Splinting and hand therapy

In short

Splinting is the fabrication and application of an external device (orthosis) to the hand, wrist or forearm to immobilise, mobilise, restrict or support tissue, while hand therapy is the specialised rehabilitation of upper-limb injury and disease using exercise, oedema and scar management, sensory re-education, splinting and graded occupation. Occupational therapists are the primary fabricators of custom low-temperature thermoplastic hand splints in India and work alongside plastic and orthopaedic surgeons in post-surgical hand protocols. The topic is examined in BOT papers on OT process and methods, OT in orthopaedic and surgical conditions, and biomechanics, and appears in viva stations on splint identification, purpose and precautions. It is used daily in hand units at AIIMS, CMC Vellore, Ganga Hospital Coimbatore, Sancheti and Safdarjung burns units, and in industrial and leprosy rehabilitation. Hand therapy also drives return-to-work certification under the Rights of Persons with Disabilities Act, 2016 disability assessment of upper-limb impairment.

Explained

Definitions and terminology

• Splint - a temporary or custom external device applied to a body segment to immobilise, support, protect, mobilise or correct. Orthosis is the broader, preferred ISO/professional term; "splint" is retained in hand therapy usage.
• ASHT (American Society of Hand Therapists) Splint Classification System (SCS) nomenclature names: articulation(s) included, direction of force, purpose (immobilisation / mobilisation / restriction / torque-transmission) and number of secondary joints — e.g. "index-middle MCP flexion mobilisation orthosis, type 1".
• ISO 8549 / ISO 9999 naming uses anatomical abbreviations: HO (hand orthosis), WHO (wrist-hand orthosis), WHFO (wrist-hand-finger orthosis), EWHO (elbow-wrist-hand orthosis).
• Static - no moving parts, holds a position. Serial static - remoulded repeatedly at the end of available range to lengthen tissue. Static progressive - inelastic component (screw, turnbuckle, MERiT, Velcro tab) adjusted to hold tissue at end range. Dynamic - elastic traction (outrigger with rubber band, spring wire) applying continuous low load through moving range.
• Prophylactic / preventive (prevents deformity, e.g. resting hand splint in rheumatoid arthritis), corrective (reduces an existing contracture), substitutive/functional (replaces lost motor function, e.g. radial nerve dynamic extension splint), protective (post-tendon repair dorsal blocking).
• Prehension patterns assessed before splinting: power grip (cylindrical, spherical, hook), precision grip (pad-to-pad pinch, tip pinch, lateral/key pinch, three-jaw chuck).

Biomechanics and design principles

• Three-point pressure principle: every splint works through one force at the deforming point and two counter-forces on either side; the middle force is equal and opposite to the sum of the two end forces.
• Pressure = Force / Area — widen and lengthen the splint and flare its edges to cut pressure; never reduce force to a level that stops doing the job.
• Mechanical advantage: lengthen the lever arm (two-thirds of forearm length for a forearm trough, half of its circumference in width) to reduce unit pressure.
• 90° angle of pull rule: the dynamic traction line must meet the mobilised bone at 90°; otherwise the force resolves into a joint-compressing or distracting component instead of rotation.
• Low load prolonged stress (LLPS) remodels collagen better than brief high force — dynamic traction of roughly 100–300 g per finger, pain-free, worn for long periods; total end range time (TERT) is the governing dose concept.
• Torque = force × perpendicular distance; two splints with the same spring may deliver very different torque if the outrigger height differs.
• Preserve arches: longitudinal arch, proximal and distal transverse arch; a flat splint that obliterates the distal transverse arch destroys grasp.
• Respect creases: the distal palmar crease, thenar crease and wrist crease must be free if the joint beneath must move.
• Safe position (antideformity / functional position): wrist 20–30° extension, MCP 70–90° flexion, IP near extension, thumb abducted and opposed — used for burns and resting splints to counter the claw-collapse pattern.
• Position of immobilisation after fracture or oedema differs from the position of comfort (wrist flexion, MCP extension), which must be avoided because it shortens collateral ligaments and volar plate.

