The medial and lateral collateral ligaments of the knee are found on the sides of the knee. They connect the thighbones to the lower leg bones and control sideway movements of the knee. The MCL plays an important role in limiting and maintaining knee joint movements and protecting stability along with the adjacent muscles.
What causes an MCL injury?
The MCL is the most commonly injured ligament in the knee caused by direct contact with the knee. It is often injured along with injury to the anterior cruciate ligament. Injury to the MCL is the single most common traumatic injury in football. However, ice hockey, skiing, soccer, wrestling, judo and rugby are also sports in which the MCL is injured. Males are at greater risk than females. Injuries to the MCL account for 40% of all severe knee injuries, and often involve a fracture.
MCL injury grading and symptoms
MCL injuries are graded on a scale from 1 (least severe) to 3 (most severe):
- Grade 1 –The ligament has sustained mild damage but can still function. Symptoms include tenderness and minor pain.
- Grade 2 – The ligament is stretched and has become loose. It is also called a partial tear. Symptoms include significant pain, tenderness and swelling on the inside of the knee.
- Grade 3 – The ligament is split or pulled off the bone. Symptoms include substantial pain and tenderness on the inside of the knee, swelling and noticeable joint instability. 80% of grade 3 MCL tears are associated with injury to the anterior cruciate ligament (ACL).
Dr. Cooper will ask about how the injury occurred and your symptoms. He will conduct a physical examination testing range of motion and other specific tests of knee stability, feel for swelling and tenderness and order imaging tests to confirm a suspected diagnosis. An x-ray may be ordered to rule out a fracture. An MRI will be recommended to identify the location of a tear and the extent of damage to the MCL and other knee structures and ligaments.
Treatment options for an MCL injury depend upon the severity of the injury. Isolated Grade one and two MCL injuries are typically treated with conservative, non-surgical measures including rest, ice, compression, elevation and anti-inflammatory medications coupled with progressive physical therapy once the swelling and pain improve, and possibly a stabilizing knee brace to prevent side to side knee movements. A minor injury can heal with conservative measures in a few weeks.
In isolation, grade 3 injuries can often be treated conservatively with bracing and physical therapy. However, occasionally patients have continued instability after non-operative treatment, and require surgery. Additionally, when in combination with other ligamentous injuries about the knee, MCL tears can benefit from surgical treatment, Grade 3 injuries without surgery can take 4-8 weeks to heal.
When surgery is needed because of the location of the tear, the ligament is torn away from the bone, is torn in the middle or the injury involves damage to other knee ligaments, Dr. Cooper will repair or reconstruct the ligaments, or reattach the ligament to the bone with stitches, screws or staples or sew together the torn edges.
MCL ligament reconstruction surgery is reserved for patients with severe ligament tears that fail to heal and suffer chronic instability. When the ACL requires reconstruction, the MCL will also be reconstructed to prevent overload on the ACL. The choice of graft will be determined by Dr. Cooper.