What Is an MCL?
The MCL (medial collateral ligament) is an 8-10 centimeter band of tissue that runs along the inner edge of your knee. It helps keep your knee stable and working properly when you move.
Your knees are made of bones, ligaments, tendons, and cartilage. Ligaments connect one bone to another. There are two main types of ligaments in your knee:
Collateral ligaments are on each side of your knee. They keep your knee from moving side to side too much. These include:
- The medial collateral ligament (MCL) on the inner side of the knee. It connects your thigh bone (femur) to your shin bone (tibia).
- The lateral collateral ligament (LCL) on the outer side of the knee. It connects the thigh bone to the calf bone (fibula).
Cruciate ligaments are inside your knee joint and connect your thigh bone to your shin bone. They cross each other to form an X. These two ligaments control how your knee moves front to back and include:
- The anterior cruciate ligament (ACL) near the front of your knee
- The posterior cruciate ligament (PCL) behind the ACL
When your MCL is damaged, your knee can overextend itself, or bend too far in a direction that it’s not supposed to bend. You may heal on your own with basic care, rest, and rehab. But if your MCL knee injury is severe, you may need to have surgery.
What Is an MCL Tear?
Damage to your medial collateral ligament (MCL) is called an MCL tear. A tear can be either partial or complete. When some fibers in the ligament are torn, it is a partial tear. When the ligament is ripped into two pieces, it is called a complete tear.
An MCL tear is a common knee ligament injury for athletes. It can happen to anyone at any age.
MCL tear vs. sprain
An injury to your knee ligament is called a tear or sprain. The term sprain is used when a ligament is stretched or torn. Many knee sprains are mild. A torn MCL can range from mild to severe. A complete tear is severe.
MCL Tear Grading
If you have an MCL tear, your health care professional will rate how serious your injury is by using one of these three grades:
- Grade 1 is a mild tear. Less than 10% of the fibers in your ligament are torn, and your knee still feels supported. You’ll likely have some soreness and light pain.
- Grade 2 is a moderate (medium) tear. Your MCL is partially torn, and your knee may be loose when you move it by hand. You’ll likely feel intense pain and soreness on the inner side of your knee.
- Grade 3 is a severe tear. Your MCL is completely torn and your knee will probably be very unstable and loose. You’ll likely feel intense pain and soreness. You may have other knee injuries, too. It's common to also hurt your ACL when you have a grade 3 MCL tear.
How Do You Tear Your MCL?
If you collide with another player when you’re playing a sport and the outside of your knee is hit hard, your MCL may be injured. The force of being hit can cause the MCL, which runs along your inner knee, to stretch out far enough to tear. People who play football, hockey, and other sports where players impact other athletes with great force may injure their MCL this way.
You may also stretch or tear your MCL if your knee is suddenly pushed to the side, or if it twists or bends out too far. Other movements that can cause an MCL tear include:
- Quick stops and turns, like in basketball, soccer, or skiing
- Squatting
- Jumping and landing on your knee in an awkward position
- Lifting heavy objects
- Hyperextending (overstretching) your knee, which is common in skiing
- Regular pressure and stress on your knee. This causes your MCL to lose its stretchiness, like a worn-out rubber band
MCL Tear Symptoms
MCL injuries hurt. Most people feel pain along the inside edge of the knee. You may also experience other symptoms of an MCL tear, such as:
- Your knee may swell.
- You may hear a pop when your knee is damaged.
- Your knee may lurch to the side.
- You may find it hard to walk, or feel like you can’t put pressure on the leg with the hurt knee.
- You might feel like you are going to fall because your knee isn’t stable enough for walking, even if it doesn’t hurt to walk on it. Some people can walk in this case, but your knee feels loose, and it wobbles more than it should when you move.
- Your knee may feel stiff, or the joint may lock or catch when you move around.
MCL Tear Diagnosis
Your doctor will want to know how you got hurt and how you’ve been feeling and getting around since your knee injury.
They’ll check to see whether you’ve damaged your MCL and how badly it’s been stretched or torn. They may push on the inside of your knee to see how stable or loose the joint is and whether it hurts. They may also press on the outside of your knee when your leg is both bent and straight to check on how bad the problem is.
Your doctor may also want to do some imaging tests of your knee:
- MRI. An MRI study can show MCL damage, so your doctor will know how bad your tear is.
- X-ray. It won’t show your MCL, but it can show whether you have a broken bone.
- Stress X-ray. Although X-raysshow bones and not soft tissues such as ligaments, your doctor may be able to tell whether or not your MCL is torn with a stress X-ray. You’ll try to relax, and then your doctor or the person doing the X-ray will gently pull on the MCL side of your knee to see if it opens up farther than it should. If the image shows a bigger than usual gap between the shin and thigh bones, then the joint is loose, and your MCL is likely torn.
