Care of your plaster cast

Information for Emergency Department and Urgent Care Centre Patients. Staff working in Chelsea and Westminster Hospital's ED have written this leaflet to remind you of some of the things you will need to know in order to look after yourself. Please read it carefully.

What is a plaster cast?

It is a gauze bandage that has been mixed with certain resins. When this is submerged in water applied to your limb, it becomes solid. 

What is the difference between a 'backslab' and a full cast?

A 'backslap' is a slab of plaster that does not completely encircle the limb and is used for injuries which have resulted n a large amount of swelling.  It is secured with a bandage to accommodate the swelling. This type of plaster is only temporary and will probably be completed at your Fracture Clinic appointment. A full cast encircles the limb and does not need to be secured by a bandage. It only allows for a minimal amount of swelling. 

How long does it take to dry?

A plaster cast will take 24-48 hours to dry completely although it may feel dry by the time you leave the department. It will initially feel very heavy but less so as it dries. Do not try to speed up the process by using a hair dryer or other appliance. During this time you should take extra care to protect the cast. For example do not rest it on a hard surface or write on it. 

What should I look out for?

New or increasing leg pain or shortness of breath: These symptoms are rare but if you experience them you should attend your nearest Emergency Department immediately as there may be signa of a blood clot developing. The medical term for this is a Deep Vein Thrombosis (DVT) or Pulmonary Embolus (PE). 

The Plaster has become too tight

If this happens you may notice: 

  • Swelling of your fingers/toes
  • Numbness or pins and needles in your fingers/toes
  • Pain
  • White or blue discolouration of your fingers/toes and possible coldness
  • Painful rubbing in any area

The first thing you should do is raise the limb. 

Arm cast: Rest cast on a pillow/cushion so that your hand is higher than your elbow. 

Leg cast: Rest cast on pillow/cushion so that your foot is higher than your hip. 

If symptoms do not improve after 1-2 hours please return to us or your nearest Emergency Department. 

Do not attempt to remove the plaster yourself.

Do rest your cast in this way to avoid unnecessary swelling. 

The plaster cast has become too loose, cracked or soft:

Under normal circumstances you should not be able to move the cast up, down or around your limb. It should feel comfortable and the cast should not be cracked at any point nor should it feel soft. 

If you notice any of these things, and your fracture clinic is unable to see you urgently, please return to us or attend your nearest ED. 

Important precautions

Remember if the cast is hurting it need attention. 

  • Never use anything to scratch under the cast as the slightest scratch could develop into a serious infection
  • Never trim or cut down the length of the plaster cast yourself or attempt to tuck in extra padding. 

Can I get it wet?

No. You should never allow your cast to become wet as this will weaken it. You can use a plastic bag to cover up the cast when you have a bath or shower. Try using sticky tape or a rubber band to seal the bag at the top and bottom to make it watertight. Always remove the bag as soon as you can to avoid causing sweating, which could also damage the cast. 

Can I walk on my plaster cast?

No because we have not applied a walking cast. The Fracture Clinic may decide this appropriate at a later stage. 

Can I drive?

We strongly advise that you do not drive with any type of plaster cast. 

How long will I wear the cast?

This is entirely dependent upon the type of injury. 

Should I exercise the affected limb?

Yes, you should exercise in order to avoid stiffness in unaffected joints. We recommend that you try the following gentle movements every couple of hours during the day. 

Arm cast: 

  • Wiggle your fingers
  • Bend and straighten your elbow joint (only if the plaster ends below the elbow)
  • Very gentle rotate your shoulder

Leg cast:

  • Wiggle your toes
  • Bend and straighten your knee (only if the plaster ends below the knee)
  • Gently clench the muscles in the back of your calf and thigh to improve the blood flow. 

Taking care of your plaster cast is vital for your injury to heal properly. 


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