MCL Injury: Causes, Symptoms, and Treatment
Medically reviewed by Sumiran Racherla, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats MCL Injury?
An orthopedist, a doctor who treats bone and joint problems, usually treats an MCL injury. A physical therapist, an expert in exercise and movement, often helps with recovery. Most people do not need surgery. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is an MCL injury?
The medial collateral ligament, or MCL, is on the inner side of the knee. It connects the femur (thighbone) to the tibia (shinbone). A ligament is a band of tissue that connects one bone to another. The MCL helps control side-to-side motion of the knee.
An MCL injury happens when this ligament is stretched or torn. It is one of the most common knee injuries. Doctors sort tears into three grades:
- Grade 1: the ligament is mildly damaged and slightly stretched. The knee stays stable.
- Grade 2: the ligament is stretched until it is loose. This is a partial tear.
- Grade 3: a complete tear. The knee is unstable.
Symptoms
Common signs of an MCL injury include:
- A loud pop when the injury happens.
- Pain on the inside of the knee.
- Swelling over the injury.
- Tenderness on the injured side of the knee.
- A feeling that the knee is giving out.
- Stiffness, or trouble fully straightening or bending the knee.
- Locking or catching of the knee with movement.
Causes and who gets it
The knee is not made to take forces from the side. An MCL injury is usually caused by a force that pushes the knee sideways and overstresses the ligament. This can be a direct hit or a sudden change in direction or speed.
Skiers and people who play cutting sports like basketball, football, or soccer are more likely to have this injury. Other risk factors are:
- High-contact sports.
- Sports with fast pivoting.
- Weak lower body strength.
- Past knee injuries.
Other parts of the knee may be hurt at the same time. Most severe MCL tears happen along with ACL tears. The ACL is another main knee ligament. A torn meniscus, a rubbery disk that cushions the knee, can also occur.
How doctors diagnose it
Your doctor will ask how the injury happened and what symptoms you have. The doctor checks your injured knee and compares it with your other knee. Most ligament injuries can be diagnosed with a careful physical exam.
The doctor will usually order imaging tests to confirm the diagnosis and rule out other injuries. X-rays do not show the ligament itself. They can show whether a piece of bone tore off with it. An MRI scan offers the best view of the injured ligament. An MRI machine takes special pictures of the tissues inside your knee.
Treatment
Treatment depends on how severe the injury is and whether other ligaments are hurt. A low-grade MCL injury with no related injuries can be treated without surgery. This focuses on:
- Rest, ice, compression, and medicines to reduce inflammation.
- A hinged knee brace for stability while you keep moving around.
- Crutches until the swelling and pain get better.
- Physical therapy to prevent stiffness and rebuild strength.
At home, rest your leg and ice your knee for 20 minutes at a time, 3 to 4 times a day. Wrap the ice in a clean cloth first. Wrap the knee with an elastic bandage, and raise your leg above the level of your heart.
Ibuprofen or naproxen can reduce pain and swelling. Acetaminophen helps with pain but not swelling. Talk with your provider before using these medicines if you have heart disease. Do not take more than the amount recommended on the bottle or by your provider.
Most people do not need surgery for an MCL injury. You may need it if your injuries are more severe and involve other ligaments. Once you regain motion and strength, your doctor may allow a gradual return to sports.
When to see a doctor
Contact your provider if you have increased swelling or pain, or if self-care does not seem to help.
Call 911 or go to the emergency room if you lose feeling in your foot, or if your foot or leg feels cold or changes color. These can be signs that blood flow or a nerve is hurt.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Either type of doctor can examine the knee, arrange imaging, refer you to an orthopedist, and follow your recovery.
Common questions
Does an MCL injury need surgery?
Most people do not need surgery for an MCL injury. Surgery may be needed if other ligaments in the knee are also injured.
What is the difference between an MCL and an LCL injury?
The MCL is on the inside of the knee, and the LCL is on the outside. The MCL is injured more often because the outer knee is more exposed to impact.
What are the grades of an MCL tear?
There are three grades. Grade 1 is a mild stretch, grade 2 is a partial tear, and grade 3 is a complete tear. Doctors use the grade to help plan treatment.
Can I play sports again after an MCL injury?
Yes, for most people, you can eventually play sports again. Your doctor may allow a gradual return once you regain your range of motion and strength.
Sources
- OrthoInfo (AAOS) - Collateral Ligament Injuries
- MedlinePlus - Collateral ligament (CL) injury - aftercare
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
