Splinting in Occupational Therapy
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Direct answer
A splint is a removable external support that holds a joint where healing, protection or function needs it held — and choosing it is core occupational therapy craft. Splints divide by movement into static designs that immobilise, dynamic or mobilisation designs with outriggers and elastic components that assist or resist motion, static-progressive designs that hold joints at their achievable end-range using non-elastic parts adjusted over time, and serial static splints remoulded as range improves. Fabrication is mostly custom, from low-temperature thermoplastics softened in a water bath at roughly 60 degrees Celsius, moulded directly on the patient. Every prescription names the joints crossed, the position held, the hours worn and the review date — because a splint worn wrongly is a pressure sore with straps.
What you must remember
- The safe or intrinsic-plus position for hand immobilisation: wrist extended 20-30 degrees, MCP joints flexed about 60-70 degrees, interphalangeal joints fully extended, thumb abducted — the position that keeps the collateral ligaments long and prevents the claw that disuse would create.
- Named splints and their indications: volar cock-up splint for wrist drop (radial palsy) and night use in carpal tunnel syndrome; thumb spica for de Quervain's tenosynovitis and scaphoid injuries; ulnar gutter for boxer's fracture of the fourth and fifth metacarpals; knuckle-bender or Capener spring splint for ulnar claw hand; Stack splint for mallet finger; opponents splint for median nerve palsy; aeroplane splint at 90 degrees-plus shoulder abduction for axillary burns; resting hand splint for rheumatoid flares.
- Dynamic versus static-progressive: dynamic uses elastic traction to move a joint; static-progressive uses inelastic components to hold the end-range gained — the distinction examiners love.
- Serial static: the same splint remoulded every few days as contracture yields, classic after burns and long immobilisation.
- Materials: low-temperature thermoplastics (mouldable at roughly 60 degrees Celsius), plaster of Paris for serial casting, prefabricated options when customisation is impossible.
- Post-fabrication checks: smooth padded edges, straps applying even pressure, sensory check before and after, skin inspection at 20-30 minutes and again at 24-48 hours, and a written wearing schedule.
- Complications of careless splinting: pressure ulcers, nerve compression paraesthesia, joint stiffness and muscle atrophy from over-wearing — hours on skin must be as deliberate as the diagnosis.
Choosing the splint for five ward problems
Reasoning, not recall, picks the splint. First: radial palsy after a humeral fracture — the wrist cannot extend, so finger flexion has no stable base; a volar cock-up splint holds the wrist in about 20 degrees of extension while active finger exercise continues — static support, moving parts none. Second: an ulnar claw from leprosy — MCP joints hyperextend while the interphalangeals flex; the knuckle-bender blocks MCP hyperextension with a spring, letting the extensors straighten the fingers — a dynamic choice. Third: a boxer's fracture — the injured ray and its uninjured neighbour are splinted together; an ulnar gutter holds the fourth and fifth metacarpals with the MCPs flexed, three weeks typically. Fourth: a healing axillary burn — scar contracture would weld the arm to the chest, so an aeroplane splint holds 90 degrees-plus abduction, worn between exercise sessions, never instead of them. Fifth: a rheumatoid hand in flare — a night resting splint in the safe-position variant rests inflamed joints and reduces pain; it does not correct established ulnar drift. Each answer states joints, position, construction and hours — that is the full prescription.
Where students slip
The recurring viva failure is parroting splint names without the indication logic — the examiner simply changes the nerve or the burn site and the candidate collapses. The second is the dynamic versus static-progressive mix-up: elastic components that pull a joint through range are dynamic; inelastic components that hold what was just gained are static-progressive, and their clinical moments differ (flaccid weakness versus resolving stiffness). In the BOT practical, marks vanish on finishing — unpadded edges, straps crossing joints at creases, and the absent wearing schedule are the three standard deductions.
Frequently asked questions
What is the safe position for hand immobilisation?
Wrist extension of 20-30 degrees, MCP flexion of about 60-70 degrees, full interphalangeal extension and thumb abduction — protecting collateral ligament length.
How does a static-progressive splint differ from a dynamic one?
Dynamic splints use elastic traction to move joints through range; static-progressive splints use inelastic components to hold the end-range already achieved, adjusted as range improves.
Which splint suits an ulnar claw hand?
A knuckle-bender or Capener spring splint blocking MCP hyperextension, allowing the long extensors to extend the interphalangeal joints.
Why is the aeroplane splint used in axillary burns?
It holds the shoulder abducted beyond 90 degrees so healing scar cannot contract the arm down to the chest wall, and it is alternated with exercise, not substituted for it.
At what temperature is low-temperature thermoplastic moulded?
Commonly around 60 degrees Celsius in a water bath — warm enough to shape, cool enough to mould directly on the patient.