Anatomy of the MCL
The medial collateral ligament, or MCL, is located on the inside of one’s knee. It is a very strong ligament that prevents one’s knee from swinging to the outside against any forces on the knee. MCL tears are quite frequent, especially in skiing, and occur more than twice as often as ACL tears.
The MCL is located outside the joint itself, which means it is surrounded by a really good blood supply and has a good chance of healing. It attaches both to the thigh bone (femur) and shin bone (tibia). The most common place that an MCL tears is off the thigh bone, which is good because this is where a large number of stem cells for healing are located.
How to Diagnose an MCL Injury
When one does suspect that they have torn their MCL, they should have a physical exam to verify this. In addition, x-rays may be indicated, especially stress x-rays if one is concerned that there is some gapping present. In teenagers who may be growing, they may actually have a fracture through the growth plate rather than an actual MCL tear and it is important to differentiate this because the treatment obviously is different between a fracture and a ligament tear. MCL tears are usually “graded”. For those tears in which it is painful over the MCL, but there is no gapping on exam, we assign them a grade of 1. For those MCL tears where there is pain and some mild gapping, we call a grade 2. For those tears in which there is significant pain and the knee gaps open without it seeming like there is any ligament to prevent it from opening, we call a grade 3. A physical exam is usually very good at helping to differentiate the grading of an MCL tear, whereas an MRI scan is most useful to determine if there are any other associate injuries present. This is especially important if one has swelling within their knee, which could indicate a kneecap dislocation, ACL tear, or a meniscus tear.
Treatment Options for MCL Tears
The treatment of an MCL tear depends both on its grade and whether there are other injuries present with the MCL tear. Grade 1 and 2 MCL tears where there are no other concurrent injuries, as well as most grade 3 tears, can be treated with a well-guided therapy program to return one to activities sooner. In patients with significant gapping, an ACL type brace may allow one to both get back to activities sooner and minimize the risk of having the tear not heal correctly.
Most nonoperative treatment of MCL tears centers around trying to decrease swelling, restoring one’s knee motion, and trying to get one’s muscle strength back. The most useful exercise is the use of a stationary bike because the spinning on a bike helps to align the new forming collagen fibers into better position and can also help restore one’s motion and strength more quickly. Therefore, we will get patients with an MCL tear on a stationary bike as soon as possible to help them heal faster.
MCL Tears with Other Ligament Tears
When an MCL tear happens with another knee ligament injury, or a meniscus tear, one may require surgery. In cases where there are more ligaments involved, which may be a knee dislocation, or where the MCL is stripped back off the tibia or when one’s knee opens up on physical exam when it is out straight, surgery is almost always indicated.
The most common injury pattern with an MCL tear is to have it happen with an ACL tear. In this circumstance, most MCL tears heal and then the ACL can be reconstructed. As mentioned above, those knees who gap open when one has the knee out straight or who have the MCL stripped off the tibia almost always need surgery and these patients should undergo a combined ACL and MCL reconstruction sooner rather than later. In most patients where the MCL is torn off the femur or in grade 1 or 2 MCL injuries, one can start with a physical therapy regimen and then proceed to an ACL reconstruction once the ligament is healed sufficiently or once the patient’s knee motion has returned back to normal.
When to Have MCL Surgery
When one does need to go to surgery, recent peer-review publications have indicated that reconstructions do better than repairs because repairs have a problem with both having the repairs stretch out and also having a higher risk of the knee getting stiff with repairs and requiring a second surgery. Therefore, many sports medicine physicians these days will have the patient start physical therapy immediately after an MCL reconstruction to minimize the risk of the knee getting stiff. Our research team has invented several MCL reconstruction techniques, which have been proven to be quite successful and are considered to be the “gold standard” treatment for many types of MCL tears.
Any patient who undergoes a MCL surgery should plan on following a well-developed and structured rehabilitation program. The newer MCL reconstruction techniques that we have developed are extremely successful, but it is also important to recognize that they need to be combined with physical therapy regimens to ensure restoration of one’s motion and overall strength. Coupled with this, we often recommend that the patient/athlete wear a protective knee brace through the first competitive season to minimize the risk of extra stress on an MCL reconstruction.
In summary, MCL tears are quite common and often can be treated without surgery. However, some particular types of MCL tears have a low chance of healing and these should be diagnosed soon after injury to give the patient their best chance of getting back to full activities.