Paediatric Hip Spica Cast Application

Step 1: Indication Assessment and Spica Type Selection

Decision Making Determine indication: (1) FEMUR FRACTURE <5 years: one-and-a-half spica standard. (2) DDH POST-REDUCTION: bilateral spica, human position (hip flexion 90-110°, abduction 40-50°, internal rotation 10-20°). (3) POST-OPERATIVE (osteotomies, open reduction): as per surgeon preference, typically bilateral spica. Select spica type: SINGLE LEG (rarely used - unstable). ONE-AND-A-HALF (standard for femur fracture - affected leg to toes, unaffected to above knee). BILATERAL (DDH, post-op - both legs included to knees or ankles).

Review x-rays to confirm fracture pattern, displacement, and need for reduction. For DDH, review arthrogram or ultrasound to confirm hip reducible and concentric reduction achievable.

Step 2: Pre-Application Planning and Consent

Patient Assessment Assess patient: age, weight, fracture alignment or hip position required, associated injuries, family support capability. Plan admission vs same-day discharge based on family capability and patient stability.

Consent Discussion (1) Duration typically 6-12 weeks for fracture (younger heals faster), 12 weeks for DDH. (2) Home care requirements: toileting management, bathing restrictions, specialized positioning, car seat requirement. (3) Complications: skin breakdown 5-15%, cast soiling 10-20%, loss of reduction 5-10%, compartment syndrome <1%, SMA syndrome 1-3%. (4) Hospital observation 4-24 hours then home if stable and family capable. (5) Follow-up schedule: 1 week mandatory, then every 2-3 weeks until removal.

Plan general anaesthesia with neuromuscular blockade for fracture reduction and comfortable cast application. Ensure family has arranged specialized car seat (E-Z-On vest or similar) for transportation home.

Step 3: Positioning and Setup on Spica Table

Theatre Setup Under general anaesthesia with neuromuscular blockade, position child SUPINE on spica table. Perineal post well-padded with foam in crotch (supports pelvis during application, prevents sagging). Upper body on padded support with slight head elevation. Arms free, accessible for anaesthesia monitoring.

Organize all supplies within arm's reach before starting: stockinette (6-inch and 4-inch rolls), padding (cast padding or ortho-wool), waterproof barrier material (plastic sheeting, Gore-Tex), fibreglass or plaster rolls (4-inch and 6-inch, estimate 8-12 rolls total), water buckets, waterproof tape, moleskin for petaling, cast scissors, spreaders, gloves. Assistant positioned to support legs and maintain alignment during application.

Alternative if no spica table: flat table with assistant supporting pelvis manually throughout procedure (more challenging but feasible).

Step 4: Fracture Reduction for Femur Fractures

Reduction Technique For FEMUR FRACTURE: Apply longitudinal traction on affected leg (assistant or surgeon pulls from ankle while stabilizing thigh). Correct angulation: typically apex anterior or lateral from muscle pull. Assess rotation: patella should point directly forward when knee at 90° flexion - compare to unaffected side. Use fluoroscopy to confirm reduction AP and lateral views.

Acceptable Alignment ACCEPT: less than 30° anterior angulation (plane of hip motion, remodels well), less than 20° varus or valgus angulation, up to 2-3cm shortening (overgrowth compensates average 1.5-2cm). ZERO tolerance for rotational deformity - rotation does NOT remodel and causes permanent functional deficit.

Final Position for Casting Position: hip flexed 30-40° (comfortable, stable for fracture), knee flexed 30-40° (comfortable), neutral rotation (patella forward). Opposite leg: abducted slightly 10-20°, knee extended or flexed 45° for one-and-a-half spica. Confirm position and reduction on fluoroscopy before proceeding with cast application.

