Injury of knee ligaments

Fast facts

• The knee has four major ligaments, which allow for a wide range of movement within the knee while still maintaining the knee's stability.

• Knee ligaments are commonly injured when the knee receives a direct blow or when it is suddenly twisted.

• If you suspect your knee may have been injured, it is important that you immediately cease any sporting or physical activity, rest your knee, elevate it and apply ice packs and compression, and seek medical attention.

• Most mild cases of knee ligament injury get better within six weeks. More severe injuries can take up to 3-4 months to fully recover.

What is injury of knee ligaments?

Injury of knee ligaments is the sprain or tear of one or more ligaments in the knee. The knee ligaments can be injured in several different ways. Injuries are commonly sustained by athletes, but can happen to anyone.

The knee ligaments

Ligaments are a type of strong connective tissue that connect bones to other bones, providing stability to joints. The knee has four major ligaments that stabilize the knee joint. Two of those, the anterior and posterior cruciate ligaments, cross one another as they connect the shin bone (tibia) to the thigh bone (femur). They are found deep within the knee joint and allow for a wide range of movement, while still maintaining the joint's stability.

The cruciate ligaments are supported by the two collateral ligaments, the medial and lateral collateral ligaments, found on either side of the knee, which limit the sideways motion of the joint.

Commonly, injury of a knee ligament is associated with damage to other ligaments or structures within the knee, such as menisci (see report on Meniscal tears).

 

Causes

Knee ligaments are commonly injured when the knee receives a direct blow or when it is suddenly twisted.

Different ligaments are damaged in different circumstances:

Medial collateral ligament injury

An injury to the medial collateral ligament usually occurs when the outer side of the knee gets hit, such as during a football tackle.

Lateral collateral ligament injury

An injury to the lateral collateral ligament can occur as a result of a direct blow to the inner side of the knee. This type of injury is common in sports where there are forceful collisions such as in football and hockey.

Anterior cruciate ligament injury

An anterior cruciate ligament injury is a common sporting injury, particularly in skiing, football, basketball and netball. It typically occurs as a result of the athlete suddenly pivoting, decelerating or landing from a jump.

Posterior cruciate ligament injury

This type of injury can occur when the front of a knee is hit while the foot is still planted on the ground. As this ligament is stronger than the anterior cruciate ligament, posterior cruciate ligament injuries are not as common.

Signs and symptoms

Signs and symptoms of knee ligament injury include:

• Swelling, pain and tenderness in the knee or the surrounding area;
• Reduced movement of the knee;
• A popping or snapping sound, which is sometimes heard as a ligament is completely torn;
• A feeling of instability during walking, and;
• Bruising, which may develop some time after sustaining the injury.

Methods for diagnosis

An injury to a knee ligament may be diagnosed by a physical examination. A scan, such as an ultrasound, is frequently used to assess which ligaments are injured. Ultrasound is less useful for assessing injuries to the cruciate ligaments, which are located deep within the knee.

In cases where there is swelling around the knee, magnetic resonance imaging (MRI) or arthroscopy may be needed to evaluate the injury. These techniques provide detailed views of the deeper knee structures.

Types of treatment

First aid

If you suspect your knee may have been injured, it is important that you immediately cease any sporting or physical activity.

To help reduce discomfort and further injury:

• Rest;
• Use icepacks and compression bandages, and;
• Elevate the affected leg.

This can be remembered as R-I-C-E.

Seek medical attention for further treatment.

Medications

Medications for knee ligament injuries include pain-relief medications such as acetaminophen. Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, can also be used to reduce inflammation.

Surgery

In some cases, surgery is necessary to repair a knee ligament injury. This may be a requirement in cases of a complete rupture to ligaments, or if there are additional injuries to other structures.

During surgery, ligaments are reconstructed using a piece of tendon taken from another part of the leg, a process known as autograft. If a section of tendon is obtained from a donor, the procedure is called an allograft.

Physiotherapy

Physiotherapy can improve the movement of the knee and assist with recovery. Physiotherapy may also be useful before and after knee surgery.

Crutches may be recommended to provide support during movement.

It is important not to perform any intense exercises unless your physiotherapist or doctor specifically advises them .

Potential complications

Potential complications of knee ligament injury include:

• Fractures: a fragment of bone can break away from where a tendon or ligament attach;
• Injury to blood vessels: in the event of a knee dislocation, blood vessels can also be damaged, and;
• Nerve injuries: nerves travelling through the leg may also be damaged.

Potential complications from surgery include:

• Joint infection;
• Limited movement: reconstructive surgery on the knee can result in reduced ability to extend the leg. Posterior cruciate ligament reconstruction can limit the bending of the knee, while medial collateral ligament reconstruction affects both straightening and bending of the leg;
• Knee instability due to failure of the graft in the knee;
• Injury to blood vessels and nerves can sometimes occur during surgery. Injury to the nerves can result in complex regional pain syndrome, which can cause severe pain, delaying the progress of physiotherapy, and;
• Although a rare complication, deep vein thrombosis can occur as a result of prolonged immobilization.

Prognosis

With treatment, most mild cases of knee ligament injury resolve within six weeks and the ligaments return to their normal function. More severe injuries can take up to 3-4 months to fully recover.

Prevention

You can lower your risks of injury to knee ligaments by following proper technique during sporting activities. A knee brace may help prevent further damage to a weakened knee. To prevent repeat injury of a knee that had been injured before, physiotherapy programs can speed up recovery of the injured ligaments and strengthen local muscles.