligaments are rarely injured unless one of the other four is damaged at the same time. Two of them—the anterior cruciate (ACL) and the medial collateral (MCL)—are the ones most susceptible to serious injuries. The MCL extends from the end of the thigh bone to the top of the shin bone on the inside of the knee. Although common in sports, most MCL injuries respond well to conservative (non-surgical) treatment.

ecmorgan / flickr

How They Happen

“MCL injuries occur when a sudden force or twisting motion is applied to the outside of the knee forcing the knee inward, most often when the foot is planted on the ground,” explains Jennifer Lewis, PT, DPT, ATC, a physical therapist at Athletes’ Performance in Phoenix, Arizona. “The injury may coincide with damage to other structures in the knee, including the ACL and the meniscus.”

MCL sprains involve stretching, partially tearing or rupturing the ligament. Typical scenarios involving MCL injuries in athletes include:

  • A football player who gets hit at the outside of the knee joint
  • A tennis player who plants a foot and changes directions quickly
  • A basketball player who lands awkwardly after jumping for a rebound
  • A gymnast who lands awkwardly during a floor or apparatus routine

By the Numbers

Percentage of all football injuries that involve the knee

Age range of athletes most likely to injure a collateral ligament

Percentage of all knee injuries seen in emergency rooms that involve collateral ligaments

Percentage of knee ligament injuries that do not involve contact with another athlete

Who’s At Risk

Athletes who play contact sports or who have to execute quick changes in direction are at the highest risk for MCL injuries. The short list includes skiers, hockey players and football players. Close behind are basketball, soccer, lacrosse, field hockey and baseball players, as well as those who play tennis, badminton and racquetball. Runners are less likely to sustain MCL damage, but it could happen if they misstep.


Symptoms depend on the severity of the injury and are classified according to the extent of the injury. MCL injuries are classified as grade 1, grade 2 or grade 3.

  • Pain on the inside of the knee
  • Tenderness to touch
  • Swelling, stiffness
  • Internal bleeding (grade 2)
  • Somewhat unstable joint (grade 2)
  • Unstable joint (grade 3)
  • Unable to put weight on the leg (grade 3)

Initial Treatment

  • Apply ice packs for 15-20 minutes, 3-4 times a day.
  • Rest the knee until symptoms significantly diminish or disappear.
  • Use an elastic wrap or bandage to compress the knee (to limit swelling).
  • Use a pillow or cushion to elevate the knee when sitting during the day or sleeping at night.

Comeback Strategy

Mild (grade 1) MCL sprains heal with rest and initial treatment methods. More severe sprains take weeks or months to heal, and recovering from MCL surgery requires months, although surgery is not automatically called for with grade 3 tears.

Wear a knee brace or sleeve recommended by your physician or physical therapist.

Wear athletic shoes that provide strong lateral support.


Incorporate these prehab exercises into your comeback routine:

  1. Hip Rotation – External - Sidelying
  2. Glute Bridge
  3. Prone Knee Tuck  - Physioball Rotation

How to Avoid This Injury

Athletes take risks when they play sports, and knee ligament injuries are among those risks. Some MCL injuries are not avoidable, but you can reduce your risk for an injury by following some of the suggestions below.

  • Avoid sudden increases in frequency, duration, or intensity of exercise.
  • Wear athletic shoes that provide strong lateral support.
  • Work with a knowledgeable coach to ensure proper, sport-specific technique

Movement Prep

Incorporate these exercises into your warm-up routine:

  1. Lateral Squats
  2. Forward Lunge
  3. Backward Lunge
  4. Knee Hugs

Jim Brown, Ph.D. has written 14 books on health, medicine, and sports. His articles have appeared in the Washington Post, New York Post, Sports Illustrated for Women and Better Homes & Gardens. He also writes for the Duke School of Medicine, UCLA School of Medicine, Cleveland Clinic and Steadman-Hawkins Research Foundation.

Tags: Hockey, Injury, Soccer, Knee Pain, Rehabilitation, Field Hockey, Knee, Football, Volleyball, Injury Prevention


  1. Jennifer Lewis, PT, DPT, ATC, Performance Physical Therapist, Athletes’ Performance, Phoenix, Arizona
  2. American Academy of Orthopaedic Surgeons
  3. Iowa Orthopaedic Journal
  4. National Institutes of Health (Medline Plus)
  5. University of Maryland Medical Center