Casting and Splinting - Q&A Based on KMTC (Orthopaedic and Trauma Medicine)

SECTION 1: DEFINITIONS AND BASIC CONCEPTS

• A cast is a circumferential rigid immobilization device that completely surrounds the extremity. It provides maximum immobilization but does not accommodate swelling.
• A splint (backslab) is a non-circumferential immobilization device that covers only part of the extremity's circumference. It is preferred in acute injuries because it accommodates swelling, reducing the risk of compartment syndrome.

Key rule: Splints are preferred in the acute/emergency setting; casts are used for definitive management once swelling has subsided.

1. Fracture immobilization (definitive management)
2. Post-operative immobilization
3. Correction of deformities (e.g., congenital talipes equinovarus)
4. Protection of soft tissue repairs (tendon/ligament)
5. Immobilization after closed reduction of fractures

1. Acute fractures (especially where swelling is expected)
2. Sprains and strains
3. Dislocations (after reduction)
4. Tendon and ligament injuries
5. Infections of the hand/extremity requiring periodic wound inspection
6. Pre-operative stabilization
7. As a temporary measure before definitive casting

1. Compartment syndrome or suspected compartment syndrome
2. Severe/uncontrolled swelling
3. Open or infected wounds (relative contraindication - splinting preferred)
4. Vascular compromise
5. Burns over the affected area
6. Skin conditions that may worsen under a cast (e.g., active dermatitis)

SECTION 2: MATERIALS

KMTC exam tip: POP is preferred for initial molding and reductions due to its superior moldability. Fiberglass is preferred for long-term, ambulatory casts.

1. Stockinette - cotton tubular material placed directly on skin; provides a smooth base and protects skin at the edges
2. Cast padding (Webril/cotton wool) - soft padding layer to protect bony prominences and cushion the extremity; applied in overlapping circular fashion
3. Casting/splinting material - POP or fiberglass
4. Elastic bandage (crepe/Ace bandage) - used over splints to secure them; NOT used tightly over casts

• Upper extremity splints: 8 layers of plaster
• Lower extremity splints: 12-15 layers of plaster (up to 20 layers in obese patients)
• More layers = more strength, but also more heat generated and more weight/discomfort.

Using more than 12 sheets significantly increases burn risk, especially with hot dipping water or extra-fast-setting plaster. - Roberts and Hedges' Clinical Procedures in Emergency Medicine

SECTION 3: PRINCIPLES OF APPLICATION

• Explain the procedure; cover clothing to protect from water and plaster.
• Remove rings, watches, and jewelry from the affected extremity.

• Roll stockinette over the extremity, extending 5-8 cm beyond the intended cast margins on both ends.

• Wrap cast padding from distal to proximal in a spiral manner, overlapping each layer by 50%.
• Apply extra padding over bony prominences (malleoli, olecranon, fibular head, heel).

• Cut the appropriate number of plaster strips to the required length.
• Submerge completely in cool, clean water (approximately 24°C) until bubbling stops.
• Remove and gently squeeze (do NOT wring) to remove excess water - aim for wet and sloppy consistency.
• Smooth the wet plaster on a flat surface to laminate the layers.

• Position the splint over the padding.
• Fold back the stockinette ends to cover the plaster edges.
• Secure with elastic bandage wrapped distal to proximal.

• Mold with the palms of the hands (never fingers - to avoid pressure ridges).
• Position the extremity in the correct anatomical/functional position.
• Complete all molding before the plaster reaches a creamy (critical period) consistency.

• F - Function (movement of fingers/toes)
• A - Arterial pulse
• C - Capillary refill
• T - Temperature of skin
• S - Sensation

SECTION 4: SPECIFIC SPLINTS AND CASTS

• Ankle sprains
• Stable ankle/distal tibia-fibula fractures
• Achilles tendon injuries
• Foot fractures

• Use 4- or 6-inch wide plaster strips
• Extend from the plantar surface of the metatarsal heads along the posterior aspect of the leg to just below the fibular head
• Apply 15-20 layers if partial weight bearing is expected
• Easiest application: patient prone with knee flexed at 90° and ankle at 90°

