Knee ligament tears - Knee Injuries

The knee is supported by four main ligaments; these are the anterior cruciate ligament, the posterior cruciate ligament, the medial collateral ligament and the lateral medial ligament. The cruciate ligaments are located inside the joint, while the collateral ligaments run along the outside of the knee (the lateral runs along the outer side, while the medial runs along the inner side). These ligaments support the knee during movement and allow flexibility around the joint. The cruciate ligaments prevent the tibia from falling forwards (anterior cruciate ligament) or backwards (posterior cruciate ligament) onto the thigh bone (femur). The collateral ligaments support the sides of the knee.

Types of ligament tear

  • ACL tear (anterior cruciate ligament): this is a common sporting injury, which is usually caused by an action which causes the knee to twist. The medial collateral ligament is also usually damaged when the ACL is torn.
  • PCL tear (posterior cruciate ligament): this injury is less common than an ACL tear, as the PCL is much stronger and therefore more resistant to injury. The PCL is usually injured as a result of injury to the tibia; this is particularly common when the knee is bent.
  • MCL tear (medial collateral tear): this injury is much more common than a lateral collateral ligament tear and is usually caused by direct impact or contact; this injury is common in contact sports.
  • LCL tear (lateral collateral tear): this is a relatively rare injury; often this injury occurs as result of damage to other parts of the knee joint.

Causes of ligament tears

Ligaments tears usually occur as a result of an action which stretches the ligaments beyond their limits; usually this involves a sudden or quick movement, a change of direction, twisting movements or trauma.

Symptoms of ligament tears

Collateral tears: common symptoms include swelling, localised pain and a restricted range of movement; a popping noise may also be heard when the injury happens.

Cruciate ligament tears: anterior cruciate ligament tears are extremely painful and may cause an audible pop or crack. The individual may not be able to straighten the leg fully. The area will usually swell considerably. Posterior cruciate ligament tears often cause severe pain, which may radiate to the calf. Swelling will usually be much less evident than an ACL tear. The knee joint will feel weak and may feel like it’s ‘caving in’.

Treatment for ligament tears

Collateral ligament tears: minor tears will usually be treated with a combination of rest, ice, compression and elevation. If the injury is more serious and significant damage has been caused, the knee may be immobilised for a period of time to prevent it from bearing weight. Anti-inflammatory medication and pain relief will help to reduce swelling and ease pain. Physiotherapy will often be used to strengthen the joint and increase the range of movement. Collateral tears usually heal better than cruciate ligament tears.

Cruciate ligament tears: in most cases, an anterior cruciate ligament tear will require surgery to repair the tear. Anti-inflammatory medication and ice will usually be used to reduce swelling prior to surgery. Surgery is used either to repair or rebuild the ligament, depending on the gravity of the injury. Posterior cruciate ligament tears do not usually require surgery and are usually treated with medication to control pain and reduce swelling, ice and rest; the knee may also be immobilised to allow it time to heal. Surgery may be used if other parts of the knee joint have been damaged. Physiotherapy will be used to strengthen the knee and improve movement and flexibility around the joint.

Recovering from a ligament tear

A full recovery will usually be made in athletes who have suffered a collateral or posterior cruciate ligament tear; however, many athletes who suffer an anterior cruciate ligament tear may struggle to regain the same level of performance. Anterior cruciate ligament tears may cause an athlete to be side-lines for up to 9 months, while other types of ligament tear may only take a period of weeks to heal (this will depend on the gravity of the tear and the extent of the damage).

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