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MCL Knee Ligament Injury Explained

The Medial Collateral Ligament is the knee ligament located on the inside of the knee joint. It links the thigh bone and the shin bone. Any knee injury involving ligaments is referred to as a sprain, and is a relatively common knee injury that can occur when the knee is twisted or subject to external force for example from an opponent during contact sport, depending on the severity of the injury it is classified as first, second or third degree:

  • A first degree sprain - damage to only a small number of ligament fibres.
  • A second degree sprain - damage to an extensive number of ligament fibres, however, the ligament remains intact.
  • A third degree sprain - complete rupture of the ligament.

MCL injuries are classically caused in one of two ways. When playing contact sports such as American football or rugby, or in sports where collisions are likely such as football, the Medial ligament can be damaged when force is applied during impact, usually impact between the knees of one player with to the leg just above the knee of another. The other common injury type occurs when the players studs get caught in turf and they try to turn to the side, away from the planted leg causing over extension and possible tearing of the Medial Collateral Ligament. When a complete rupture occurs, the force involved to cause this injury can also cause damage to other structures in the knee, such as the Meniscus (Cartilage) or the Anterior Cruciate Ligament.

Signs & Symptoms

A person suffering from a first degree sprain of the Medial ligament will experience pain when touching site of the damage is touched. When the knee is slightly bent and the shin is twisted inwards causing stressing the injury and causing pain, this action is reproduced when standing up out of a chair. Second degree sprains, cause more severe pain when touched and when the ligament is stressed. There will usually be a swelling of the knee joint, however, the swelling may take 24hours to show. In the case of a third degree sprain, where the ligament is ruptured, the knee joint is unstable and activity cannot be continued.


In the initial stage of all three levels of injury medication prescribed by a doctor for pain relief should be taken if necessary. The PRICE protocol should be followed - Protection, Rest, Ice, Compression and Elevation (never apply ice directly to the skin). The knee should be rested in an elevated position and Cohesive Bandage (which sticks to itself) makes for a suitable compression bandage to help prevent excessive swelling. Ice Packs applied for twenty minutes, every two hours, can aid pain relief and help to prevent more tissue damage by cooling the tissues. In the case of a first degree sprain, you should rest the leg and stop sporting activities for approximately three weeks. For second degree sprains, the rehabilitation period will be between 6 and 8 weeks. Rehabilitation under the supervision of a chartered physiotherapist is desirable to prevent a recurrence of the injury, which can be common if a return to sport is attempted too early. In the case of a third degree sprain, where the ligament is completely ruptured, the treatment of choice is surgery to repair the structure. The type of reconstruction used will depend on the exact site of the damage and the preference of the surgeon. Many people find that using a Knee Brace can be very helpful if they have suffered a Medial Collateral Ligament injury. The brace supports the knee and takes the strain off the ligament during the early stage of injury. The knee brace also provides protection during the later stages of rehabilitation. Running in a swimming pool, using a Buoyancy Aid, is an ideal method of maintaining fitness while the ligament is healing. The Donjoy Armor is a particularly good brace for this purpose.

Injury Prevention

You can't do a lot if a prop forward (in rugby) or a centre half (in football) decides to throw their weight against your knee. Passing the ball earlier is probably the best advice that can be given. In the case of someone who has had a previous Medial Ligament injury there may be a slight weakness, but there are measures that can be taken to help prevent a recurrence. A Knee Brace can provide increased knee stability and reassurance following previous knee injuries, especially during activities such as skiing.