Materials, fabrication steps and precautions

• Low-temperature thermoplastics (LTTP) — polycaprolactone-based sheets (1.6, 2.4, 3.2 mm) soften at about 60–70 °C in a hydrocollator/splint pan, mould directly on skin, and are the standard OT material: coated (non-stick), uncoated (self-bonding), perforated (ventilation), with memory or drape-dominant.
• High-temperature plastics (polypropylene, subortholen) need an oven and a plaster positive; these are orthotist/P&O work, not bedside OT fabrication.
• Plaster of Paris remains the cheapest serial static medium in Indian district settings; aluminium–foam malleable splints are used for simple finger immobilisation.
• Prefabricated splints — cock-up wrist splint, thumb spica, finger extension (Capener/safety-pin), mallet finger (Stack) splint — fast and cheap but poorly fitting on oedematous or atypical hands.
• Fabrication sequence: 1) assess and set the goal and the exact joints to include; 2) take a paper/towel pattern and check it on the sound hand; 3) trace and cut the softened sheet; 4) mould with the palm of the therapist's hand (not fingertips — they leave dents); 5) flare edges and set the arches; 6) cool fully before strapping; 7) attach straps over bony prominences with a wide soft strap; 8) check fit, blanching and function; 9) teach wear schedule and precautions; 10) review within 24–72 hours.
• Precautions: test water temperature; avoid moulding directly over an insensate hand without padding checks; never pad first and mould over padding (reduces volume, increases pressure); watch ulnar styloid, radial styloid, pisiform, MCP heads, first web space; warn about reddening lasting over 20 minutes.
• Wear schedule documented explicitly: continuous, night-only, or on-off hourly; a dynamic splint is typically worn 6–8 hours daily in several sessions, serial static often at night.

Common splints and their indications

• Volar wrist cock-up (WHO), wrist 0–30° extension: carpal tunnel syndrome (night, neutral 0–5°), wrist sprain, radial nerve palsy support, de Quervain adjunct.
• Resting hand / paddle splint (WHFO): rheumatoid arthritis flare, burns, post-CVA hand, tenosynovitis — held in safe position.
• Thumb spica (short/long): de Quervain tenosynovitis, scaphoid injury, first CMC osteoarthritis, ulnar collateral ligament injury of thumb MCP.
• Dorsal blocking splint: flexor tendon repair (wrist neutral to 20° flexion, MCP 50–70° flexion, IP extension) and after volar PIP dislocation.
• Finger-based splints: mallet finger (DIP extension 6–8 weeks), swan-neck/figure-of-eight (blocks PIP hyperextension), buddy strapping, PIP extension serial casting for flexion contracture.
• Nerve injury splints: radial nerve — dynamic MCP extension outrigger or wrist cock-up; median nerve — C-bar / opponens splint to prevent first web contracture and allow opposition; ulnar nerve — anti-claw (Zancolli/knuckle bender/figure-of-eight) splint blocking MCP hyperextension so extrinsic extensors act on IP joints.
• Spasticity splints: volar/dorsal resting splint, cone splint, thumb abduction supinator strap; reflex-inhibiting positions, worn intermittently with tone monitoring.
• Functional/assistive: universal cuff, wrist-driven flexor-hinge (tenodesis) orthosis for C6 tetraplegia, writing splints, tool-holding splints.

Hand therapy: assessment and intervention

• Assessment battery: history and hand dominance; wound and scar; oedema by figure-of-eight tape or volumeter (compare with contralateral; difference above about 10 ml is significant); ROM by goniometry with TAM (total active motion = MCP+PIP+DIP flexion − extension deficits; normal ≈ 260°) and TPM; grip by Jamar dynamometer (second handle position) and pinch by pinch gauge, three trials averaged; sensation by Semmes-Weinstein monofilaments, static/moving two-point discrimination (normal ≤ 6 mm fingertip), Moberg pick-up test for median nerve; dexterity by nine-hole peg, Purdue Pegboard, Jebsen-Taylor, Minnesota; function and participation by DASH/QuickDASH, Michigan Hand Questionnaire, COPM; Kapandji opposition score (0–10) for thumb.
• Oedema management: elevation, retrograde massage, Coban self-adherent wrap, compression glove, contrast baths, active pumping exercise, kinesiology taping; avoid aggressive measures in acute CRPS.
• Scar management: silicone gel sheet, pressure (24 mmHg range), scar massage after epithelialisation, ultrasound, paraffin wax before stretch.
• Exercise: tendon gliding exercises (hook, straight, full fist, tabletop), blocking exercises for selective glide, place-and-hold, differential tendon glide (FDP vs FDS), intrinsic/extrinsic stretch, nerve gliding, graded strengthening with therapy putty, hand-grip exerciser and work-simulated tasks.
• Flexor tendon repair protocols: immobilisation (3 weeks, non-compliant or paediatric), early passive mobilisation — Duran–Houser controlled passive glide and Kleinert dynamic rubber-band traction within a dorsal blocking splint — and early active mobilisation/place-and-hold where a four- or six-strand repair permits. Light resistance from about 6 weeks, full function at about 12 weeks; the "no passive extension, no resisted flexion" rule governs the first 3–4 weeks.
• Extensor tendon repair by Verdan zones: zones I–II mallet pattern (static DIP extension), zones III–IV (boutonnière, PIP extension splint), zones V–VIII dynamic extension with controlled flexion.
• Replantation, crush and burn hands: earliest safe splinting in antideformity position, wound-dictated timing, desensitisation and mirror therapy for pain, sensory re-education in nerve repair, and graded return to occupation.
• Sensory re-education phases: protective sensation education first (insensate hand precautions — the core of leprosy and diabetic hand care), then localisation, then discrimination with varied textures, eyes closed then open.

