What is the MCL?
MCL stands for Medial Collateral Ligament. It is the major ligament on the inside (medial) part of the knee. If you put your finger on your kneecap then slide the finger over towards the inside of your knee, you will land on the MCL. It is one of two collateral ligaments in the knee. The other being the Lateral Collateral Ligament, which I will discuss in the future.
The MCL runs from the end of the thigh bone (femur) down to the shin bone (tibia) on the inside part of the knee. It is a broad strap of tissue that is the main stabilizer of the inside part of the knee. It prevents what we call valgus for at the knee. A valgus force is basically anything that makes the knee move inward towards the other knee. Take a look at the image below to get an idea of where the MCL lives. The image is of a Right Knee.
How is it Injured?
Now that we have an idea of what it is, lets discuss how it can be injured. The overwhelming majority of the injuries will be caused by someone or something pushing on the outside (lateral) part of the knee and forcing it inward. If the force is too great, the MCL will be injured. There will be pain on the inside of the knee and potentially a pop. MCL injuries like this are quite common in football and soccer. Just think about how many bodies are falling and rolling around knees in any given football play. This is why you see most offensive lineman in college and the pros wearing knee braces. The braces are designed to prevent the knee from going too far inward if a player does fall on the outside of their knee thus lowering the chances of an injury to the MCL. Slide tackles in soccer can cause the injury as well.
There are other ways to injure the MCL like hyperextending the knee or a hard twist with the foot planted in the ground, but those are less common ways to injure it compared to another player causing the injury as described above.
How Do I Know How Bad the Injury Is?
Just like most things in life, there are varying degrees of an MCL injury. It is a very simplistic grading system from 1 to 3. 1 is not so bad, and 3 is bad to keep it simple. I will break the grades down a bit more below:
*Grade 1 - this is what we would call a mild sprain. The fibers of the ligament have been stretched just a little bit to cause discomfort, but there is not a huge injury to the ligament. There will be pain if you touch the area and with walking, but it will not be greatly limiting to do normal tasks. With proper rest and ice Grade 1 injuries can around a week to heal, but recovery times to vary.
*Grade 2 - this is where we start to see some tearing of the ligament. The force on the knee was great enough to tear through probably about half of the fibers of the ligament but not all of them. These are much more painful and limiting. There will be swelling and instability of the knee. A brace or crutches may be needed to get around. This will be a much longer recovery. Generally speaking, you are looking at 4-6 weeks to be back to normal. Proper physical therapy will be needed to restore motion and strength.
*Grade 3 - there will be complete tearing of the ligament with this injury. The pain and swelling will be a bit worse than the Grade 2 injury, but the most problematic thing with Grade 3 injuries is the instability of the knee. With the ligament completely torn, the medial (inside) part of the knee has nothing to be a restraint for motion. We hope with these that the body can produce enough scar around the injured ligament to give the knee some stability. Crutches and a brace will be used here to allow the ligament to heal along with consistent physical therapy and treatment. I think you are looking at a minimum of 6 weeks to recover but most likely longer. Surgery to repair the ligament could be considered if the stability of the ligament does not return to a satisfactory level.
How Does Your Healthcare Provider Determine the Severity?
There are a number of things that will lead your provider to grade the injury. How it was injured, swelling, stiffness, ability to walk on it, but the main determining factor will be how loose the ligament is. It's called testing the laxity of the ligament. He or she will stress the ligament by pushing on the outside of the knee to determine how stretched or torn the ligament is.
An MRI is not always needed with an MCL injury, especially for grade 1 or 2 injuries. With bad grade 2 or 3 injuries, the athlete may not let anyone do a physical exam on the knee because of pain and stiffness. An MRI may be ordered in this situation to see the extent of the damage to the knee. Also with higher grade injuries, there are commonly other injuries in the knee (meniscus, acl, etc) that an MRI could find as well.
Take Aways......
The biggest take away in regard to an MCL injury is that the majority of them heal on their own with time and will not need surgery. It is a set back and could take a good amount of time to heal, but it's not like its cousin the ACL that requires surgery most of the time when it is injured. If the injury is protected properly and treated the right way, your kid will most likely be back to normal before his or her season is done.
Hunter Greene, MS, ATC, OPA-C
**Disclaimer: Please consult with a local healthcare professional for definitive diagnosis and treatment. This information should not be used to diagnose and treat injuries.
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