- Ultrasound. An ultrasound uses sound waves to show images of the inside of your body. This test can help your doctor know how serious your MCL tear is and if there is other damage to your knee.
MCL Tear Treatment
It’s rare for someone with an MCL injury to need surgery, as this ligament can often heal within a few weeks or months with the help of other measures. If you have a mild MCL strain, it can heal on its own with rest, ice, and other forms of self-care. Think of the word RICE to remember these steps:
- Rest your sore knee and keep weight off the joint.
- Ice your knee for 15-20 minutes at a time, waiting an hour in between.
- Compress the injury with an elastic bandage, to reduce swelling.
- Elevate (raise) your knee when you are resting, to help with pain and swelling.
While you recover at home, you can also:
- Wear a knee brace to prevent your knee from moving side to side. Keep your knee stable to allow your MCL tear to heal.
- Use crutches to walk to avoid putting your full weight on your knee.
- Take NSAIDs (nonsteroidal anti-inflammatory drugs) such as aspirin, ibuprofen, or naproxen to ease pain and swelling. Check with your doctor and follow the instructions on the label.
If your MCL tear is more serious, you may need:
- Physical therapy to rehab your knee when your MCL pain begins to fade. Your physical therapist will give you exercises to strengthen the leg muscles around your knee so it works properly.
- Surgery, especially if another part of your knee is also hurt. Professional athletes may also want to have surgery to fix their MCL tear to reduce the risk for a future MCL injury when they return to their sport.
Your surgeon will likely perform your surgery through tiny incisions (cuts) on your inner knee. MCL repair surgery can be done in two ways:
- Reattachment of the torn part of your MCL
- Reconstruction of your MCL using a graft (replacement tissue): An MCL graft can be made from tissue in another part of your body (such as your hamstring tendons) or from donor tissue.
After your surgery, your doctor will likely order physical therapy to strengthen your knee and increase your range of motion. Your total recovery time will depend on the grade of your MCL tear, the kind of surgery you had, if you also had surgery on other parts of your knee, and your age and overall health.
Whether or not you need surgery, you may be able to play sports again within a few weeks or months. Your doctor can let you know when it’s OK to get back to those activities, and they may ask you to wear a knee brace when you’re active.
MCL Exercises
After an MCL tear or surgery, your doctor or physical therapist may give you exercises to help you recover. MCL rehab exercises can benefit you in two ways: they strengthen the muscles that support your knee, and they stretch those muscles to improve your range of motion. This work can also help prevent future knee injuries.
Your MCL rehabilitation will focus on restoring mobility and knee strength, with a particular emphasis on joint stability. You may work on the following muscles:
- Quadriceps (front of thigh)
- Hamstrings (back of thigh)
- Abductors (outer thigh)
- Adductors (inner thigh)
- Gluteus medius and gluteus maximus (buttocks)
You will likely do MCL rehab exercises 2-3 days a week for 4-6 weeks. You may choose to continue doing these exercises to maintain strength and flexibility. Your doctor or physical therapist will give you instructions for each exercise, including a short warmup.
Here are examples of the kinds of exercises you may be instructed to do:
Heel cord stretch (you should feel this stretch in your calf and into your heel):
- Stand facing a wall with your uninjured leg forward and your knee slightly bent. Keep your injured leg unbent and behind you, with your heel flat and toes pointed in slightly.
- Place both hands against the wall at shoulder height. Do not arch your back.
- With both heels flat on the floor, press your hips forward toward the wall. Hold the stretch for about 30 seconds.
Standing quadriceps stretch (you should feel this stretch in the front of each thigh):
- With one hand, hold onto the back of a chair or a wall for balance.
- Bend one knee and bring your heel up behind you toward your buttock.
- Grasp your ankle with your free hand and gently pull your heel closer to your body.
- Hold the position for 30-60 seconds, being careful not to arch or twist your back.
- Repeat with the opposite leg.
Supine hamstring stretch (you should feel this stretch at the back of each thigh and behind your knee):
- Lie on the floor with both legs bent.
- Lift one leg off of the floor and bring your knee toward your chest. Clasp your hands behind your thigh, below your knee.
- Straighten your leg and gently pull it toward your head, until you feel a stretch. (You may loop a towel around your leg and hold the ends if it is too difficult to clasp your hands.)
- Hold the position for 30-60 seconds, being careful not to pull on your knee joint.
- Repeat with the opposite leg.
MCL Tear Recovery Time
The time it takes to fully recover from an MCL tear depends on the severity of your injury. Other factors can also affect how long it takes, such as whether you had surgery, and your age and overall health. The following is a general guideline of what to expect:
- A grade 1 (mild) MCL tear usually heals in 1-3 weeks.
- A grade 2 (moderate) MCL tear usually heals in 4-6 weeks with treatment.
- A grade 3 (severe) MCL tear usually takes 6 weeks or longer to heal with treatment. If you have surgery, it can take more time.