Medial Collateral Ligament (MCL) Injury: Symptoms and Causes
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Key Takeaways
- The medial collateral ligament (MCL) is one of four important ligaments connecting the thigh bone to the shin bone at the knee.
- An injury to the MCL is usually due to an injury caused by sudden movements that can damage the MCL itself.
What is the MCL?
The most discussed ligament in the knee is the anterior cruciate ligament (ACL), which is one of four key ligaments that connects your thigh bone (the femur) to the shin bone (the tibia). The medial collateral ligament (MCL) is also one of those four ligaments that not only connects these two bones, but also provides support to the knee joint. The MCL is located on the inner side of your knee on the side of the knee joint.
What is an MCL Injury?
An MCL injury happens when the ligament suffers damage. This may occur due to sports activities or a workplace injury where you make sudden movements or changes in direction that strains and injures the MCL, pushing the knee inwards towards the other knee.
Some common causes include:
- Direct impact on the outer side of the knee
- Lifting heavy items while in the wrong posture
- Suddenly slowing down, then changing direction or stopping
- Awkward landings from a jump or stumble
- Overstretching the knee
- Repeated stress on the knee
The last one is of particular importance. If you’ve had a previous injury and don’t let it heal properly, it can weaken significantly over time, making it easier to suffer an MCL injury later in life.
Elderly people are also at risk, especially if they may be frail or have underlying medical conditions that weakens their body. Even a fall from a short distance can potentially cause an MCL injury, which can exacerbate the risk of complications in the future.
Grades of MCL Injuries
There are three grades of MCL injuries, which indicate how severe the injury is:
The MCL is stretched or mildly torn, but apart from tenderness and mild pain, your knee can still bear weight
The MCL is partially torn, and your knee may feel “loose” if you move it with your hand. There may also be some (or a lot of) knee pain and tenderness on the inner side of your knee
The MCL is completely torn, and you’ll experience intense pain and/or tenderness; medical MCL treatment is urgently required. You may also have other related injuries, including to the ACL
Low-grade MCL injuries shouldn’t prevent you from walking, but you may still experience varying amounts of pain. Some people may not feel any pain at all, while others may feel some discomfort.
You should avoid self-diagnosing as only a thorough diagnosis, by an orthopaedic specialist, can determine the exact grade of the MCL injury and thus inform the nature of your treatment.
Symptoms of an MCL Injury
Some symptoms may be immediately apparent, especially for grade 2 or 3 injuries, while others may only arise much later. Symptoms include:
- Feeling or hearing a “pop” in the knee at the time of the injury
- Varying degrees of instability in the knee (as though it might give out)
- Swelling in the affected area within the first few hours of the injury
- Pain when moving the affected knee
- Stiffness in the knee
How are MCL Injuries Diagnosed?
A physical examination of the affected knee can help identify a possible MCL injury. Your doctor may massage the inside part of your knee to look for tender and/or painful areas. They may also examine the area where the MCL is to determine if it has been injured; you’ll experience pain and discomfort during the check, so be sure to let your doctor know about the intensity of pain at certain areas. There are also special tests that might be performed to determine the severity of the injury.
Sometimes called the medial stress test, it involves a series of movements to look for ligament injuries. You’ll be lying on your back while your doctor applies pressure to the outside of the knee while your leg is slightly raised. They may also repeat this procedure while your leg is straight. Your doctor will occasionally ask how you feel while applying pressure, so be sure to tell them exactly how you feel at that point in time.
If the knees open up more than they should, or if you experience a lot of pain, then it may indicate an MCL injury.
An imaging test may be ordered to confirm the doctor’s diagnosis and look for other complications. An X-ray may be needed to look for fractures or other injuries affecting the knee. An ultrasound or magnetic resonance imaging (MRI) test can provide detailed images of the soft tissues in the knee, including the MCL. This helps your doctor determine the severity of your injury along with any other damage to surrounding areas of the knee.
Learn more about the available treatment options for MCL tears in Singapore.
Orthopaedic Doctor for Knee Pain in Singapore
Dr. Ramesh Subramaniam
MBBS (NUS, SG) | MRCS (Edinburgh, UK) | M Med (Ortho) (NUS, SG) | FRCS (Ortho) (Edinburgh, UK)
Dr Ramesh, a fellowship-trained orthopaedic surgeon, focuses on shoulder, knee, and arthroscopic sports surgery.
Dr Ramesh obtained his MBBS and Master’s in Orthopaedic Surgery from the National University of Singapore and completed Advanced Surgical Training. He earned his Fellowship from the Royal College of Surgeons of Edinburgh in Trauma and Orthopaedics. He was awarded the HMDP scholarship for a clinical fellowship in Shoulder and Knee Surgery in Dublin, followed by the Tan Tock Seng Scholarship for a Sports Fellowship in Knee Surgery in Barcelona. He also completed a Shoulder Surgery Fellowship at Hospital Del Mar and was trained in arthroscopic joint reconstruction and joint replacement surgeries.
Are You or a Loved One Suffering from an MCL Injury?
Whether it’s a minor discomfort or a sudden, pressing issue, we at Avant Orthopaedics can help identify the cause of the pain and determine the most suitable course of treatment.
Frequently Asked Questions
Yes, they can. There are some instances where an injury to the MCL also causes a related injury to one of the other ligaments. MCL tears happen to be the most common one of the four.
Thankfully, they don’t. The MCL has a good blood supply that lets it heal very quickly, though it will still take between three to six weeks to make a complete recovery. However, in cases where you have other knee injuries along with an MCL injury, you may still need surgery to treat those injuries.
What you learn from your physiotherapy sessions can still play an important part in strengthening your body. Even once your MCL injury has healed, it’s a good idea to keep doing these exercises on a regular basis.
Related Conditions
Knee cartilage (also known as articular cartilage) is a strong, rubbery connective tissue that cushions and protects the bones of the knee joints. It also reduces friction by allowing the bones to slide smoothly against each other.
