# Plaster Cast Application

## Overview

This module describes how to apply a definitive circumferential cast to immobilise a fracture.

## Indications

## Contraindications

## Patient information and consent

Always verify your patient’s identity and obtain informed consent before proceeding.

### How do I explain this procedure?

“This broken bone will need to stay completely still for a few weeks to heal. I’m going to make a plaster cast for it that will keep it from moving while it is healing.”

### What can my patient expect?

“I’m going to wrap a few layers of bandages around your limb, then put on some layers of plaster that will harden within a few minutes. The cast may feel warm as it hardens. It will take a day to be fully hardened.”

### What is my patient’s role?

“Let me know if you feel any areas where the cast is pressing against you too hard, or where it feels uncomfortable or painful. While the cast is still hardening today, try not to move your limb around too much. Come back to the clinic tomorrow for a cast check, and after x weeks, come back again so we can remove the cast. Don’t let your cast get wet or dirty. You can wrap it in a plastic bag during showering. Don’t insert objects into the cast, such as a ruler to scratch itchiness.”

## Preparation

X-rays should be taken before casting, and the degree of displacement should be assessed.

Undisplaced or minimally displaced fractures usually do not require reduction. Displaced fractures need to be

reduced

reduced

Reduction is usually accomplished by longitudinal traction, followed by exaggerating the displacement, followed by three-point pressure to reduce the displacement. Ensure adequate analgesia or conscious sedation while performing the reduction.

first.

Prepare a trolley with equipment. An assistant may be helpful in holding the reduced fracture in place and supporting the limb.

### Documentation

### Equipment

## Site & Positioning

The type of fracture dictates the position in which a limb is immobilised. For choice of cast, see Cast/Backslab Choice.

Thumb spica cast: forearm in neutral position, wrist in 25° extension, thumb in position of function (holding a can). Apply the cast ​​from the proximal one third of the forearm to just distal to the interphalangeal joint of the thumb.

Below elbow cast: forearm in neutral position, wrist neutral or slightly flexed. The cast is applied from the proximal forearm to the proximal palmar crease.

Above elbow cast: forearm in neutral position, elbow bent 90°, wrist neutral or slightly flexed. The cast is applied from the proximal upper arm, just beneath the axilla, to the proximal palmar crease.

Below knee cast: ankle in neutral. Avoid plantar flexion. The cast is applied from just proximal to the toes to just below the knee. Make sure that it is low enough for the knee to flex to 90°.

Above knee cast: ankle in neutral, knee slightly flexed. Avoid plantar flexion. The cast is applied from just below the greater trochanter to just proximal to the toes.

## Procedure

Follow medical asepsis with non-sterile gloves.

## Troubleshooting

My patient came back complaining of pain inside the cast.

Severe pain, especially pain on passive stretching of the limb, could be a sign of developing

compartment syndrome

compartment syndrome

Signs and symptoms of compartment syndrome include severe pain, pain with passive stretching, poikilothermia, paraesthesia, pulselessness, pallor, and paralysis.

. If a patient complains of pain, split the cast on 2 sides (bivalve), including the padding and stockinette. If splitting the cast resolves the problem, a firm bandage is wrapped around the split cast to keep the fracture immobilised. The cast can be completed in 5-7 days once swelling has resolved. If the symptoms do not resolve, remove the cast completely and evaluate for compartment syndrome.

My patient is complaining of a burning sensation inside the cast.

Pressure ulcers can develop within hours in poorly fitted casts. Remove the cast and assess for cast sores. Re-immobilise with a cast with a window cut out of it over the affected area, or with a backslab.

## Risks

## References