A tear or sprain in the medial collateral ligament (MCL) are two common types of MCL injury.  The MCL is made up of a strong band of connective tissues on the inside of your knee that connects your femur to your tibia (along with the other three major ligaments of the knee: ACL, PCL, and LCL). Basically, the MCL stabilizes the inside of your knee, preventing it from caving inward excessively, like knee valgus.

The MCL can tear or sprain from non-contact factors, such as excessive twisting and lateral bending of the knee when you quickly turn and change direction while you sprint, jump, or stand in place. Of course, you can also get it from someone who collides into you or hits you from the side like in American football, martial arts, and soccer. In my own experience as a former breakdancer, a MCL injury — even if it is minor — can invoke fear of movement and anxiety.

I remember one MCL injury incident during a hip-hop practice session with some friends in 2004. One of my friends felt a sharp pain in the inside of her knee after she turned it inward during a choreography. She had to leave early and could barely walk to her car from the studio. My friends and I were worried that she might be out of commission for a month or longer, but fortunately, she bounced right back in a week after getting her knee checked the next day followed by some rest.

There was no tear in her medial collateral ligament or other ligaments of her knee. Her doctor didn’t really know what exactly caused her inner knee pain, which lasted for about three days. The MCL might have been strained hard enough to cause that sharp pain, but not enough to cause long-term pain or serious damage. Or it could have been something else that is not MCL-related. Regardless, she was able to walk and climb stairs normally again and continue to practice with us in a week.

Knee pain like this sometimes can resolve by themselves with hardly any treatments, but for some people with a more serious MCL injury, it can limit how much they move, increase their fear of movement, and end their athletic or dance career. A review of the anatomy, biomechanics, the nature of pain, and treatments can help us assuage some of the uncertainty and fear we may have should we sustain a MCL injury (or most knee injuries).

Medial collateral ligament anatomy

Specifically, the MCL is made up of three parts to minimize the risk of getting a MCL injury: the superficial MCL, the deep MCL, and the posterior oblique ligament (POL). These parts are not compartmentalized; rather, they blend together so that the boundaries of each component are not easily noticed.

The superficial MCL attaches at the medial epicondyle of the femur with the semimembranosus tendon, while at the other end of the ligament, it attaches to the medial side and back of the tibia.

knee ligaments

Image: BruceBlaus

The deep MCL is made up of the meniscofemoral and meniscotibial ligaments. The meniscofemoral ligament inserts just below the superficial MCL at the femur and at the medial meniscus. The meniscotibial ligament continues from the medial meniscus to the edge of the medial tibial plateau at the articular cartilage. Although the latter ligament is attached to the meniscus, it offers no stability to the cartilage.

The fibers that line up along the superficial MCL fan out toward the back as it approaches the POL, which also blends into the semimembranosus tendon, medial meniscus, the joint capsule and just below the articular surface of the knee. This section of the knee is called the posteromedial corner. Together, these three parts of the MCL resist forces that push the knee into an excessive valgus position (moving toward the midline of your body) or twist the knee that can cause a MCL injury.

Each layer of the MCL provides a different support in relation to how the knee is flexed or extended. The superficial MCL helps to stabilize the knee when it is externally rotated with the knee flexed at 30 degrees. Meanwhile, the deep MCL helps to stabilize the knee when it is internally rotated throughout the entire range of motion of the knee.

When you flex your knee, the semimembranosus tendon supports the superficial MCL and POL, while the vastus medialis muscle of the quadriceps support the superficial MCL when you extend your knee. How much these supports can help minimize your risk of sustaining a MCL injury would depend on how well-trained you are.

A team of researchers, led by Dr. Milford Marchant, Jr., from Duke University, published a review that mentioned that there is a “wide variation” of how the ligament fibers reinforce the knee joint. This may explain some people with “good muscular support” can continue to perform after an injury and “well-trained athletes” can still “endure higher stressors” at the knee without getting a MCL injury.

MCL injury cannot be fully understood without considering the posteromedial corner since they share the anatomy and movement of the superficial MCL. Marchant, Jr. et al. speculated that the posteromedial corner injuries are studied less because it is usually grouped with MCL injuries. Parts of the posteromedial corner include the POL, semimembranosus tendon, oblique popliteal ligament, and posterior horn of the medial meniscus.

Like the MCL, the posteromedial corner stabilizes the knee when it extends, a common function when you walk or run. The corner slackens when you flex your knee (and the superficial MCL takes over the stabilizing job) or when your tibia externally rotates. In full knee extension, the POL prevents the tibia from sliding back and valgus knee (and opposed to varus knee).

The medial articular nerve, which is part of the saphenous nerve that is located toward the end of the femoral nerve, innervates the MCL, while tiny branches of blood vessels and lymph vessels from the superior and inferior genicular arteries provide nutrients and remove metabolic wastes from the ligament.

Sometimes MCL injuries occur with an ACL tear or PCL tear. In cases like these, clinicians must decide whether a patient would need surgery or not as well as risk assessment based on each individual case.