• Carpal fractures (e.g., non-displaced scaphoid fracture)
• Wrist sprains
• Wrist tendinopathies (e.g., de Quervain's)
• Distal radius fractures (non-displaced)

• Apply from the mid-palm to the proximal forearm
• 8 layers of plaster
• Secure with elastic bandage

• Wrist: 10-20 degrees of extension
• MCP joints: 50-60 degrees of flexion
• PIP and DIP joints: 5-10 degrees of flexion (slight flexion)
• Thumb: abducted away from the palm

• MCP joints: 90 degrees of flexion
• IP joints: fully extended

• Scaphoid fracture (suspected or confirmed)
• Skier's thumb (gamekeeper's thumb - ulnar collateral ligament injury)
• Thumb fractures and dislocations
• De Quervain's tenosynovitis

SECTION 5: COMPLICATIONS

1. Thermal burns - from exothermic plaster reaction, especially with hot water or thick splints
2. Compartment syndrome - from circumferential casting when swelling is present; presents with the 5 P's (Pain, Pallor, Pulselessness, Paraesthesia, Paralysis)
3. Pressure sores/skin breakdown - from inadequate padding over bony prominences
4. Neurovascular compromise - from tight application

1. Pain - disproportionate to injury, worsened by passive stretch of muscles in the compartment
2. Pressure - tight, tense feeling
3. Paraesthesia - tingling/numbness (early nerve ischaemia)
4. Pallor - pale skin
5. Pulselessness/Paralysis - late signs indicating serious ischaemia

• Immediately bivalve or remove the cast
• Elevation of the extremity (but NOT above heart level - this reduces arterial flow)
• Emergency fasciotomy if compartment pressure > 30 mmHg or within 30 mmHg of diastolic BP

1. Use cool, clean water (~24°C) - never hot water
2. Do not use more than 12 layers of plaster
3. Avoid extra-fast-setting plaster where possible
4. Do not place pillows, blankets, or other insulating materials around the extremity while the plaster is setting
5. Use fresh water for each patient - do not reuse
6. Allow the extremity to set in open air

SECTION 6: SPECIFIC TYPES OF CASTS

The long arm cast prevents forearm rotation (pronation/supination) which is important for fractures of the radial/ulnar shafts.

SECTION 7: CAST REMOVAL AND CARE

• A cast saw (oscillating saw) is used - it cuts hard cast material but does NOT cut skin because it oscillates rather than rotates
• The saw is run along each side of the cast
• A cast spreader is then used to open the cast
• Bandage scissors are used to cut through the padding
• Always hold the cast saw at an angle and move it in a series of short strokes, lifting completely off the skin between strokes

1. Elevate the limb above the level of the heart for 24-48 hours to reduce swelling
2. Do not get the cast wet (POP) - use a waterproof cover when bathing
3. Do not insert objects under the cast to scratch itches
4. Report immediately if: increasing pain, numbness, tingling, pallor, coldness, or difficulty moving fingers/toes
5. Keep the cast clean and dry
6. Return for follow-up as advised
7. Do not bear weight unless instructed to do so
8. The cast may feel warm as it sets - this is normal

SECTION 8: IMMOBILIZATION PERIODS

• Roberts and Hedges' Clinical Procedures in Emergency Medicine; Pfenninger and Fowler's Procedures for Primary Care

SECTION 9: SHORT-ANSWER AND MCQ STYLE

• F - Function (active movement of fingers/toes)
• A - Arterial pulse
• C - Capillary refill (<2 seconds)
• T - Temperature of skin
• S - Sensation

• Humeral shaft fractures (as initial immobilization)
• It is often replaced by a functional brace after 10-14 days once the initial swelling subsides

• Roberts and Hedges' Clinical Procedures in Emergency Medicine, Chapter 50
• Pfenninger and Fowler's Procedures for Primary Care, Chapter on Casting and Splinting
• Rockwood and Green's Fractures in Adults, 10th ed.

