There are four main ligaments in the knee - one on either side of the knee joint (the medial and lateral collateral ligaments) and two criss-crossing in the middle (the cruciate ligaments).
These bands of fibrous tissue may be damaged when excessive or sudden strain is put on the knees. Ligament injuries in the knee are common among sportspeople, especially in football, rugby, skiing, netball and basketball for example, where suddenly jumping, turning or twisting movements are common, or there is a sudden change in direction.
The extent of a ligament injury is usually graded:
Grade 1: A sprain with no tearing of the ligament
Grade 2: A partial tear
Grade 3: A complete tear
The medial collateral ligament is strong but most likely to be damaged if the leg is twisted and knocked sideways while in a straightened position. The lateral collateral ligament is less often damaged. Anterior cruciate ligament strains or tears are the most common knee ligament injuries, and usually occur as a result of lateral rotational movements. Injury to the posterior cruciate ligament is sometimes called the 'dashboard injury' because it often occurs when someone hits the dashboard of a car during an accident (this is often how it occurs).
Symptoms Of Knee Injuries
Typical symptoms may include:
Instability - you may feel like your knee is giving way or that it's locking, or that you can’t stand on it. A popping or snapping sensation at the time of the injury, or even hear a popping sound Ligaments hold the knee joint closely together, limiting the amount it can move from side to side. So an injury can make the joint feel wobbly and unsteady.
However after a partial tear of a collateral ligament, the knee may still feel fairly stable because this ligament consists of many minor ligaments in different directions and layers, which mesh together into one single strong ligament. The cruciate ligaments particularly provide stability in the forward and backward movements of the knee joint. Damage to these ligaments may leave the knee unstable in these directions.
Treatment Of Knee Injuries
Following an injury you should follow the 'PRICE' advice:
Protection: protect your knee from further harm
Rest: rest for two to three days then gradually re-introduce exercise
Ice: apply an ice pack (or bag of frozen peas wrapped in a tea towel) immediately to the injury to reduce swelling and pain.
Compression: wrap the knee in an elastic bandage to support the joint and reduce swelling
Elevate: rest the leg up on a chair
You can also take simple painkillers to mange the pain and, with ibuprofen, help to reduce inflammation.
Many minor strains should settle with these steps. However, in more severe injuries or if the symptoms persist you may need specialist advice. MRI or ultrasound scans may help to assess the problem and the extent of damage.
A physiotherapist can offer you treatment to speed healing and exercises to strengthen the joint and its muscles and ligaments. In severe cases surgery may be necessary to repair the injury and make the joint stable again. Cruciate ligament injuries are more likely to need surgery.