Indian practice, regulation and service context

• Occupational therapists in India are registered under the National Commission for Allied and Healthcare Professions Act, 2021, which created the NCAHP and State Allied and Healthcare Councils; occupational therapy is a recognised profession under its Schedule, and professional standards and the central register sit with the Commission (earlier the AIOTA voluntary register). Curriculum norms for BOT come through the Commission and the affiliating university.
• Rights of Persons with Disabilities Act, 2016 and the 2018 Guidelines for Assessment of Disability govern permanent-physical-impairment certification; upper-limb and hand impairment is computed from loss of prehension, sensation and strength, and OT reports feed that assessment.
• Assistive device supply schemes: ADIP scheme of the Department of Empowerment of Persons with Disabilities (DEPwD), ALIMCO manufacture of orthoses, CGHS/ESIC and Ayushman Bharat PM-JAY packages covering splinting and rehabilitation in empanelled hospitals; state insurance packages list hand splints at modest rates.
• National Leprosy Eradication Programme supplies MCR (microcellular rubber) footwear and splints and teaches self-care for insensate hands — a major Indian splinting workload; National Programme for Prevention and Control of NCDs covers diabetic hand and stroke rehabilitation.
• Workplace injury: occupational hand injury rehabilitation and employer duties now sit under the four Labour Codes in force from 21 November 2025 (the Occupational Safety, Health and Working Conditions Code, 2020 and the Code on Social Security, 2020 replaced the Factories Act and the Employees' Compensation Act provisions); ESIC hospitals run hand therapy and vocational rehabilitation.
• Costs (indicative, vary widely): LTTP sheet roughly ₹2,500–6,000 per 18"×24" sheet, so a custom wrist splint costs about ₹400–1,200 in material and is charged about ₹800–3,000 in private units; prefabricated wrist splints retail at about ₹300–900. GST on orthopaedic appliances and splints is in the lower slab for notified assistive devices — confirm the current rate for the specific HSN before quoting.

Key points

• Splint - external device to immobilise, mobilise, restrict or transmit torque; orthosis is the formal term.
• Three-point pressure - one force at the deformity, two counter-forces; all splints obey it.
• Pressure = F/A - lengthen, widen and flare, do not just pad, to reduce pressure sores.
• Safe/antideformity position - wrist 20–30° ext, MCP 70–90° flex, IP extended, thumb abducted and opposed.
• Position of comfort is the position of deformity - wrist flexion with MCP extension must be avoided.
• Static vs serial static vs static progressive vs dynamic - no motion, remoulded, inelastic adjustable, elastic traction.
• LLPS and TERT - low load held for long total end-range time remodels collagen; high force causes inflammation.
• 90° angle of pull - dynamic traction perpendicular to the segment, else joint compression or distraction.
• Two-thirds rule - forearm trough covers two-thirds of forearm length and one-half of its circumference.
• Dorsal blocking splint - after flexor tendon repair; wrist neutral–20° flexion, MCP 50–70° flexion, IP straight.
• Anti-claw (ulnar palsy) splint - blocks MCP hyperextension so long extensors extend the IP joints.
• Opponens/C-bar splint - median palsy; prevents first web contracture and positions thumb for pinch.
• TAM - sum of MCP, PIP and DIP active flexion minus extension deficits; normal about 260° per finger.
• Two-point discrimination - normal fingertip ≤ 6 mm; above 15 mm means protective sensation only.
• Jamar dynamometer - second handle position, three trials averaged, compare with contralateral hand.
• Kapandji score - 0–10 thumb opposition grading against fixed anatomical landmarks.
• Duran = controlled passive glide; Kleinert = dynamic traction - both inside a dorsal blocking splint.
• NCAHP Act, 2021 and RPwD Act, 2016 - the regulatory and certification framework for Indian OT practice.

