Knee injuries – collateral ligaments

A collateral ligament can be partially torn apart and yet the knee may still remain fairly stable. How do collateral ligament injuries occur?

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What types of knee injuries are there?

In the knee, there are several important structures which make up the joint and help to support and protect it: the collateral ligaments, the meniscus, cruciate ligaments and articular (joint) cartilages.

If there is an injury to the knee, it is possible that more than one of these structures may be injured at the same time.

What are collateral ligaments?

Collateral ligaments are found on both sides of the knee joint - on the inside and outside of your leg.

Ligaments are tough fibrous bands which attach bones to bones. Collateral ligaments run from the bone above the knee to the bone beneath the knee, on both sides. They help to keep the knee stable and stop it slipping in a side to side direction.

A collateral ligament can be partially torn apart and yet the knee may still remain fairly stable. This is because a collateral ligament is not a single, thin ligament, but consists of many minor ligaments in different directions and layers, which mesh together into one single strong ligament.

How do collateral ligament injuries occur?

A ligament injury may occur when the knee is strained from the inside, but more often than not, it will be caused by a strain from the outside.

For example, while playing football, the outside of the knee may be hit or kicked with great force by an opponent. As the knee is pressed together on the outside and forced apart on the inside, the ligaments on the inside of the knee will be injured.

A ligament injury may also occur in connection with a twist within the knee joint itself without any external pressure being applied.

When a collateral ligament is damaged, the extent of the damage may vary from just a small crack in one of the small ligaments to a total rupture of the entire collateral ligament.

A ligament injury may be accompanied by major or minor swelling of the knee joint.

What should be done if a knee injury occurs?

Injuries of this kind should receive first aid treatment following the RICE principle – which stands for Rest, Ice, Compression and Elevation.

Cooling the injury as fast as possible will reduce the swelling and pain.

Rest

The injured knee must be rested for the first 24 to 48 hours to prevent any further injury.

Ice

The damaged area must be cooled by using an ice-pack or a packet of frozen peas. The ice must never come directly into contact with the skin or the patient could get frostbite.

A cloth should be placed between the ice and the skin. Ice can be laid on the affected area for up to 20 minutes every hour, but for no longer than three hours in all.

Ice treatment has been known to be effective for up to 24 hours after the injury occurred.

Compression

An elasticated support bandage is designed for this purpose. The compression must be firm but not so tight that it interferes with the blood circulation.

Elevation

The leg must be elevated above heart level if possible. It is most comfortable to lie down and elevate the limb with a few pillows. If you are sitting down, the leg can be raised on a chair or a table. This elevation should be maintained as much as possible for a few days.

How does the doctor diagnose ligament injuries?

The doctor will check if your knee is swollen. The extent and speed of joint swelling may indicate the seriousness of the injury. The doctor will also check for soreness along the collateral ligaments or where they are connected to the bone.

The doctor will then carefully check for sideways looseness by moving the knee gently from side to side, both when the knee is bent and straight. When the knee is completely straight, there should be no looseness whatsoever.

If the injury is acute, the knee may be too sore to examine thoroughly. In this case, the doctor might either apply a local anaesthetic to the knee or put a splint on the knee and re-examine it after 8 to 10 days.

As ligaments do not show up on X-rays, an X-ray will only be required to rule out the possibility of any injury to the bone.

How are ligament injuries treated?

In the case of a mild injury, the only treatment required may be wearing a compression bandage to support the knee.

In the case of more serious injuries, the patient may be required to wear a splint on the knee for five to six weeks. The splint will allow the knee to be bent or extended, but braces in the splint will prevent the knee from moving from side to side.

These injuries rarely require surgery.

Physiotherapy to exercise the muscles and work on balance may be necessary.

It is important not to resume strenuous exercise until the knee is no longer sore and it feels completely stable.

Other people also read:

Knee injuries – the articular cartilage: Find out what treatment is available?

Knee injuries – cruciate ligament: How do injuries to the cruciate ligaments occur?

Knee injuries – meniscus: What are the symptoms of a meniscus injury?

Arthroscopy: What happens during an arthroscopy?

Anaesthesia: What does the anaesthetist do?

Based on a text by Hans Gad Johansen, specialist, Dr Ejnar Kuur, consultant

Last updated

Consultant orthopaedic surgeon
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