Inner Knee Pain While Running? Could Be A MCL Sprain

MCL sprain is a common knee injury, especially among runners. Learn what to do if you have one and when you can return to play.  


What is MCL?

MCL (medial collateral ligament) is a thick band of elastic tissue on the inner side of the MCL Sprain knee. It connects the thigh bone and the shin bone. The primary functions of MCL are: (1)

  • Preventing knee hyperextension
  • Stabilizing the knee 
  • Helping you sense the knee joint position (even when your eyes are closed)


What is MCL Sprain?

MCL sprain happens when the medial collateral ligament is overstretched or torn. It is the most prevalent knee ligament injury, accounting for over 40% of all cases. 

MCL injuries affect more than 70,000 people in the US each year. (2) Most MCL sprains are isolated injuries; however, they may occur with another type of knee ligament injury, like an ACL (anterior cruciate ligament) tear. 

Further Reading: What Is The Torn ACL In Knee? 

The majority of people heal with conservative treatment, while those with severe injuries may require surgery. Likewise, an MCL sprain, in extreme cases, may lead to chronic knee instability. 


Who is At Risk?

The risk appears higher in males. In fact, males are twice as likely as females to present with an MCL injury. Likewise, it is usually diagnosed in participants of contact sports (soccer and football) or sports that require players to rotate their knees, such as skiing and ice skating. For example, 6 in 10 skiing knee injuries involve the MCL. (3)


What Causes MCL Sprain?

Any blow to the outside of the knee or abrupt twisting/turning of the knee can cause an MCL sprain. For instance, an MCL injury can occur when a footballer is hit on the outside of the knee by a tackler. Other situations can include:

  • Cutting; a player plants one foot into the ground and changes direction quickly
  • Heavy squatting
  • Landing badly after a jump
  • Overstretching the knee
  • Repeated pressure to your knee, resulting in less elastic MCL


MCL Sprain Symptoms

When you have an MCL sprain, you will most likely experience:

Pain:  Inner knee pain is usually what most people report, typically following a sporting event. It may be mild or severe. 

Swelling: Along with pain, you may have a swollen knee, which means your immune system is working to prevent further damage. Swelling is often present with stiffness. 

Tenderness: You may feel pain along the inner edge of the knee upon touching or applying pressure. 

Knee instability: You may find it difficult to stand or walk, as your knee is unable to bear your weight. 

Knee locking: Knee locking is when you feel like you cannot move your knee because of anticipated pain and discomfort. 

Occasionally, some people may hear or feel a pop during the impact. 


How is MCL Sprain  Diagnosed?

Diagnosis involves a physical exam and tests. Besides, your healthcare provider will Recovery time for ACL surgery usually ask the following questions:

  • When did you start feeling the pain?
  • How severe is your pain?
  • Does walking or moving your knee cause or worsen the pain?
  • Did you hear or feel a pop during the impact?

Be mindful of how you answer the questions. Doing so will promote accurate diagnosis and better treatment outcomes. 

Then, they will check your knee to see how badly it has been hurt. They will likely press the inside and outside of the knee (both straight and bent) to determine joint stability. 

Furthermore, they may order the following imaging tests:

    • X-rays. They don’t show your MCL, but they will help check if you have a fractured bone. 
  • MRI. MRI or magnetic resonance imaging is highly accurate in ruling out other associated conditions, such as a torn ACL or meniscus tear.  
  • Stress X-ray. They are useful in grading the MCL injury. 


MCL Sprain Categories

After a careful evaluation of findings from the physical exam and imaging test, your provider will grade your injuries into one of the following categories:

  • Grade 1 sprain: Only a few (< 10%) torn fibers in your ligament, stable knee, mild pain, little to no swelling. 
  • Grade 2 sprain: Partial ligament tearing, intense pain and swelling, stiffness, knee instability. 
  • Grade 3 sprain: Severe ligament tearing, severe pain and tenderness, unstable and loose knee. 


MCL Sprain Treatment 

Treatment depends on the category of your injury. For example, Grade 1 and 2 MCL sprains are usually treated nonoperatively. Nowadays, surgery is rarely used, even for Grade 3 sprain. 

Early treatment

The medial collateral ligament regenerates fast and has a rich blood supply. Thus, the treatment uses the P.R.I.C.E. method. 

