Knee ligament injuries

What are knee ligaments?

Ligaments are strong cords of tissue that hold joints together and connect them to the adjacent bones. There are four in the knee

  • medial collateral ligament (MCL)
  • lateral collateral ligament (LCL)
  • anterior cruciate ligament (ACL)
  • posterior cruciate ligament (PCL)

Any one of these ligaments, or a combination of them, can become stretched, or partially or completely torn

What causes collateral ligament injuries and who is at risk?
The usual causes of torn knee ligaments are over-extension of the leg during exercise or injury during contact sports.

The MCL (medial collateral ligament), located on the inside of the knee joint, helps keep your knee joint stable. It can be injured by stressing, twisting or striking the knee. Most minor MCL injuries heal by themselves in a few weeks or months if they are rested. Serious ones, however, often require surgery.

Like the MCL, the LCL (lareral collateral ligament) helps keep your knee joint stable but is located on the outer side of the joint. Most minor LCL injuries heal by themselves in a few weeks or months if they are rested but more serious ones may require surgery.

Usually the injury to the LCL damages another ligament at the same time. In most cases, LCL injury is less serious than injury to other knee tissues, such as the cruciate ligaments. However, in more serious cases the ligament can be partially or completely torn.

Blows to the knee are a common cause of LCL injury but any twisting injury may result in damage. LCL damage is a common sports injury.

What are the common symptoms and complications of collateral ligament injuries?
Damage to the MCL will cause tenderness on the inside edge of the knee and in some cases there will also be swelling. Partial or complete tearing will cause more severe pain and swelling.

Damage to the LCL causes pain and tenderness on the outside edge of the knee and there may also be swelling.

How do doctors recognise collateral ligament injuries?
See a doctor as soon as possible if you have pain or swelling after a knee injury during exercise, sport or an accident.

The doctor will test for an MCL injury by bending your lower leg outward. If the doctor can bend the lower leg outward more than normal you may have partially or completely torn the ligament.

The doctor will test for an LCL injury by bending your lower leg inward. If the lower leg does not bend inward abnormally, any LCL injury will be minor. If the doctor can bend the lower leg inward more than normal, you may have partially or completely torn the ligament.

Other tests for both MCL and LCL injuries include:

  • an X-ray,
  • an MRI (magnetic resonance imaging) examination.

What causes cruciate ligament injuries and who is at risk?
The anterior cruciate ligament (ACL) runs from the bottom rear of the thigh bone (femur) to the top front of the shin bone (tibia). The posterior cruciate ligament (PCL) runs from the bottom front of the femur to the top rear of the tibia. They cross each other, forming an ‘X’.

These ligaments can be injured by:

  • coming to a sudden stop, especially when running,
  • changing direction while running, turning or landing from a jump,
  • running downhill,
  • twisting the knee,
  • stretching the knee joint too far to right or left,
  • blows to the knee.

The PCL is stronger than the ACL and therefore less prone to injury. ACL damage, on the other hand, is one of the most frequent sports knee injuries.

What are the common symptoms and complications of cruciate ligament injuries?
When you damage your ACL, it is common to hear a distinct popping sound. You may also feel something snap inside your knee. Other symptoms include:

  • swelling,
  • an unstable knee, making it difficult to walk,
  • the knee locking during movement,
  • pain and tenderness.

PCL injury usually does not cause the ‘pop’ sound you hear when you injure the ACL . Other symptoms of a PCL injury are similar to those in ACL injuries.

How do doctors recognise cruciate ligament injuries?
The doctor will test for an ACL injury by pulling the lower leg forward while holding the thigh still. If your knee appears loose, it is usually a sign of an ACL injury.

For a suspected PCL injury, you may be asked to lie on your back then raise your legs so that your thighs point straight up, with your knees bent at right angles. If your lower leg sags toward the floor, your PCL is probably torn.

The doctor may also press gently over your kneecap to feel for fluid in the joint, especially if the injured knee is not severely swollen.

Other tests include:

  • an X-ray,
  • an MRI examination.

What is the treatment for knee ligament injuries?
Treatment usually includes physiotherapy and special exercises. Sometimes ultrasound treatment is prescribed. If the MCL is the only ligament injured, you usually do not need surgery. However, if you have also damaged other ligaments, you may need surgery. The younger and more active you are, the greater the chance that you may need surgery following a serious ligament injury.

You may be able to return home the same day after knee surgery but you may need to use crutches for a week or so. Athletes will probably be fit to return to their athletic pursuits nine months after the injury.

Many injuries to the knee ligaments cannot be avoided because rough contact is such an integral part of many sports, such as football and rugby. Athletes are also at risk because strenuous movements such as jumping and turning are such important parts of the sport.

  • To reduce the risk of knee ligament injuries:
  • exercise regularly to stay in shape,
  • stretch and warm up before starting the activity,
  • wear kneepads or other suitable protection,
  • stick to the proper technique for the activity,
  • wear properly cushioned sports footwear,
  • train on appropriate surfaces.

Self-care action plan

The first aid treatment is the same whichever ligament is injured. Follow the RICE procedure:

  • Rest the injury by avoiding movement of the affected joint.
  • Ice packs or cold compresses should be applied to the knee to reduce swelling.
  • Compress the joint by bandaging it, firmly but not too tightly, with an elasticated support bandage
  • Elevate the joint by keeping it supported above your heart, especially at night while sleeping.
  • On the first day of the injury, put ice on the affected area for 15 minutes. Then remove the ice for 15
  • minutes. Repeat this cycle throughout the day.
  • Lie down and support the knee in an elevated position. Avoid flexing the knee joint or putting any strain
  • on it until the pain and swelling subside.
  • A painkiller or anti-inflammatory medication such as aspirin or ibuprofen may help.

What is the outlook for knee ligament injuries?
Most knee ligaments either heal completely or their mobility is fully restored after surgery. However, the ligament may not heal completely, which can lead to long-term weakness in the joint. Unfortunately, once you have had an injury you will have a higher chance of hurting the ligament again, even during less strenuous activity.

Good luck and have a nice and safe training!