Clinical Images: Proper Cast and Splint Application Techniques

1. Plaster Splint Application - Alternative (Sandwich) Method

• Step 1-2: Soak plaster, measure Webril to same length; lay 3-4 Webril layers flat, place smoothed plaster on top
• Step 3: Add final Webril layer on top (plaster is "sandwiched")
• Step 4: Apply whole assembly to extremity with assistant holding
• Step 5: Secure with elastic bandage distal to proximal, fold stockinette over edges
• Step 6: Mold with palms only - position the extremity, gently mold to body contours

2. Prefabricated Fiberglass Splint Application - 10-Step Guide

1. Measure splint length against the area to be splinted
2. Cut to length with trauma shears - round the corners to avoid sharp fiberglass edges
3. Stretch cotton padding several inches beyond fiberglass on both ends (no fiberglass contacts skin)
4. Wet the fiberglass: run tap water over it until water exits the bottom; wring out excess
5. Apply to extremity; fold stockinette edges over splint to hold in place
6. Secure with elastic bandage wrapped distal to proximal
7. For hand splints: cut a hole in the elastic bandage at the thumb loop region
8. Bring thumb through the hole - reduces bunching in web space, allows thumb mobility
9. Position extremity in desired position and mold with palms (not fingertips - avoids pressure ridges)
10. Post-splint check: observe for vascular compromise or increasing pain; loosen elastic if either occurs

3. Lower Extremity Splint - Clinical Application

• Top left: Measuring plaster strip length against the limb
• Top right: Applying the stockinette with the foot incorporated and toes left exposed
• Bottom left: Applying/smoothing the plaster slab over the padding
• Bottom right: Securing with elastic bandage, ankle maintained at 90 degrees (neutral position)

Key teaching point: The ankle must be held at 90° throughout application. The easiest way is the prone position with the knee flexed at 90° - gravity naturally maintains ankle dorsiflexion.

4. Long Arm Cast - Step-by-Step

1. Apply stockinette - rolled over the entire length of the extremity, extending beyond cast margins
2. Apply padding (Webril) - overlapping spiral wrap, extra layers over bony prominences
3. Apply cast tape - circumferential wrapping, distal to proximal

5. Hand Position of Function (Wineglass Position)

6. U-Splint (Stirrup / Sugar-Tong) - Ankle

• Left: Diagram of U-splint placement - runs under the plantar surface of the foot and extends up both the medial and lateral sides of the lower leg to just below the fibular head
• Right: Pre- and post-reduction X-rays showing ankle dislocation - confirms this splint is used for post-reduction stabilization of ankle dislocations and distal tibia/fibula fractures
• Key point: Ankle held at 90°; U-splint can be combined with a posterior splint for both AP and mediolateral stability

7. Clinical Orthopaedic Setting - Cast/Splint Rooms

Summary: Key Visual Teaching Points

• Roberts and Hedges' Clinical Procedures in Emergency Medicine, Chapter 50 (Splinting Techniques)

KMTC Casting & Splinting - Exam Practice Paper

SECTION ONE: MULTIPLE CHOICE QUESTIONS (MCQs)

SECTION TWO: TRUE OR FALSE

SECTION THREE: SHORT ANSWER QUESTIONS (SAQs)

1. Compartment syndrome - Increased pressure in muscle compartments from swelling constrained by a circumferential cast; can cause permanent ischaemia if not relieved
2. Thermal burns - From exothermic plaster setting reaction, especially with hot water, thick plaster (>12 layers), or insulating pillows during setting
3. Pressure sores/skin breakdown - From inadequate padding over bony prominences (malleoli, olecranon, heel)
4. Infection - Bacterial/fungal growth in the warm, moist, dark environment under the cast; toxic shock syndrome has been rarely reported
5. Joint stiffness - Invariable consequence of prolonged immobilization; ranges from mild to severe contracture
6. DVT (Deep Vein Thrombosis) - Particularly in lower limb casts due to immobility and venous stasis