  • Protection. It aims to avoid further injury by protecting the damaged structures. You may use an ace bandage, aluminum splint, sling, protective tape, or over-the-counter brace.
  • Rest. Avoid physical activities that put a lot of stress on your knee. In addition, you may use an over-the-counter (OTC) pain medication to ease pain and reduce swelling. 
  • Ice. Cold temperatures can help reduce pain and swelling. Wrap ice in a damp towel and apply it to your knee for about 15 minutes at a time, several times a day.
  • Compression. Wrap your knee with an elastic bandage to reduce swelling and support your knee. 
  • Elevation. Rest the injured knee above the level of the heart as often as possible. To do so, lay on your back and rest your leg on a pillow.


If you need to walk with an MCL injury, you will need a crutch. Crutches help reduce stress on your knee by transferring your weight to other body parts. Grade 1 and 2 sprains require you to use a crutch for only a few days. 

On the other hand, if you have a Grade 3 injury, you will need them for about 2 weeks. 


Physical therapy exercises help you regain strength and range of motion. Examples include: (5)

  • Knee flexion with heel slide
  • Heel slides on a wall
  • Quad sets
  • Short-arc quad
  • Straight-leg raises 
  • Hamstring set
  • Lateral step-up



Surgery For MCL Sprain

Surgery to repair an MCL tear is rarely used these days. However, you may need it if you have associated knee injuries or persistent knee instability. For instance, surgery might be an option if you have combined ACL and MCL knee injuries. 

Further Reading: How To Get A Second Opinion For Surgery


MCL Sprain Recovery Time

Thanks to the ability of the MCL to regenerate fast, most MCL injuries heal well with proper treatment, and complications rarely occur. 

Grade 1 and 2 injuries allow return to full pre-injury activities by 12 weeks. Likewise, if you have a grade 3 injury, you can expect complete recovery by 6 to 9 months.

Return to Play

The time for return to play is sport-specific; below is a general guideline. (6)

  • Grade 1 and 2 sprains: 1 to 4 weeks from injury. 
  • Grade 3 sprain not requiring surgery: 5 to 7 weeks from injury. 
  • Grade 3 sprain treated with surgery: 6 to 9 months from surgery. 



Question: Where is MCL?

Answer: MCL (medial collateral ligament) is located on the inner side of the knee. 


Question: MCL sprain vs. tear: What’s the difference?

Answer: MCL sprain includes knee injuries that either overstretch or tear the MCL. MCL tear is either a grade 2 or grade 3 injury, which is usually considered severe. 


Question: How long does an MCL sprain take to heal?

Answer: Healing from an MCL sprain can take from a few weeks to 9 months. The time to recover depends on the category of the sprain and whether you need surgery. 


Question: What does an MCL sprain feel like?

Answer: MCL sprain causes knee pain, tenderness, swelling, and knee instability. 


Question: Can you still walk with a sprained MCL?

Answer: You may be able to walk with a grade 1 sprain; however, it can cause pain. Moreover, walking when you have an injury is not recommended. 


Question: How serious is an MCL sprain?

Answer: MCL sprain is usually mild and improves with conservative treatment. Complications are rare, and surgery is not routinely used. 


Question:  Can I prevent an MCL sprain?

Answer: Consider the following tips to prevent MCL sprain:

  • Warm up before exercising.
  • Strengthen the muscles around your knees.
  • Wear well-fitting shoes. 
  • Wear braces. 


Can Telemedicine Help?

Telemedicine is gaining popularity because it can help bring you and the doctor together quicker and more efficiently. It is particularly well suited for sports injuries and facilitating the diagnoses and treatment of those injuries.  Learn more about  speaking with a sports specialized provider via SportsMD’s 24/7 Telemedicine Service.




  1. National Library of Medicine. Anatomy, Bony Pelvis and Lower Limb, Knee Medial Collateral Ligament. Accessed 23 January 2023.
  2. Schein, Aaron et al. “Structure and function, injury, pathology, and treatment of the medial collateral ligament of the knee.” Emergency radiology vol. 19,6 (2012): 489-98. doi:10.1007/s10140-012-1062-z
  3. National Library of Medicine. Medial Collateral Ligament Knee Injuries. Accessed 23 January 2023.
  4. Roach, Christopher J et al. “The epidemiology of medial collateral ligament sprains in young athletes.” The American journal of sports medicine vol. 42,5 (2014): 1103-9. doi:10.1177/0363546514524524
  5. Medial Collateral Ligament Sprain: Rehab Exercises. Accessed 23 January 2023. 
  6. Kim, Christopher et al. “Return to Play After Medial Collateral Ligament Injury.” Clinics in sports medicine vol. 35,4 (2016): 679-96. doi:10.1016/j.csm.2016.05.011


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