# Backslab/Cast Choice

## Overview

Treating fractures non-surgically requires choice of an immobilising device, depending on the type of injury. In general, acute injuries benefit from a backslab (splint), which allows for swelling while stabilising a joint or fracture, which is replaced later with a more immobilising cast.

## Upper limb

### Phalangeal fractures

1. Thumb fractures: thumb spica splint/cast (digit 1).

2. Proximal/middle phalangeal finger fractures (digits 2-5): dorsal/volar forearm splint with MCPs in full flexion and IPJs in extension. This is the ‘safe’ position of the hand.

3. Distal phalangeal fractures: aluminium U-splint.

Remove splints/casts after 4-6 weeks.

Refer all intra-articular fractures or unstable fractures.

### Metacarpal fractures

1. Thumb (digit 1): thumb spica splint.
2. Fingers (digits 2-5): dorsal/volar forearm splint with buddy taping.
3. Intraarticular or unstable fractures: refer.

Remove splints after 4-6 weeks.

### Carpal fractures

1. Undisplaced carpal fractures: below elbow splint extended to the metacarpal heads for 6 weeks and refer to physio and OT.
2. Displaced, intraarticular or unstable fractures, and all lunate and scaphoid fractures: refer due to high risk of nonunion.

### Radial & ulnar fractures

1. Childhood buckle fractures of the distal radius: dorsal/volar forearm splint for 3 weeks.

2. Isolated, undisplaced fractures of the distal radius: below elbow cast for 6 weeks.

3. Distal radial & ulnar fractures: above elbow full plaster cast, with good 3 point moulding at the forearm, immobilising the wrist and the elbow, with the elbow at 900 flexion.

4. Colles (distal radius) fractures: Below elbow cast, moulding the fracture with 3 point pressure and making sure the metacarpophalangeal joints of the hand are kept mobile.

5. Undisplaced radial head or neck fractures: arm sling for 3 weeks.

6. Midshaft/proximal ulnar or olecranon fractures: above elbow splint/cast for 4-6 weeks.

7. Unstable, displaced or intra-articular fractures: refer.

### Humeral fractures

1. Distal humerus fractures: above elbow splint/cast for 4-6 weeks.

2. Midshaft fractures: U slab/splint for 6 weeks.

3. Proximal humerus fractures: collar and cuff for 6 weeks.

4. Displaced or unstable fractures: refer.

## Lower limb

### Tarsal, metatarsal & phalangeal fractures

1. Distal metatarsal fractures: below knee cast/splint for 4-6 weeks.
2. Phalangeal fractures: buddy strapping to the adjacent uninjured toe.
3. Undisplaced tarsal & metatarsal shaft fractures: below knee cast/splint for 4-6 weeks.
4. Intra-articular or unstable fractures: refer. Obtain a standing X-ray to assess for instability and displacement of tarsal or tarso-metatarsal fractures and dislocations to exclude a Lisfranc injury.

### Tibial & fibular fractures

1. Ankle fractures: below knee cast for 6-8 weeks.
2. Fibular fractures: below knee splint for 6-8 weeks.
3. Tibial or tibia & fibula fractures, use an above knee cast/splint for 6-8 weeks and then convert to a below knee cast, patella bearing for another 6-8 weeks.
4. Intra-articular, unstable or displaced fractures: refer.

## References

1. Boyd AS, Benjamin HJ, Asplund C. Splints and Casts: Indications and Methods. Am Fam Physician. 2009 Sep 1;80(5):491-499. Available from: https://www.aafp.org/afp/2009/0901/p491.html
2. Held M. Orthopaedics for Primary Health Care. Available from: https://www.ortho.capetown/primary-care-orthopaedics