Formulas and examples

Example 1 — unit pressure under a strap. A wrist splint strap applies 20 N over a 1 cm × 2 cm area, i.e. 2 cm² = 2 × 10⁻⁴ m².

• P = 20 / 2 × 10⁻⁴ = 100,000 Pa = 100 kPa = 10 N/cm².
• Replace it with a 2.5 cm × 4 cm strap: A = 10 cm² = 1 × 10⁻³ m² → P = 20 / 1 × 10⁻³ = 20,000 Pa = 20 kPa, a five-fold reduction in unit pressure for exactly the same holding force. This is why wide soft straps are used over the ulnar styloid.

Example 2 — three-point force equilibrium in a PIP extension splint. The splint presses 6 N dorsally over the proximal phalanx and 4 N dorsally over the middle phalanx.

• The volar counter-force at the PIP joint = 6 + 4 = 10 N (ΣF = 0).
• Checking moments about the PIP axis: if the proximal pad sits 3 cm proximal and the distal pad 2 cm distal, moments are 6 × 3 = 18 N·cm and 4 × 2 = 8 N·cm — unequal, so the splint would slide distally; moving the proximal pad to 1.33 cm (6 × 1.33 ≈ 8 N·cm) or increasing the distal pad force to 6 N at 3 cm balances the system.

Example 3 — torque and outrigger height. A dynamic PIP flexion splint uses 200 g of traction with the finger loop 4 cm from the PIP axis.

• Convert: 200 g = 0.200 kg → F = 0.200 × 9.81 = 1.962 N; d = 0.04 m.
• T = 1.962 × 0.04 = 0.0785 N·m ≈ 78.5 N·mm (800 g·cm).
• If the outrigger is dropped so the moment arm becomes 2 cm, T = 1.962 × 0.02 = 0.0392 N·m — half the torque from the same rubber band. To restore 0.0785 N·m at 2 cm the traction must double to about 400 g, which may exceed the comfortable LLPS range.
• Angle check: if the line of pull is 30° off perpendicular, rotatory component = 1.962 × cos 30° = 1.70 N (87%) and the joint-compressing component = 1.962 × sin 30° = 0.98 N — half the applied force diverted into the joint surface, with 13% of the rotatory effect lost.

Example 4 — TAM and outcome grading. Index finger, 8 weeks after zone II flexor repair: active flexion MCP 80°, PIP 85°, DIP 50°; extension deficits MCP 0°, PIP 20°, DIP 10°.

• Flexion sum = 80 + 85 + 50 = 215°; deficit sum = 0 + 20 + 10 = 30°.
• TAM = 215 − 30 = 185°.
• Uninvolved index TAM = 260° → %TAM = 185/260 × 100 = 71.2% — in the Strickland-type scheme this is a *good* rather than excellent result; the 20° PIP extension deficit is the target, so a serial static or static progressive PIP extension orthosis is added at night with continued blocking exercises by day.

Example 5 — oedema measurement. Volumeter readings: injured hand displaces 505 ml, uninjured 440 ml.

• Difference = 65 ml; % difference = 65/440 × 100 = 14.8% — well above the 10 ml / ~10% threshold, so oedema is clinically significant.
• After two weeks of Coban wrap, elevation, retrograde massage and active pumping the injured hand measures 462 ml → difference 22 ml (5.0%), a 43 ml reduction; the compression glove is tapered to night-only wear.

Where it is used

• Hand and plastic surgery units: post-flexor/extensor tendon repair, replantation and crush-injury protocols at CMC Vellore, Ganga Hospital Coimbatore, AIIMS, PGIMER, Sir Ganga Ram, Sancheti Pune — OTs fabricate dorsal blocking and dynamic splints to surgeon protocol.
• Burns units: antideformity splinting, pressure garments and scar management at Safdarjung, KEM Mumbai and state medical college burns wards; splinting starts in the acute phase.
• Rheumatology and orthopaedics OPD: resting hand splints, thumb CMC splints, wrist supports for RA, osteoarthritis, de Quervain and carpal tunnel syndrome.
• Neuro-rehabilitation: post-stroke, traumatic brain injury and spinal cord injury hand positioning; wrist-driven tenodesis orthoses for C6 tetraplegia at ISIC Delhi, NIEPMD Chennai, NILD Kolkata, SVNIRTAR Cuttack.
• Leprosy and diabetic foot/hand programmes: insensate-hand self-care, MCR footwear and night splints under NLEP; large NGO networks (The Leprosy Mission, Bombay Leprosy Project).
• Industrial and occupational health: ESIC hospitals, factory medical centres and corporate ergonomics roles — repetitive strain and crush-injury rehabilitation, work conditioning and return-to-work certification; private hand therapy clinics and orthotic retail (ALIMCO, Tynor, Vissco product fitting).

