Overview
About Slab Application
A slab (back-slab or half-cast) is a partial cast applied to the back or sides of a limb, held in place with bandages. Unlike a full cast, it allows the limb to swell without the risk of dangerous pressure build-up (compartment syndrome). Slabs are the first-line immobilisation for fresh fractures and severe sprains and are typically converted to a full cast once swelling reduces (usually after 5–7 days).
Key Benefits
Accommodates initial swelling safely — reduces risk of compartment syndrome
Provides adequate immobilisation while allowing monitoring of the injury
Quick to apply — provides immediate relief and stability after injury
Easily removed for wound inspection or swelling assessment if needed
Smoothly transitioned to a full cast once swelling reduces
Frequently Asked Questions
Why is a slab used instead of a full cast initially?
Fresh injuries swell significantly in the first 48–72 hours. A full cast on a swelling limb can become dangerously tight. A slab leaves room for swelling while still immobilising the injury.
When is the slab converted to a full cast?
Usually after 5–7 days once the initial swelling has subsided. A follow-up appointment is given for X-ray review and conversion to a full cast if needed.
Is a slab as effective as a full cast?
For initial management of acute injuries, yes — it provides adequate immobilisation. It is not suitable for long-term use; a full cast or brace is applied once swelling settles.
What should I watch for at home with a slab?
Watch for increasing pain, tightness, numbness, tingling, white or blue fingers/toes, or foul smell from the slab. Go to the emergency department immediately if any of these occur.
Can I shower with a slab?
No — the slab must be kept dry. Use a waterproof bag or cover when bathing. A wet slab loses its strength and can cause skin problems.