The medial collateral ligament (MCL) is the most commonly damaged ligament in the knee. The MCL can be sprained or torn as a result of a blow to the outer side of the knee, by twisting the knee, or by quickly changing directions while walking or running. MCL injury most often occurs in athletes, although nonathletes can also be affected. A physical therapist treats an MCL sprain or tear to reduce pain, swelling, stiffness, and any associated weakness in the knee or lower extremity.


What is an MCL Injury?

The MCL is a small, thick band of tissue on the inner side of the knee joint. It connects two bones—the thighbone and the shin bone—preventing the knee from bending inward toward the other knee. When the knee is hit on the outer side of the leg (eg, the left side of the left leg), or if the knee is twisted violently, the MCL can overstretch resulting in a partial or complete tear. MCL injuries commonly occur in football players who get "clipped" or hit on the outer side of the knee. Other causes may include twisting and turning while skiing, blows received on the soccer field, trauma experienced in a car accident, or simply turning the knee sharply while the foot is planted on the ground. Healing times vary from a couple of weeks to a couple of months, depending on the severity of the injury.

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How Does it Feel?

When you experience an MCL injury, you may feel:

  • Pain on the inner side of the knee
  • Swelling and bruising at the inner side of the knee
  • Swelling that spreads to the rest of the knee joint in 1 or 2 days following injury
  • Stiffness in the knee
  • Difficulty or pain when trying to bend or straighten the knee
  • An unstable feeling, as though the knee may give out or buckle
  • Pain or difficulty walking, sitting down, rising from a chair, or climbing stairs

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Signs and Symptoms

With an MCL injury, you may experience

  • A "popping" sound as the injury occurs
  • Pain and swelling in your knee
  • Difficulty moving your knee
  • Difficulty bearing weight on your leg for walking or getting up from a chair

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How Is It Diagnosed?

If you see your physical therapist first, the therapist will conduct a thorough evaluation that includes taking your health history. Your therapist will also ask you detailed questions about your injury, such as:

  • Did you feel pain or hear a "pop" when you injured your leg?
  • Did you turn your leg with your foot planted on the ground?
  • Did you change direction quickly while running?
  • Did you receive a direct hit to the leg while your foot was planted on the ground?
  • Did you see swelling around the knee in the first 2 to 3 hours following the injury?
  • Does your knee feel like buckling or giving way when you try to use it?

Your physical therapist also will perform special tests to help determine the likelihood that you have an MCL injury. Your therapist will gently press on the outside of your knee while it is slightly bent as well as when it is fully straight to test the strength of the ligament. The therapist will also check the inner side of your knee for tenderness and swelling and measure for swelling with a tape measure. The therapist may use additional tests to determine if other parts of your knee are injured, and will also observe how you are walking.

To provide a definitive diagnosis, your therapist may collaborate with an orthopedic physician or other health care provider. The orthopedic physician may order further tests, such as magnetic resonance imaging (MRI), to confirm the diagnosis and to rule out other damage to the knee. It also helps to determine whether surgery is required. MRI is not required in all cases but may be ordered. Your therapist or doctor may recommend a knee brace, a knee immobilizer, or crutches to reduce pain if the MCL injury is severe.

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How Can a Physical Therapist Help?

Your physical therapist will work with you to design a specific treatment program that will speed your recovery, including exercises and treatments you can do at home. Physical therapy will help you return to your normal lifestyle and activities.

The First 24-48 Hours

Your physical therapist may advise you to:

  • Rest the area by avoiding walking or any activity that causes pain. Crutches and a knee brace may be recommended to reduce further strain on the MCL when walking.
  • Apply ice packs to the area for 15-20 minutes every 2 hours.
  • Compress the area with an elastic bandage wrap.
  • Consult with a physician for further services such as medication or diagnostic tests.

Reduce Pain

Your physical therapist may use different types of treatments and technologies to control and reduce your pain, including ice, heat, ultrasound, electrical stimulation, taping, exercises, and hands-on therapy such as massage.

