What is an MCL Injury?
The knee is comprised of four major ligaments, all of which connect the thigh bone (femur) to the shin bone (tibia). The Anterior Cruciate Ligament (ACL) and the Posterior Cruciate Ligament (PCL) are arranged like an “X” in the middle of the knee. The Medial Collateral Ligament (MCL) lies on the inside of the knee, while the Lateral Collateral Ligament (LCL) is on the outside of the knee.
The MCL prevents the knee from going inward (or into valgus), as when a football player is tackled from the outside. In an MCL tear, the ligament fibers tear partially or completely. The MCL most commonly tears away from its attachment to the femur. Tears are graded on a 1-3 scale with 1 being only a mild tear and 3 being a severe tear. MCL tears cause severe pain, usually being more painful than after an ACL tear. The knee can feel unstable, like it wants to buckle inward when rotating on the knee. An MCL injury usually requires orthopedic attention in order to determine the grade of injury, to rule out further injury, to be fit for knee brace, and to be educated on the recovery process. Dr. Cunningham is a knee specialist at Vail Summit Orthopedics and Neurosurgery. He is an expert at diagnosing and treating MCL tears for patients in Vail, Summit County, Aspen, and Denver, CO.
What Causes a Torn MCL?
A torn MCL is almost always due to a traumatic event, such as a hard fall or an injury while playing sports. As the knee angles inward, the MCL is stretched until its fibers tear to varying degrees. Patients often report hearing a pop and then having severe pain. The knee can feel unstable to walk on following an MCL tear.
What Does Torn MCL Feel Like?
Patients have immediate pain located on the inside of the knee. An audible popping sound may occur upon injury. This popping is the sound of the ligament tearing.
Additional symptoms may include:
- Stiffness and tightness in the knee
- Difficulty straightening and bending the knee
- Swelling and pain localized to the inside of the knee
- Difficulty going up and down stairs or getting up from a seated position
- Sensation of the knee giving way, especially when turning on the knee
MCL tears are often isolated injuries. However, it is not uncommon to tear other ligaments in the knee at the same time, such as tearing the ACL.
How to Diagnose a Torn MCL
The pain, swelling, and feelings of instability after suffering an MCL tear usually leads a patient to seek medical attention right away. Dr. Cunningham will take a history of how the injury occurred and then perform a thorough physical exam. The attachment sites of the MCL will be palpated, as one will be tender over one or both of these sites if the MCL has torn. The knee is gently stressed to determine if the MCL is lax, consistent with a tear, and during this testing, the severity or grade of the tear is determined. The knee is also examined for any other associated ligament tears in the knee. In addition to examining the injured knee, it is important for your orthopedic doctor to examine your normal knee, as this provides a good comparison of how tight the ligaments normally are, as some people have loose ligaments normally while others have tight ligaments normally. Testing for a medial meniscus tear is also performed, as the painful areas after a torn MCL overlap with the painful areas after a medial meniscus tear. However, there is no ligament laxity in someone with an isolated medial meniscus tear.
MCL tears, like all ligament tears, are graded as follows:
- Grade I: The MCL has been stretched, and a small number of its fibers are torn. There is mild medial joint opening (1-5mm) when the MCL is stressed on a physical exam.
- Grade II: The MCL has partially torn. There is moderate medial joint opening (6-10mm) when the MCL is stressed on a physical exam.
- Grade III: The MCL is completely torn. There is severe medial joint opening (greater than 10mm) when the MCL is stressed on a physical exam.
Diagnostic imaging is usually ordered to complete the evaluation and make the proper diagnosis. X-rays provide insight on the condition of the bones, as sometimes an MCL tear results in a portion of the bone pulling away. Magnetic resonance imaging (MRI) may be ordered to further study the location and degree of MCL tearing, as well as rule out other associated tears, such as injury to the ACL or meniscus.
Does an MCL Tear Require Surgery?
Most often, non-surgical treatments are recommended for the initial care of an MCL tear. The majority of MCL tears heal in a hinged knee brace worn for approximately 6 weeks. Other recommended treatments include:
- Rest, ice, elevation, and compression for the first few days after injury.
- Pain medications such as Tylenol if needed.
- Physical Therapy to help restore range of motion and to maintain strength
- Avoiding cutting and pivoting sports until the ligament has fully healed and you have been cleared to undertake these activities.
Unfortunately, some types of MCL tears are known to not heal well. These tears include MCL tears where the MCL fibers pull away from their tibial attachment. Tears from the femur attachment have a better chance of healing than tibial tears. Thus, MCL tears from the tibial attachment, which are commonly retracted, do better with surgery done soon after the injury. In surgery, the torn MCL is stretched and secured back to its normal tibial attachment site. Furthermore, many Grade 3 MCL tears only heal partially. If, after 6-8 weeks of wearing a hinged brace, a grade 3 tear is only healed to a grade 2 tear, surgery may then be recommended, especially if one wishes to resume cutting and pivoting sports or if you feel unstable with everyday activities such as walking. Finally, if multiple ligaments are torn in the knee including the MCL, then the MCL is better treated with surgical repair or reconstruction.
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What is the Recovery Like After an MCL Injury?
Patients with an MCL tear are usually placed in a hinged brace. For Grade 1 MCL tears, a small, over the counter brace is sufficient. For Grade 3 MCL tears, a large, special hinged brace is recommended. A knee brace is worn for 2-4 weeks in Grade 1 tears, 6 weeks for Grade 2 tears, and 6-8 weeks for Grade 3 tears. At the end of one’s bracing period, the knee should be re-examined by your orthopedist to determine if the MCL has healed well in the brace.
For patients who require MCL surgery, some tear patterns are amenable to simply stretching the torn and retracted MCL back to its normal attachment site and securing it in place. However, more often an MCL reconstruction is indicated. In this surgery, a donor tendon is used to reinforce your stretched out MCL, sewing the donor tendon into your injured MCL and fixating the donor tendon to the normal MCL attachment sites on the femur and the tibia. Patients go home the same day in a hinged brace. Range of motion exercises can be started immediately. However, no weight bearing is allowed for 4 weeks, as this stresses the MCL reconstruction. At 4 weeks, partial weight bearing is started and one can bear full weight at 6 weeks after MCL reconstruction surgery. Physical therapy is prescribed after surgery, with one going 2 times per week for 2-3 months. By 8 weeks from surgery, one can ride on a bike outdoors. By 10-12 weeks, one can run. Most patients are able to return to full activities, including cutting and pivoting sports, by 12-14 weeks. A sports knee brace may be recommended to help prevent reinjury, once cleared for high level athletics. Dr. Cunningham is a knee specialist at Vail Summit Orthopedics and Neurosurgery. He is an expert at diagnosing and treating MCL tears for patients in Vail, Summit County, Aspen, and Denver, CO.
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Dr. Cunningham specializes in the treatment of knee, shoulder, and sports injuries.