What causes a MCL injury or tear?

MCL injuries are mainly caused by direct hit from the lateral side of the knee while the foot is planted on the ground. This causes the knee to “cave in” and is quite common in rugby, American and Australian football, and soccer. Non-contact MCL injuries (valgus stress) are common in skiing and cutting and turning sports like basketball.

ACL vs MCL injury symptoms

Other than the obvious difference of the site of the injury, both ACL and MCL injuries have similar symptoms, such as swelling and pain at the knee joint. However, an ACL tear has a “popping sound” at the time of the injury while a MCL injury does not. So if you heard a “pop” in your knee when you got hurt, it is likely an ACL tear.

MCL injury diagnosis

In addition to your health and lifestyle history, a physician or physical therapist may check your knee’s range of motion, tenderness, pain, and swelling. They may also use imaging like magnetic resonance imaging (MRI) and an X-ray to check your knee.

Video by Physiotutors.

A MCL injury is categorized into three grades:

  1. Grade I: microscopic tears in the MCL fibers; pain and swelling may or may not be present; may have full range of motion;
  2. Grade II: partial tear of the MCL; limited range of motion; pain may be felt at the end range of motion;
  3. Grade III: complete tear of the MCL; high tenderness in the MCL particularly at the femoral insertion; one or more knee ligaments may be injured, too. This is where reconstructive surgery is likely required.

A valgus stress test may be used to test for a MCL injury, which tests laxity — looseness or slack — of the MCL ligament. This is compared with the opposite, uninjured knee. First, the clinician palpates along the MCL and the inner part of your knee. If you feel tenderness, you may have a MCL injury.

While you are lying on the examination table on your back with your injured knee slightly flexed, the clinician would put one hand on your outer knee and the opposite hand on your ankle. Then your knee is gently rotated in and out. Any pain felt may also be a sign to a MCL injury as well as an increase of the joint space at the inner knee.

A positive valgus stress test would be laxity at 30 degrees of flexion, which indicates injury to the superficial MCL. Laxity at 0 degrees of flexion means that the deep MCL is injured.

MCL injury treatment

Like most types of knee pain, treatments for a MCL injury depends on the grade, severity of the symptoms, and other factors. These include  the following:

RICE method

RICE stands for “Rest, Ice, Compression, Elevation” and it is used to manage pain. However, in 2015, the originator of RICE — Dr. Gabe Murkins recanted his position about the method that he popularized in his 1978 book “Sportsmedicine Book.”

He wrote that inflammation is necessary for healing tissues, and icing the injury site can delay such effects. “The inflammatory cells called macrophages release a hormone called Insulin-like growth Factor (IGF-1) into the damaged tissues, which helps muscles and other injured parts to heal,” Murkins wrote. “However, applying ice to reduce swelling actually delays healing by preventing the body from releasing IGF-1.”

Scialoia and Swartzendruber from St. Joseph’s College of Maine recently wrote in “The Sports Journal” that there is a “lack of definitive evidence that supports compression” to be used with icing when treating a muscle injury. This is based on several studies they reviewed that found poor levels of evidence to support that compression and elevation have any benefits to help the healing process.

However, the researcher mentioned that compression and elevation may induce a placebo effect to patients. If such treatment is effective for patients to alleviate pain and psychological stress during their recovery, then they “may be justified to continue their use.” If there is another effective treatment that can be used to substitute compression and elevation, that the former should be used instead.

One potential replacement for the RICE method is the MEAT method, which stands for “Movement, Exercise, Analgesics, Treatment.”

See more on the evidence behind icing pain and injury recovery.

Movement and exercise

In relation to the knee joint, movement treatment refers to moving your knee through a range of motion that is pain-free or with very little pain without putting on extra resistance. Exercise refers to placing load upon the knee, such as strength training using a machine or with a resistance band.

A 2016 MCL injury review by Logan, O’Brien, and LaPrade said that for a grade III injury, movement therapy, quadriceps activation, and regaining a normal gait should be done as soon as possible after a MCL reconstruction surgery. After being in a non-weight bearing hinge brace for six weeks, they suggested that the next steps should be “functional exercise progression” and “proprioceptive-based exercises.” Avoid valgus knee movements during exercise therapy.

Some of the exercises include supine straight leg raise, seated leg extension, hip abduction (e.g. clam shells), and hip extensions. The exercise variables, such as how many reps you do and exercise intensity, would depend on each person’s performance and rate of progress monitored by a physical therapist or another qualified healthcare professional.

As you move better with improved strength, speed, range of motion, and stability, sports-specific exercises should be used as part of the latter phase of rehabilitation.


Scialoia and Swartzendruber stated that analgesics should be used to manage pain since pain “limits one’s ability to efficiently move the injured area through a full range of motion. They warned that these painkillers, commonly known as NSAIDS (nonsteroidal anti-inflammatory drugs), block a compound called prostaglandins, which is essential for forming blood clots, controlling infection, and processing inflammation. Thus, long-term reliance on NSAIDS may delay the healing process.

