Lateral Knee Ligament Sprain

Lateral Knee Ligament Sprain

The lateral collateral ligament is a relatively large ligament attached to the outer side of the knee. It joins the femur (thigh bone) to the fibula and hence is also known as the fibular collateral ligament. It is a strong, narrow, fibrous cord that extends from the outer side of the lower end of the femur to the upper end of the fibula (the smaller leg bone present on the outside). It stabilises the outer part of the knee joint and prevents excessive sideways movement.


A sprain is an injury to the ligament. The lateral ligament may acquire a sprain when an undue sudden force is applied to the inner aspect of the knee, such as while playing contact sports, soccer, rugby, or in an accident.

An excessive external rotation of the knee would also injure the lateral collateral ligament as well as its medial counterpart.

Other ligaments such as the anterior and posterior cruciate ligament may also be damaged concurrently.

Intensity of sprain:

Grade I: the ligament is excessively stretched, however only a few fibres are torn, no effect on stability

Grade II:the ligament is stretched to a point that it becomes loose, most of the fibres are torn, and the stability of the joint is affected

Grade III: complete tearing or rupture of the ligament resulting in an unstable joint.


Pain is the most common indication of injury. The intensity varies according to the extent of damage.

Grade I sprains:

In a grade I sprain usually there is no swelling, only slight tenderness over the outer aspect of knee.

Applying outward pressure to a bent knee, such as bending the shin inwards, elicits pain.

The joint is stable.

Grade II sprains:

There is swelling and increased tenderness in the area.

When an outward force is applied to the bent knee, significant pain is felt.

The joint is slightly unstable.

Grade III sprains:

A popping/snapping sound may be heard at the time of incident.

The joint is significantly unstable.

Swelling and pain which may be quite intense, though it may vary.


History of the trauma, i.e., how the injury occurred, as well as the signs and symptoms, clearly indicate the diagnosis.

X-rays help to rule out any associated bone fractures.

MRI gives a clear picture of the extent of injury to the ligament.


In the initial stage follow the RICE protocol. Discontinue any activity that leads to pain. Apply ice packs and compression to the knee and elevate the injured leg. All this helps to reduce inflammation. NSAIDs help with pain and swelling.

For mild to moderate (grade I & II) tears, conservative therapy usually works well:

  • Continue with the rest
  • Support the knee using a hinged knee brace
  • Ultrasound or manual massage to accelerate healing
  • Use a heat retainer

Surgery is indicated when:

  • Symptoms do not improve with conservative therapy
  • The lateral ligament is completely torn
  • Other ligaments or joint structure are also damaged.

The torn ligament ends are stitched together or in the case of an avulsion fracture, the ligament is fixed to the bone, along with the fractured piece, with the help of pins.

Sometimes, grafts from nearby tendons may be used to repair a badly torn ligament.


Rehabilitation should start as soon as the symptoms subside and movement is possible without pain.

The aim of rehabilitation is to:

Improve the range of motion

Strengthen the leg muscles to reduce load on the joint structure and thus the ligaments

Restore normal function


In the first phase of rehabilitation, focus on gradual return to activity. Start with mild flexion and extension of the knee. Keep the motion passive in the early stages to further reduce the stress. Use a towel or band to move the ankle.

Later on, bend the knee in the standing position against gravity or, placing the foot on a bench, push forward with your body.


Stretch the leg muscles gradually, keeping in mind not to cause pain. Be slow and steady. Hold each stretch for about 20 seconds or more if it doesn’t hurt. An undue stress at this early stage of recovery may delay the healing process.


Once you regain complete range of motion, start with muscle strengthening exercises. Start with easy exercises and proceed to a more difficult level. Improving muscle strength helps to take the load off the knee joint.

Sports massage:

Sports massage is a great adjunct to the healing process and should be done at least 2-3 times weekly. Massage improves circulation to the area, providing the nutrients and removing the wastes more efficiently. Cross friction massage is recommended for ligament healing.

Once you are completely pain free and feel strong enough, you can begin running or jogging. Lateral collateral ligament injuries are slower to heal than medial collateral ligament injuries. Serious sprains may take up to two to three months until normal activity can be resumed.