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Leaflet: Lower Limb Immobilisation

Following your visit and assessment at the Minor Injury Unit (MIU), you have been advised that you need a plaster cast, splint or special support applied to your lower leg.

As a result you won’t be able to move your leg, and studies have shown that this can increase your risk of developing a blood clot. This is called a Deep Vein Thrombosis (DVT).

What is DVT?

A DVT is a blood clot in a vein. Blood clots in veins most often happen in the legs but they can occur elsewhere in the body.

The most common cause of a blood clot developing is not moving. A problem can occur in some cases where part of the clot breaks off and travels to the lung causing a Pulmonary Embolus (PE). A large PE can be fatal.

Why do blood clots form in leg veins?

Blood normally flows quickly through veins and does not usually clot. Blood flow in leg veins is helped by leg movements, because muscle action squeezes the veins. Sometimes a DVT can occur following injury and not moving because of the injury. You may not have moved your lower leg for a long time. This causes the blood flow in the veins to be slow. Slow flowing blood is more likely to clot than normal flowing blood.

Symptoms to look out for

A DVT most commonly develops in a deep vein below the knee in the calf but it can occur in the thigh. Typical symptoms include:

  • Pain and tenderness of the calf or thigh
  • Swelling of the calf or thigh
  • Colour and temperature changes of The calf or thigh as blood that would normally go through the blocked vein is diverted to outer veins. The calf may then become warm and red.

Symptoms of Pulmonary Embolus (PE)

  • Shortness of breath
  • Chest pain

You must go to your nearest Accident and Emergency Department if you develop any of the above symptoms.

If you develop severe chest pain or shortness of breath then dial 999 for an ambulance.

Call 111 if you urgently need medical help or advice but it’s not a life-threatening situation.

For less urgent health needs, contact your GP or local pharmacist in the usual way.

Visit the Minor Injuries Unit webpage for more information about this service.

This leaflet can be provided in other formats and languages, please contact us for more information.

Date of creation: July 2021
Date of review: July 2023
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