Interview questions

• Q: What is the difference between a static and a dynamic splint? A: A static splint has no moving parts and holds a position to rest, protect or support; a dynamic splint uses elastic traction through an outrigger to apply continuous low-load force while permitting motion, used for mobilising stiff joints or substituting lost muscle action.
• Q: State the three-point pressure principle. A: Every splint applies one force over the deforming segment and two opposing counter-forces proximal and distal to it; the middle force equals the sum of the two end forces, so lengthening the lever arms lowers the force each pad must exert.
• Q: What is the safe or antideformity position and why is it used in burns? A: Wrist in 20–30° extension, MCP in 70–90° flexion, IP joints near extension and thumb abducted and opposed. It keeps the collateral ligaments and volar plate at length, so the hand does not collapse into the claw pattern as scar contracts.
• Q: Why must a dynamic traction line meet the bone at 90°? A: Only the perpendicular component creates rotation; any deviation resolves part of the force into joint compression or distraction, which is wasted and can damage the joint surface.
• Q: How much force should a dynamic finger splint apply? A: Low load prolonged stress — roughly 100–300 g per finger, always pain-free and without reddening that lasts beyond about 20 minutes; outcome depends on total end range time, not on force magnitude.
• Q: Describe the splint used after a zone II flexor tendon repair. A: A dorsal blocking WHFO with the wrist from neutral to about 20° flexion, MCP in 50–70° flexion and the IP joints in extension, worn continuously for 3–4 weeks; the protocol allows controlled passive or place-and-hold flexion but no passive extension or resisted flexion.
• Q: Differentiate the Duran and Kleinert protocols. A: Both work inside a dorsal blocking splint; Duran–Houser uses therapist- or patient-guided controlled passive flexion and extension of each IP joint to produce differential tendon glide, while Kleinert adds a rubber-band dynamic traction that passively flexes the finger and lets the patient extend actively against it.
• Q: Why is an anti-claw splint effective in ulnar nerve palsy? A: Loss of the interossei and lumbricals lets the long extensors hyperextend the MCP joints so their pull never reaches the IP joints; blocking MCP hyperextension redirects extensor force distally and restores IP extension and a usable grasp.
• Q: What is TAM and how do you interpret it? A: Total Active Motion is the sum of active MCP, PIP and DIP flexion minus the sum of extension deficits, with normal around 260° per finger; expressed as a percentage of the uninvolved finger it grades tendon repair outcome.
• Q: Should you pad a splint before moulding it? A: No — padding is added after moulding and the plastic is moulded to allow for it, because moulding over padding reduces internal volume and increases pressure once the padding compresses.
• Q: How do you decide between a prefabricated and a custom splint? A: Prefabricated is acceptable when the hand is of typical shape, oedema is minimal, the goal is simple support and cost or time is critical; a custom LTTP splint is needed for oedematous, deformed or insensate hands, precise joint positions and post-surgical protocols.
• Q: What are the key precautions when splinting an insensate hand in leprosy or diabetes? A: The patient cannot report pressure pain, so use wide straps and generous contact area, inspect the skin at every visit, start with very short wear periods, teach daily self-inspection, and never rely on the patient's pain report to judge fit.

Common mistakes

• Writing "position of comfort" (wrist flexed, MCP extended) as the resting position — it is the position of deformity and leads to the claw hand.
• Padding a bony prominence and then moulding over it, or adding thick padding to an already snug splint, which raises rather than lowers pressure.
• Confusing static progressive with dynamic — both mobilise, but static progressive uses an inelastic adjustable component and holds a fixed end range.
• Ignoring the distal palmar and thenar creases, so the splint blocks MCP flexion or thumb opposition and the patient abandons it.
• Calculating TAM as the flexion sum alone and forgetting to subtract extension deficits, or comparing it with a textbook 260° instead of the patient's uninvolved hand.
• Prescribing a splint without a written wear schedule, exercise programme and review date — the splint then becomes a cause of stiffness rather than a treatment.
• In vivas, naming a splint by brand or shape only; the expected answer names joints included, position in degrees, purpose and the diagnosis it suits.

Related topics

• Orthotics and prosthetics · Occupational therapy assessment and activity analysis · Activities of daily living and therapeutic activities · OT in orthopaedic and musculoskeletal conditions · Peripheral nerve injuries and neuro-rehabilitation · Biomechanics and kinesiology of the upper limb