Be sure to follow your physician’s recommendations if you are taking NSAIDS for your MCL injury recovery. 


Treatment in the MEAT method is a vague term that can mean many things. After all, medications and exercise are two forms of treatments. Treatments could mean various non-drug and non-surgical interventions to manage pain, function, and well-being of the patient. These may include massage therapy, better sleep, regaining self-efficacy, and even psychological treatments like cognitive behavioral therapy.

Be aware that many treatments have unsupportive claims that may cause harm to your health, or at best, leave your wallet a little lighter.


While conservative treatments are generally recommended for most people with grade I or II MCL injuries, some research suggests that reconstructive MCL surgery should be used to  repair the ligament since non-operative treatments may increase the risk for knee osteoarthritis, valgus knees, and less stability in the knee during rotations.

The type of surgery you may need would depend on the severity of the tear,, the presence of an ACL and/or PCL tear, and other factors that may influence the pain and functional outcomes.

Researchers from the Hospital Universitario La Paz in Madrid, Spain, described several types of MCL surgeries that a surgeon might use.

Primary repair of bone avulsion

This type of repair involves using sutures to reattach a ligament to the bone if there is a bone avulsion  — tear of a piece of bone with the ligament — involved at the tibial or femoral insertion. A surgeon might use anchors and/or staples with the sutures.

Primary repair for MCL entrapment

In a MCL tear, the MCL can be “caught” under the medial meniscus or at the pes anserinus tendons. A surgery would get it out of entrapment and reattached.


When conservative treatments fail to allow the MCL to heal properly, reconstructive surgery is recommended. This type of surgery involves using tissues from another part of your body that are similar to the ligament for repairs and implants. Sometimes biomaterials (plastics implants that mimic the properties and functions of living tissues) are used instead if grafts from other tissues are not available or if the procedure is too risky.

Please consider that the information about treatment and diagnosis are for educational and informational purposes only, not medical advice.

Massage therapy and MCL injury

Patients with a MCL injury probably may have a good idea about the nature of their injury because of their orthopedic physician or reading different reliable sources about it online. However, they might not what the recovery time would be or the rehab process would be like.

“My role is to inform my client that if the GP hasn’t discussed the need for surgery then conservative management of ligament strain will be the best option,” said Aran Bright, who is a massage therapist and myotherapist at Bright Health Training in Sunshine Coast, Australia. “Informing the client that they will likely recover to full function and pain free within a six- to eight-week period.”

Bright suggests that massage therapists can help bring some clients pain relief by massaging the adductors and medial hamstrings. “It may be appropriate to consider some lymphatic drainage massage if there is minor swelling around the site of the MCL. Any form of gentle massage around the area should bring relief, and I always stay away from aggressive or painful massage, especially in the case of an injury.”

A MCL injury can make clients worry about further damage to their knee, like lateral meniscus tear or damage to the ACL or PCL, Bright said. Clients may associate knee pain and injury with “complex surgery and disability.”

“It is really important to highlight recent research to them that shows even with meniscal damage, many people can be pain free and have normal function,” Bright said.

He refers to a recent study published in early 2020 that highlights 97% of 230 knees had no pain or other symptoms despite having various types of “abnormalities,” such as medial meniscus tear, bone marrow lesions, Baker’s cyst, and per anserine bursitis. Twelve of these subjects had various grades of MCL tear—except for grade 3. Using the latest high-resolution magnetic resolution imaging (MRI), the team of researchers, led by Dr. Laura Horga from the University College London and the Royal National Orthopaedic Hospital, concluded that clinician should make diagnosis “primarily based on patient’s medical history and physical examination,” not just from examining the MRI scan.

“So while meniscal damage should never be ignored, the best focus is on rehabilitation exercise and improving strength and function to the area. Helping them to understanding that conservative care can be the best strategy to manage knee injuries and that many athletes compete with ‘damaged’ knees is one approach I use to normalize knee injuries and encourage a positive approach to injury management.

“Citing studies of asymptomatic populations with meniscal damage (in both athletic and general populations) is one of the best tools we have to show that knee damage doesn’t automatically mean disability or surgery.”

Thinking back of my friend’s knee pain experience made me more aware of knee injuries that day, and how it can stop us from enjoying activities that we take for granted. Almost all physical activities carry some risks in sustaining a knee injury, but some knowledge in prevention and treatment can help us recover the best we can.


Further Reading

Pain Is Weird

Pain Behind the Knee Causes

4 Tissue Loading Progressions to Help With Knee Pain

Website | + posts

A native of San Diego for nearly 40 years, Nick Ng is an editor of Massage & Fitness Magazine, an online publication for manual therapists and the public who want to explore the science behind touch, pain, and exercise, and how to apply that in their hands-on practice or daily lives.

An alumni from San Diego State University with a B.A. in Graphic Communications, Nick also completed his massage therapy training at International Professional School of Bodywork in San Diego in 2014.

When he is not writing or reading, you would likely find him weightlifting at the gym, salsa dancing, or exploring new areas to walk and eat around Southern California.