Alternative Names MCL injury, medial knee ligament injury
Definition A medial collateral ligament (MCL) injury involves some degree of stretching of the main ligament on the inside of the knee.
The MCL is a broad band on the inside or medial side of the knee. The MCL runs from the just above the knee on the thighbone to just below the joint on the shinbone. This ligament provides the main source of stability for the inside of the knee joint. MCL injuries commonly occur when force is exerted on the outside of the knee that pushes the joint sideways. This places stress on the inside of the joint resulting in ligament damage.
There are three degrees of ligament injuries. A first-degree injury consists of only mild stretching of the ligament. There is no looseness of the joint. A second degree MCL is a partial tear of the ligament. In a third degree injury, the ligament is completely ruptured and the joint is unstable.
What are the signs and symptoms of the injury? A person with this type of injury will experience pain in the inside portion of the knee. The individual will still be able to walk almost normally if the ligament has been only mildly stretched. If there is a severe tear, the individual will not be able to walk or bear weight on the leg due to pain and instability of the joint. The amount of stiffness in the knee will depend on the amount of swelling. Bruising on the inside of the knee will be apparent when there is a partial or complete tear of the MCL. The area will be sore when pressed. Pain also occurs when stress is applied to the knee from the outer side.
What are the causes and risks of the injury? Most frequently the MCL is injured during sports when there is a twisting injury or blow to the outside of the knee. This might occur in a clipping injury in football or in a skiing accident if the knee is twisted.
Long-term effects of a MCL injury depend on the extent of the original damage and how well the knee heals. If the ligament remains loose, the knee will feel unstable. There will be a tendency for the joint to give way possibly leading to re-injury.
What can be done to prevent the injury? Many times, the injury cannot be prevented. However, a person should be in good shape and have good muscle strength before participating in sports. Sports safety guidelines should be followed for adults, adolescents, and children. Proper stretching exercises should be done before athletic activity. Ski bindings should be adjusted properly to prevent twisting.
How is the injury recognised? The doctor will usually diagnose an MCL injury based on a physical examination and the person's description of the injury. Joint x-rays of the knee are also commonly performed. Most of the time, the bones appear normal. A special x-ray called an MRI is sometimes done to show the extent and location of the MCL damage and to look for other injuries.
What are the treatments for the injury? Treatment for MCL injuries depends on a number of factors including:
the degree of MCL injury
the person's age and future activities
other injuries that may have occurred at the same time
The first step in treatment is the RICE method. This stands for rest, ice, compression with an elastic bandage and elevation of the leg. Medications, such as non-steroidal anti-inflammatory medications (NSAIDs), can help reduce pain. More painful injuries or those where the knee is unstable may require a splint or brace to immobilise the knee and crutches. After an initial period of RICE, physiotherapy is started. This is aimed at restoring the range of motion in the knee joint and increasing strength in the thigh muscle. The majority of MCL injuries will heal successfully without surgery. Cases in which the ligament has been completely torn and the knee is unstable may require surgery. Sometimes a special brace that allows knee movement while avoiding tension on the ligament is useful while the injury is healing.
What are the side effects of the treatments? All medications have side effects, including allergic reactions. Long-term use of NSAIDs may harm the stomach, kidneys, or liver. The knee can become stiff if it is immobilised for too long. Surgery carries a risk of bleeding, infection and reaction to the anaesthesia.
What happens after treatment for the injury? If the ligament does not heal properly, the knee may not regain its original stability. If healing and physiotherapy go well, the person can often return to normal activities.
The doctor will check the flexibility and strength of the knee and assess the stability of the joint.
Author: John A.K. Davies, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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