1. Prepare patient - Explain procedure; remove footwear and socks; protect clothing
2. Apply stockinette - Roll over the entire foot and lower leg, extending beyond intended margins
3. Apply padding (Webril) - Distal to proximal spiral wrap; extra layers at heel, malleoli, and fibular head
4. Prepare plaster - Cut 4-6 inch strips to appropriate length (from metatarsal heads to fibular head posteriorly); use 12-15 layers; submerge in cool water, remove when bubbling stops, squeeze gently
5. Smooth plaster - Lay flat on surface and laminate; remove wrinkles
6. Apply to limb - Position on posterior leg; fold stockinette back over edges
7. Secure - Wrap with elastic bandage distal to proximal
8. Position and mold - Maintain ankle at 90° (neutral dorsiflexion); mold with palms around malleoli and heel
9. Post-check (FACTS) - Verify circulation, sensation, movement of toes; instruct on elevation and signs of complications

1. Elevation - Keep the limb elevated above heart level for 48 hours to reduce swelling
2. Keep dry - Do not wet the cast (for POP); use a waterproof cover/plastic bag when bathing
3. No foreign objects - Never insert objects (pencils, sticks) under the cast to relieve itching
4. Warning signs - Return to hospital IMMEDIATELY if: increasing pain, numbness/tingling, pale/cold fingers or toes, difficulty moving fingers/toes, foul smell, or visible cast damage
5. Activity restriction - Do not bear weight unless specifically told to do so
6. Normal sensations - The cast may feel warm as it sets and may have a mild odour - these are normal
7. Follow-up - Return on the specified date for repeat X-ray and cast check
8. Cast care - Do not trim or modify the cast yourself

SECTION FOUR: LONG ANSWER QUESTION (LAQ)

(a) Assessment [5 marks]

1. History - Mechanism of injury, time of injury, hand dominance, allergies, tetanus status, last meal (if surgery anticipated)
2. General examination - Vital signs, level of consciousness, ABCDE approach (check for other injuries)
3. Local examination of the wrist:
   • Look - Deformity ("dinner fork deformity" in Colles' fracture), swelling, bruising, skin integrity (open wound?)
   • Feel - Tenderness at fracture site, neurovascular status (radial pulse, capillary refill <2 sec, sensation in median/ulnar/radial nerve territories)
   • Move - Range of motion (limited by pain), finger movement
4. Radiological assessment - X-ray wrist (AP and lateral views) to confirm fracture type, displacement, and involvement of articular surface
5. Document - Baseline neurovascular status before immobilization

(b) Application of Below-Elbow Backslab [10 marks]

1. Explain the procedure to the patient; obtain consent; cover clothing
2. Remove rings, watches, and jewelry from the right hand
3. Apply stockinette from knuckles to mid-forearm, extending 5 cm beyond each end of the intended splint
4. Apply Webril padding in a distal-to-proximal spiral wrap (50% overlap each turn); apply extra layers at wrist and bony prominences
5. Prepare POP strips - cut 4-inch wide strips to appropriate length (from metacarpal heads to 2 cm below elbow); prepare 8 layers
6. Wet plaster - Submerge fully in cool clean water (~24°C); wait for bubbling to stop; remove and gently squeeze to wet/sloppy consistency (do NOT wring)
7. Smooth plaster on a flat surface to laminate layers and remove wrinkles
8. Apply to volar (palm) surface of forearm; fold back stockinette edges to cover plaster margins
9. Secure with elastic bandage wrapped distal to proximal without undue tension; tape down metal clips
10. Position and mold - Hold wrist in 10-20° of extension (functional position); mold splint with palms along the contour of the forearm; maintain position until plaster hardens
11. Post-splint FACTS check: Function (finger movement), Arterial pulse (radial), Capillary refill (<2 sec), Temperature, Sensation
12. Instruct patient on elevation, signs of complications, and follow-up date (typically 1 week for repeat X-ray)

(c) Complications and Prevention [5 marks]

QUICK REVISION TABLE - High-Yield KMTC Facts

Note on Actual KMTC Exam Papers: The Certificate FQE Casting Paper 1 is available on Scribd (subscription required). The KMTC Department of Orthopaedics also runs weekly CAT quizzes on dknowledge.co.ke every Tuesday - the Casting and Splinting CAT links are active mid-day each week. Real past papers are available via KMTC Library Catalogue and at kenyaplex.com (paid notes, 55 pages, KES 180).