Synopsis
Apply and monitor casts or splints that maintain alignment without sacrificing skin, nerve, perfusion or compartment safety, and respond immediately when pressure-related warning symptoms appear.
- Before application, confirm indication, reduction target, skin and wound condition, allergy, swelling trajectory and baseline motor, sensory, pulse and capillary findings.
- Use an appropriate splint or backslab during evolving swelling; a circumferential cast requires enough padding, safe moulding and a plan for pressure expansion and review.
- First-line post-application checks are pain, digit colour and warmth, capillary refill, pulse where relevant, named nerve motor and sensory function and ability to move uninjured joints.
- Mould with broad surfaces rather than fingertips, protect bony prominences and cast edges and never insert padding, objects or instruments beneath a finished cast.
- Increasing pain, passive-stretch pain or neurological change requires immediate release of every external constriction and urgent compartment-syndrome assessment; intact pulses are a late and unreliable reassurance.
- Focal cast pressure requires same-day removal or windowing only under an expert plan that still permits full skin inspection and does not create a new edge-pressure point.
- Give written elevation, movement, hygiene, wet-cast, skin, neurovascular and emergency return instructions and verify patient or carer understanding by teach-back.
- Review reduction and fit after swelling changes; a cast can become dangerous when too tight and ineffective when too loose.
Key red flags
Progressive pain despite analgesia or pain on passive stretch under a cast is acute compartment syndrome until urgently assessed.
New numbness, weakness, burning, inability to move digits, coolness, pallor or delayed capillary refill requires immediate cast and neurovascular review.
Focal persistent burning or a patient repeatedly identifying one pressure point can precede a deep cast ulcer even when the outside looks normal.
Wetness, offensive smell, fever, discharge or increasing pain can indicate skin breakdown, wound infection or a foreign object beneath the cast.
A cast that becomes loose after swelling subsides may no longer control reduction and can rub, migrate or permit displacement.
Breathlessness, chest pain or new whole-limb swelling during immobilisation requires assessment for VTE rather than attribution to the cast alone.
Investigation priorities
Detect evolving compartment, nerve, perfusion, skin or fit problems before and after every cast intervention.
Management branches
A fracture, postoperative repair or soft-tissue condition requires immobilisation.
- Confirm indication, position, reduction, expected swelling, skin and wound access and document baseline neurovascular findings.
- Choose splint, backslab or circumferential cast according to stability and swelling, with smooth padding and protected prominences.
- Mould with broad surfaces, avoid constrictive turns and thermal risk and preserve movement of intended free joints.
- Repeat neurovascular examination, obtain required radiographs and write weight-bearing, duration and review instructions.
The patient leaves the casting area or swelling changes during follow-up.
- Give written and demonstrated elevation, digit movement, hygiene, wet-cast, pressure and emergency advice.
- Arrange fracture-specific review of fit, skin, alignment and radiographs as oedema resolves.
- Replace a loose, damaged or wet device rather than accepting rubbing or loss of control.
- Increase surveillance for neuropathy, cognitive impairment, fragile skin or inability to report symptoms.