Step 5: DDH Position - Human Position

Hip Position for DDH For DDH POST-REDUCTION (after closed or open reduction): HUMAN POSITION critical to minimize AVN risk. (1) Hip flexion 90-110° (not >110° - stretches femoral nerve, causes palsy). (2) Hip abduction 40-50° (CRITICAL: NOT >60° - excessive abduction stretches medial femoral circumflex artery, increases AVN from 5-10% to 15-20%). (3) Internal rotation 10-20° (stable position). (4) Knee flexion 90° or extended depending on surgeon preference.

Confirmation of Reduction and Safety Confirm hip REDUCED on fluoroscopy or clinical exam: stable to gentle adduction (safe zone test), no telescoping with axial load. Palpate femoral pulses bilaterally - loss indicates vascular compromise requiring immediate repositioning. Check femoral nerve function if possible (quadriceps contraction to stimulus).

Safe Zone Testing Ramsey safe zone: gentle adduction should NOT cause re-dislocation. Excessive abduction beyond safe zone increases AVN without improving stability. Modern protocols aim for minimal safe abduction.

Step 6: Stockinette and Padding Application

Stockinette Layer Apply STOCKINETTE as smooth inner layer: Start at nipple line, extend over trunk and down both legs to toes (or to knees for one-and-a-half spica). Cut generous hole for perineum and genitalia - opening should be larger than expected (will trim later for exact fit). Smooth out all wrinkles carefully - wrinkles create pressure points and skin breakdown.

Padding Layer Apply PADDING (cast padding or ortho-wool) over stockinette: (1) 2-3 layers circumferentially over ALL bony prominences: ASIS bilaterally, iliac crests, sacrum, greater trochanters, tibial crests. (2) Wrap circumferentially around trunk and limbs with 50% overlap, smooth and even. (3) Extra padding at groin creases, under knees in popliteal fossa, around perineum. (4) Total thickness: thin enough for adequate immobilization, thick enough for skin protection.

Waterproof Barrier Apply WATERPROOF barrier at perineum: plastic sheeting, Gore-Tex liner, or waterproof tape creating barrier between skin and cast. This is essential - soiling from urine and stool inevitable, waterproofing prevents cast breakdown and skin maceration. Extend barrier 2-3cm beyond perineal opening onto padding.

Step 7: Body Jacket Application - First Layer

Trunk Component Begin with 4-6 layers of fibreglass or plaster around TRUNK. Start at nipple line anteriorly (allows chest expansion for breathing), extend to just above iliac crests posteriorly and to pubic symphysis anteriorly. Apply circumferentially but NOT tight - allow for abdominal expansion, breathing, feeding.

Molding and Shaping MOLD gently around abdomen and back with palms (not fingers - prevents indentations). Ensure perineal opening adequate: should accommodate two fingers width for expansion, access for hygiene, and diaper changes. Trim excess material around perineal opening with cast scissors while still wet.

Avoid Over-Tightening DO NOT make circumferential compression too tight. Children breathe abdominally, need room for chest and abdominal expansion. Tight anterior compression risks superior mesenteric artery syndrome (SMA syndrome) from duodenal compression between SMA and aorta - presents as vomiting, feeding intolerance.

Step 8: Affected Leg Application - Femur Fracture

Leg Component for Fracture For ONE-AND-A-HALF SPICA (femur fracture): Apply fibreglass or plaster to affected leg from groin to toes, incorporating into body jacket at groin. Maintain reduction with gentle traction and molding during application - assistant holds position while surgeon applies cast. 4-6 layers circumferentially.

Molding at Fracture Site Three-point molding at fracture site: apply pressure opposite the apex of angulation. If apex anterior angulation, apply pressure anteriorly above and below fracture, posteriorly at fracture. Gentle molding only - excessive pressure causes skin injury.

Distal Extent Extend to toes but leave toes exposed (metatarsal heads visible) for neurovascular monitoring. At knee: avoid hyperflexion, maintain 30-40° flexion, keep popliteal fossa accessible. Check reduction on fluoroscopy during and after leg component application.

