Immobilisation - Short leg backslab
Indications
Fractures of:
Distal tibia and/or fibula
Tarsal
Metatarsal (for non-weightbearing management)
Contraindications (absolute in bold)
None
Alternatives
Open reduction with internal fixation
Informed consent
Verbal consent
Less complex non-emergency procedure with low risk of complications
Potential complications
Failure (reduction or immobilisation)
Thermal burns (from heat released during setting of plaster)
Neurovascular compromise
Pruritis
Dermatitis
Abrasions and pressures sores (with risk of infection)
Joint stiffness
Venous thromboembolism
Procedural hygiene
Standard precautions
PPE: non-sterile gloves, apron
Area
Plaster room or bed space
Staff
Procedural clinician and assistant
Equipment
Stockinette (optional)
7.5 and 10cm cotton padding (for foot and leg)
15cm plaster for backslab (slightly wider than leg diameter)
10cm plaster for stirrup (approximately leg diameter)
Trauma scissors
Bowl of cold water
Crepe bandages
Tape
Positioning
Supine or prone with assistant supporting weight of leg
Assistant maintains position of limb while proceduralist applies plaster
If supine, a towel placed under the knee can assist maintaining position
Ankle: flexion to 90 degrees (neutral position)
Subtalar joint and hindfoot: neutral inversion/eversion
Cast
Estimate plaster length by laying dry splint next to the area to be splinted (use uninjured leg)
Layers: 12-layer backslab along posterior leg, eight layers for stirrup from above midcalf to above midcalf
Distal margin: distal to metatarsal heads on plantar surface (continue beyond toes for phalangeal fractures)
Proximal margin: 2cm below head of fibula
Medication
Consider paracetamol 1g, ibuprofen 400mg and oxycodone 5mg (pain relief one hour pre-procedure)
Consider fentanyl 25-50mcg IV (pain relief pre-procedure adjusted to co-morbid status)
Consider fentanyl 100mcg (1.5mcg/kg pain relief pre-procedure adjusted to co-morbid status)
Sequence
Ensure adequate analgesia prior to procedure
Inspect the extremity prior before splinting, document lesions repairing or dressing as normal
Apply stockinette to leg beyond margins of plaster (allowing folded to a smooth edge)
Apply 2-3 layers of cotton padding beyond plaster margins, proximally and then distally
Ensure heel and malleoli are well padded with padding overlapping itself by 25-50% with minimal creases
Submerge the pre-prepared dry backslab in water until bubbling stops, then remove
Squeeze out excess water, smooth on a flat surface
Apply on posterior leg starting from base of toes and extending up the leg
Submerge the pre-prepared dry stirrup splint in water until bubbling stops, then remove
Squeeze, smooth and apply above halfway up calf, under ankle and to above midcalf
Turn back padding around distal and proximal margins of plaster
Apply crepe bandage firmly over slab and fasten with tape
Gently mould plaster to patient anatomy maintaining position until hardened
Post-procedure care
Check X-ray, circulation and limb function:
Confirm fracture reduction with post-procedure X-ray
Check capillary refill and comfort (loosen crepe bandage or re-splint if required)
Check plaster is in correct position at knee and ankle
Check knee and toe movements are unrestricted
Provide plaster care instructions:
Patient is instructed not to weightbear
Elevate limb when possible (decreases pain and swelling)
Avoid applying pressure and heat to the cast
Do not wet the plaster (use plastic bag to protect plaster while in shower)
Return for assessment if damaged cast, increasing pain, numbness or skin colour changes
Provide temporary cast plaster care patient fact sheet
Tips
Proximal margin must be distal to fibula head to avoid compression of common peroneal nerve
Avoid crossing ankle joint anteriorly with the stirrup (creating a circumferential cast)
Temporary casting of open fractures requires covering open wounds with saline-moistened sterile gauze
Always use clean cold water (avoiding thermal injury and allowing for 10 minutes moulding time)
Extra padding at bony prominences avoids pressure areas (femoral condyles, fibular head and malleoli)
All backslabs are temporary requiring definitive management after two weeks (e.g. full cast)
Discussion
There are a variety of splinting techniques in common emergency department practice. Indications for specific casts and recommended methods of application may vary depending on your institution. If in doubt seek local advice from an experienced provider or discuss with your orthopaedic team.
Peer review
This guideline has been reviewed and approved by the following expert groups:
Emergency Care Institute
Please direct feedback for this procedure to ACI-ECIs@health.nsw.gov.au.
References
NSW Agency for Clinical Innovation. Orthopaedic/musculoskeletal. Sydney: ACI; 2020. Available from https://www.aci.health.nsw.gov.au/networks/eci/clinical/clinical-resources/clinical-tools/orthopaedic-and-musculoskeletal
Roberts JR, Custalow CB, Thomsen TW. Roberts and Hedges’ clinical procedures in emergency medicine and acute care. 7th ed. Philadelphia, PA: Elsevier; 2019.
Dunn RJ, Borland M, O’Brien D (eds.). The emergency medicine manual. Online ed. Tennyson, SA: Venom Publishing; 2019.
Eiff MP, Hatch R. Fracture management for primary care. 3rd ed. Philadelphia PA: Saunders; 2011.
Stracciolini A. Basic techniques for splinting of musculoskeletal injuries In: UpToDate. Waltham (MA): UpToDate. 2019 April 18. Available from: https://www.uptodate.com/contents/basic-techniques-for-splinting-of-musculoskeletal-injuries
Liverpool hospital emergency department: Plaster booklet (2019)