Plaster of Paris: what to know

Plaster of Paris is applied as wet bandage layers that are shaped around the injured area. As it sets, it becomes a firm support. Its moulding quality helps the clinician create a close fit around a limb, although swelling may affect comfort and the cast may need review. The material is used in fracture casting and in some staged correction programmes, including clubfoot casting.

The cast controls movement; it does not repair the bone by itself. The treatment plan also depends on the injury, alignment, examination, and follow-up. A cast can be changed or replaced if the fit, skin, or healing needs require it.

Protect the cast from water during bathing and allow it to dry naturally if the outside becomes damp. Do not cut it, rest heavy objects on it, or push anything beneath it. Elevate the limb when swollen and move exposed fingers or toes as instructed. Avoid impact and unapproved weight-bearing. Keep the scheduled review so the fit and the healing plan can be checked.

Contact the treating service urgently for severe or rising pain, numbness, tingling, pale or blue digits, coldness, or reduced movement. A wet, cracked, loose, tight, foul-smelling, or draining cast also needs prompt advice. Fever or skin pain at the cast edge should not be ignored, particularly if the cast is difficult to inspect.

Ask how long the cast should remain, how to bathe safely, whether any walking or loading is allowed, how to manage itching, and which changes mean you should return early. For a child’s casting programme, ask how home positioning and follow-up fit together.