Improve Motion

Your physical therapist will choose specific activities and treatments to help restore normal movement in the knee and leg. These might begin with passive motions that the therapist performs for you to gently move your leg and knee joint, and progress to active exercises and stretches that you do yourself.

Improve Strength

Certain exercises will aid healing at each stage of recovery; your physical therapist will choose and teach you the correct exercises and equipment to steadily restore your strength and agility. These may include using cuff weights, stretchy bands, weight-lifting equipment, and cardio-exercise equipment such as treadmills or stationary bicycles.

Improve Balance

Regaining your sense of balance is important after an injury. Your physical therapist will teach you exercises to improve your balance skills.

Speed Recovery Time

Normal healing of time is a few weeks to a few months, depending on which tissues are injured and how severely they are injured. Your physical therapist is trained and experienced in choosing the right treatments and exercises to help you heal, return to your normal lifestyle, and reach your goals faster than you are likely to do on your own.

Return to Activities

Your physical therapist will discuss your goals with you and use them to set your work, sport, and homelife recovery goals. The therapist will design your treatment program to help you reach those goals in the safest, fastest, and most effective way possible. Your physical therapist will apply hands-on therapy, such as massage, and teach you exercises, work retraining activities, and sport-specific techniques and drills to help you achieve your goals.

Prevent Future Injury

Your physical therapist can recommend a home exercise program to strengthen and stretch the muscles around your knee, upper leg, and abdomen to help prevent future injury. These may include strength and flexibility exercises for the leg, knee, and core muscles.

If Surgery Is Necessary

Surgery is rarely necessary in the case of an MCL injury. If surgery is needed, you will follow a recovery program over several weeks guided by your physical therapist, who will help you minimize pain, regain motion, strength, and return to normal activities as quickly as possible after surgery.

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Can this Injury or Condition be Prevented?

To help prevent a recurrence of the injury, your physical therapist may advise you to:

  • Learn how to not let your knees collapse in toward each other when jumping, running, or turning quickly
  • Practice balance and agility exercises and drills
  • Always warm up before starting a sport or heavy physical activity
  • Follow a consistent strength and flexibility exercise program to maintain good physical conditioning, even in a sport's off-season
  • Wear shoes that are in good condition and fit well

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Real Life Experiences

Mark is a 35-year-old accountant who is an avid bowler on the weekends. He lives with his 100-lb Rottweiler dog. One morning, as Mark was quickly turning a corner into the kitchen to grab a ringing phone, his dog ran the other way and accidentally hit Mark’s knee on the outer side of his right leg. Mark lost his balance and fell sideways. His right foot got caught underneath the dog as his body fell to the right, forcing the outer side of the knee to buckle and the inner side of the knee to overstretch. Mark felt a sharp pain on the inner side of his knee, and fell to the ground. Mark felt immediate tenderness on the inner side of his knee, and he could not straighten or bend it.

Mark was able to see his physical therapist that day. The physical therapist performed special tests on the ligaments and cartilage in the knee. She found that just the MCL was injured, and that it was a mild sprain. She immediately applied ice and electrical stimulation to the area for 20 minutes. She wrapped Mark’s knee with a compressive wrap and instructed him to keep it elevated when he was sitting or lying down. She gave Mark crutches and taught him how to use them.

When Mark returned for his next visit, the physical therapist began gently moving the knee to reduce the stiffness. She taught Mark some exercises he could do at home to start improving his muscle strength. She helped him use equipment in the clinic to gently move, stretch, and strengthen his knee and leg.

Mark received physical therapy treatments for 2 weeks, after which he was able to walk and climb stairs with only a little discomfort. His therapist taught him a variety of balance and endurance exercises. By the third week, he was able to return to bowling, and walk around sharp corners in his house, while keeping a watchful eye on his energetic dog!

This story was based on a real-life case. Your case may be different. Your physical therapist will tailor a treatment program to your specific case., the official consumer Web site of the American Physical Therapy Association, ©[2018]