*For a description of ligaments of the knee, see the blog entitled “The Knee Explained”. The medial collateral (MCL) and lateral collateral ligaments (LCL) are tough fibrous material that connects the femur to the tibia (MCL) and fibula (LCL). They are support ligaments that help prevent excessive medial and lateral movement. The MCL is located on the inside of the knee and the LCL is on the outside of the knee.
CAUSES: The MCL is sprained more often than the LCL. The MCL is usually injured when there is a blow to the outside of the knee causing excessive motion to the inside of the knee. Chronic MCL pain can result from flat feet, poor joint alignment, and even hip problems. LCL sprains are far less common and usually result from a blow to the inside of the knee which forces excessive stretching of the outside part of the knee.
SIGNS/SYMPTOMS: Signs and symptoms correlate to the extent of injury. Grade I tears are mild with only some fibers torn. Grade II tears are also considered partial because this involves approximately ½ of the ligament fibers. Grade III tears are complete tears of all the ligament fibers. Signs and symptoms include pain over the ligament site, swelling, possible bruising, and in more severe sprains, instability.
DIAGNOSIS: Done by physical exam, history of the injury, and MRI to see the extent of the damage.
TREATMENT: Rest, ice (about 15 minutes at a time), compression, and elevation (RICE), physical therapy, adjustment of the knee to align the joint for proper healing, bracing for support, and rarely surgery in more severe cases. Sprains to these ligaments are treated more conservatively because unlike the ACL, they have a direct blood supply which helps with healing.
COMPLICATIONS: Poor rehabilitation of the knee can result in excessive scar tissue formation and loss of normal function and movement of the knee. Future arthritis may also develop if the knee is not properly lined up when it is healing. Also, many times there are other injuries in addition to a collateral ligament sprain that need to be dealt with.
PROGNOSIS: Very good. These ligaments tend to heal themselves and so with proper rehab and treatment, people with collateral ligament injuries tend to recover and go back to their respective activities in anywhere from 1 to 12 weeks depending on the severity.