As you will no longer be able to move your affected limb as freely as you were able to before the injury, there is risk that a blood clot could form. This is usually in the deeper veins of the legs, which is commonly known as a Deep Vein Thrombosis (DVT). This can be very painful, resulting in swollen and sometimes discoloured calves.
Am I at risk?
Blood normally flows quickly through veins, and does not normally clot. Blood flowing in the leg veins is helped along by movements, because muscle action squeezes the veins. Whilst your leg is immobilised you will find it difficult to have a full range of movement you are used to and may potentially be at risk of a DVT.
Your doctor or nurse will perform a risk assessment whilst you are in the emergency department and a decision will be made whether to prescribe you medication or not to prevent a blood clot.
The impact of medication
DVT and more rarely pulmonary embolism (PE) occur in between one in 50 and one in 18 people who have their lower limb immobilised in a plaster cast, splint or walking boot. If you are unable to bear weight, are over 60 years old, have other risk factors such as previous DVT, PE or active cancer, then this puts you at much higher risk of developing a DVT or PE. One or two people out of every 5 with multiple risk factors will develop a DVT or PE.
Medication will reduce the risk of developing a DVT or PE by around half but does not completely remove the risk. If you develop any signs of DVT and PE as list below despite being on treatment you should see urgent medical attention or call 111.
What happens if I don’t need medication?
If your doctor or nurse has decided that you don’t need any anticoagulation medication as you are at low risk of developing a blood clot, then you will be discharged home without any anticoagulation medications. All patients will receive a follow up for the fracture clinic as an outpatient normally within seven days.
General advice to anyone with their lower limb immobilised would be to stay as active as possible within the limitations mentioned to you by the healthcare professional in the ED. Drink plenty of fluids (not alcohol) to stay hydrated and be alert for any signs of DVT.
Recognising the signs of DVT
When you have DVT the blood flow in the vein is partially or completely blocked depending on the width of the clot. A calf vein is the common site for a DVT. A thigh vein is less commonly affected. Rarely, other deep veins in the body form clots.
The affected area of the blood clot may become swollen or painful, and possibly turn red as the flow of the blood is blocked. You may also develop oedema, which is the build-up of fluid in the skin tissues surrounding the clot. If the clot is somewhere other than in your leg, there may be no physical signs of DVT.
Sometimes bits of the clot can break up and lodge in the lungs causing a pulmonary embolism causing chest pain and difficulties with breathing.
Sometimes a DVT occurs for no apparent reason, and it becomes more common with age. Each year, one in every 1,000 people in the UK is affected by DVT.
If you develop any of these signs or symptoms listed above, seek medical attention immediately.
Reducing the risk of DVT if you are treated in a splint or a cast and not weight bearing through it.
Below explains important information about the care of your plaster cast and about the risk of blood clots or VTE.
The risk of blood clots and plaster casts
- Most people in plaster casts do not go on to develop blood clots. However, plaster casts can increase the risk of blood clots forming in the veins. These clots can block the flow of blood and cause pain and swelling (DVT). Occasionally, the clot can travel through your circulation and reach the lungs. This is called a pulmonary embolism and can cause coughing (sometimes with blood), chest pain and breathlessness.
- It can be dangerous and needs urgent treatment.
Reducing the risk of developing a DVT
Some people have a higher risk of developing clots. Your doctor may recommend preventive treatment in the form of injections or tablets. If any of the following apply to you, please tell a member of the healthcare team:
- You have ever had a DVT or PE
- You are on cancer treatment or have a current cancer diagnosis
- You are pregnant (or if you gave birth fewer than 6 weeks ago)
- You have injured your Achilles’ tendon.
If your injury needs treating in a way that you cannot walk fully on that leg, a clinician will risk assess you and discuss a treatment plan. This will also happen if you have an injury which is treated in a walking boot and you can fully walk on the injured leg then normally medications are not needed.
It's difficult to predict who will get a blood clot, and there are steps that can be taken to try and reduce this risk:
- Drink plenty of fluids.
- Move around as much as is comfortable.
- Stop smoking - this will also help your bone to heal.
- Perform the exercises described below.
- Exercises for reducing the risk of DVT in lower limb casts.
- While you must wear a cast, any activity which promotes contraction of muscles and increased blood flow is helpful.
Exercises
Try and do the following at least three times a day.
For any cast on the legs
- Wiggle your toes while lying in bed or whilst sat up with your leg elevated.
- Try and do this for at least 10 seconds and as often as you can. This promotes blood flow and can help reduce the risk of blood clotting.
- Inside the plaster cast, if it is safe to do so, try and move your ankle up and down. It will not move very much as the cast will stop it. Repeat 10 times. If the cast feels loose or is rubbing, contact the hospital using the numbers on the front of the leaflet.
For below knee casts only
- Regularly bend your knee. Sit down, bend your knee and then straighten your knee. Repeat ten times.
- Lie on your tummy on the bed and bend your knee, bringing Your heel towards your bottom. Slowly lower your foot back down to the bed, keeping he movement slow and controlled.
- Lie on your bed or sit up with your leg raised. keeping your leg straight, brace the knee and keeping the leg straight, lift the whole leg up approximately 5cm, Hold for five seconds then slowly lower it down again.