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What is the right time to get a cast changed?

Broken bones need to be held still to allow them to heal. When you break a bone, you may be put into a plaster cast. The cast may be made out of plaster of paris or a synthetic material. The liner of the cast may be a soft cotton wool or a waterproof material. The cast should be comfortable to wear, holding the affected bone still, without feeling tight or having any areas of pressure.

If you have a non-waterproof cast, with a cotton wool style liner, you will need to get the cast changed if it gets wet. The liner will retain the moisture and remain damp. Having a damp liner against your skin can cause skin maceration and breakdown. If a plaster of paris cast becomes wet, then it can soften and fall apart, no longer providing rigid support to your broken bone.

If you notice any of the following, then you should contact you therapist immediately, as the cast may need to be changed:

Rash: A rash may develop due to an allergy to the casting material, an area of pressure from the cast, or even a wound or infection under the cast. The cast will need to be removed, so the skin can be checked and treated as necessary.

Burning sensation: A burning sensation may be a result of irritation of a nerve. This can occur when the cast is pressing on nerve that is close to the surface of the skin. It may also occur if the swelling from the broken bone, or the broken bone itself, is irritating a nerve. The cast needs to be removed to check and relieve the source of the burning symptoms.

Rubbing or pressure from the cast: If the cast feels like it is tight, putting pressure on a certain area, or rubbing at the edges then it needs to be changed. Rubbing or pressure areas can lead to skin breakdown and wounds.

Increased pain or swelling: Symptoms related to your broken bone should start to resolve when you are put into a cast. If you notice an increase in pain or swelling, this can be a sign that something is not right and your cast may need to be changed.

Pins and needles or numbness: These can occur if your swelling has increased and your cast has become too tight. Your cast should be removed to relieve any pressure and resolve these symptoms.

Cast is too loose: If your swelling reduces, you may notice you can move around inside the cast, or in some cases even slip the cast off! In this case, your cast needs replacing with a new firmer cast.

If you have any concerns during your time in your cast, then you should contact your therapist immediately.

We work closely with people who experience broken bones in their hands and wrists. If you need further advice, please feel free to contact us on 02 6925 0157 or


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