1. How to apply a short arm cast
Alison Herron

2. Patient X
Patient X has presented at A&E with a painful left wrist sustained after a fall off a quad- bike that morning. The patient’s left distal radius is swollen and tender to the touch. The patient experiences pain on extension of the thumb. Patient X has no diagnosed medical conditions and no known drug allergies.
PRESENTATION NOTES
This example clinical case illustrates the initial steps involved in examining a patient who has presented to A+E;
Firstly, take a history of the presenting complaint
Examination: look/feel/move the area of complaint.
If a fracture was suspected, the next step would be to send the patient for an X-ray

3. Patient X
In this case, the X-ray indicates the presence of a fracture.
Specifically, this is a Salter-Harris type II fracture of the distal radius
I.e.: a fracture involving the epiphyseal plate. A type II fracture is through the growth plate and the metaphysis but spares the epiphysis.
Therefore, this patient needs a short arm cast and this presentation will explain the various steps involved in applying a cast.

4. Step 1: Preparation Appropriate width Stockinette: Formflex padding
2cm for paediatric patient
3-5cm for adult patient
Formflex padding
Appropriate width of plaster (Gipsona):
5cm for paediatric patient
7.5cm for adult patient
Fill basin with room temperature water
Comfortably position the patient
The first stage is preparation.
Gather the necessary equipment; stockinette, padding and plaster, then comfortably position the patient.

5. Step 2: Stockinette
Measure length of stockinette against length of patient’s arm
Cut thumb hole in stockinette
Place stockinette on patient’s arm
Then, prepare the stockinette. Begin by measuring length of stockinette against patient’s arm- it should extend 3-4cm beyond area to be cast at each end.
After cutting a thumb hole, place stockinette on patient’s arm

6. Step 3: Padding
Begin wrapping the padding proximal to the fracture site
When wrapping, overlap the layers by 50%
The next step is wrapping the formflex padding around the area to be cast.
When wrapping, ensure you begin proximal to the fracture site and that the layers overlap by 50%

7. Step 4: Plaster
Holding the free edge of the roll, submerge the entire roll of plaster in the bucket of water
Remove the roll and squeeze gently to remove any excess water
Roll out the plaster, starting proximal to the fracture site
When plastering around the thumb, twist the roll as shown
The first step of applying plaster is to submerge the roll in the basin of water.
Repeat the same procedure for wrapping the plaster as was used for wrapping the formflex padding; start proximal to fracture site and overlap by 50%.
When plastering around the thumb it is important to twist the roll in order to prevent excess build up of plaster around the thumb which would restrict movement.

8. Step 4: Plaster continued..
When starting a new roll of plaster, ensure the ends overlap in order to form a strong cast
After one layer of the cast has been plastered, tuck the excess layer of stockinette over the layer of plaster
-After one layer of plaster has been applied, fold the excess layer of stockinette over the layer of plaster. This will ensure that once the cast has been finished, there are no rough edges.

9. Step 4: Plastering continued..
Repeat the plastering procedure until the entire cast has been formed from two layers of plaster
Using excess water, smooth down the surface of the plastercast
Repeat the wrapping procedure until the entire cast has two layers of plaster; in a short arm cast this usually requires four Gipsona rolls (i.e. two rolls per layer)
Then, use excess water to smooth the surface of the plastercast in order to prevent the cast catching on patients clothes or causing irritation if it rubs against patients skin.

10. Step 5: Finishing touches
Clean the patients skin of any residual plaster
Cut away any extra padding around the thumb to improve mobility
Washing a patient’s hand of any residual plaster is to prevent dry plaster caking on the patients hands – which is hard and uncomfortable to remove
The final step in applying a plastercast is to cut off any extra padding around the thumb in order to improve mobility.

11. Patient X
-After a cast has been applied to a fracture, particularly when traction has been used, it is often re-x-rayed in order to check the fracture is re-positioned correctly.

12. The Short Arm Cast has now been correctly applied
Typically, a patient will need to keep the cast on for two weeks before it will be replaced by a fibreglass cast
Patients should be advised to keep the cast dry, and to initially keep the limb elevated
When a short arm cast has been correctly applied, it will usually need to be in position for two weeks, in order to allow any associated swelling to go down.
Patient’s should be advised regarding the care of their cast particularly regarding keeping the cast dry by covering it with a plastic bag in the shower or bath etc. Getting the cast wet will cause it to soften and potentially break-apart
Patient’s should also be advised to initially keep the limb elevated as it will help any swelling go down and will allow the cast to dry properly

13. Step 6: Removing the cast
A short arm cast is usually removed after two weeks
Use an oscillating saw to cut a straight line along the length of the cast
The final stage of applying any cast is removal.
The oscillating saw is used to cut a straight line, through the plaster layer, along the length of the cast.
This stage is particularly distressing for paediatric patients, mainly due to the noise the saw makes. It is important to demonstrate that an oscillating saw just rapidly vibrates and that it cannot cut or harm the patient.

14. Step 6: Removing the cast continued..
Use large plaster spreaders to open out the incision made in the cast
Once opened, cut the padding and stockinette with blunt ended scissors
Plaster spreaders are then used to open up the incision made using the oscillating saw.
Once open, blunt ended scissors are used to cut through the padding and stockinette layers.
The cast can then be removed

15. References www.handcare2012.com/forms/Hand_Care_cast_lecture.pdf
With thanks to Andy the ‘master plasterer’ 