Step 9: Unaffected Leg Application - One-and-a-Half Spica

Opposite Leg for Rotational Control For ONE-AND-A-HALF: Apply cast to unaffected leg from groin to ABOVE KNEE only (stops 2-3 finger widths above superior pole of patella). This provides rotational control for femur fracture while allowing knee flexion for sitting, mobility, and easier toileting. 4-6 layers circumferentially.

Connection to Body Jacket Connect unaffected leg component firmly to body jacket at groin. Apply extra layers at junction for reinforcement. This junction is high-stress area and breaks without reinforcement.

Bilateral Spica Variation For BILATERAL spica (DDH or post-operative): both legs included to above knees or to ankles depending on protocol and surgeon preference. Maintain human position for DDH: both hips in 40-50° abduction, 90-110° flexion.

Step 10: Cross-Bar and Reinforcement

Cross-Bar (Spreader Bar) Creation Create CROSS-BAR between thighs for structural rigidity: use additional plaster or fibreglass rolls to connect medial aspects of both leg components. Apply 3-4 layers creating solid bar. This prevents scissoring, maintains leg position, and provides handle for safe turning and positioning of child.

High-Stress Area Reinforcement REINFORCE critical junctions with 2-3 extra layers: (1) Body jacket to leg junction at groin bilaterally (highest stress area, most common breakage site). (2) Cross-bar connections to legs. (3) Posterior trunk from sacrum to mid-back (prevents breaking when child sits). Apply extra layers circumferentially at these areas.

Width of Cross-Bar Cross-bar width: adequate for rigidity and handle but NOT too wide - excessive width prevents adequate perineal access for diaper changes and hygiene. Typically 8-12cm between medial thigh components.

Step 11: Molding and Shaping While Setting

Active Molding During Setting While cast is setting (still pliable, first 5-10 minutes): MOLD key areas with palms not fingers. (1) LATERAL thigh at fracture site: three-point fixation as described above. (2) Abdomen gently for comfort (NOT too tight - allow expansion). (3) Gluteal area to prevent posterior sag and improve contour. (4) Smooth all edges especially perineum, groin, trunk edges.

Support During Setting Support cast on pillows during setting phase - do NOT place child on flat surface which flattens posterior aspect. Use pillows under back, thighs, calves to maintain contour. Flat posterior surface creates discomfort and increases sacral pressure sore risk.

Avoid Indentations Use palms for broad pressure distribution, NOT fingers which create indentations. Finger indentations become pressure points causing pain and potential skin breakdown.

Step 12: Edge Finishing and Perineal Protection

Edge Trimming Once cast semi-set (still slightly pliable, 10-15 minutes): trim and smooth all edges with cast scissors. (1) Perineal opening: trim to adequate size (two fingers width), smooth edges, remove any sharp points. (2) Upper trunk: trim to comfortable level allowing arm movement and breathing. (3) Leg distally: trim around toes leaving metatarsal heads visible, smooth edges. (4) Unaffected leg: trim at appropriate level above knee, smooth.

Petaling Edges Apply PETALING to all edges using waterproof tape or moleskin: fold over cast edge creating smooth finished edge. This prevents skin irritation from sharp cast edges and provides finished appearance.

Waterproof Sealing of Perineum Apply WATERPROOF tape circumferentially around entire perineal opening extending 2-3cm onto cast surface. This creates waterproof seal preventing urine and stool infiltration which dissolves plaster and causes skin maceration. Some surgeons use Gore-Tex or similar waterproof liner for superior protection.

Step 13: Immediate Post-Application Assessment

Neurovascular Examination BEFORE patient wakes from anaesthesia perform thorough assessment: (1) Check CIRCULATION: capillary refill in all toes bilaterally, compare to pre-cast baseline, should be less than 2 seconds. (2) Palpate dorsalis pedis and posterior tibial pulses if possible through cast or at exposed areas. (3) Check cast not excessively tight: attempt to slide finger under cast edges at groin and trunk, should have small amount of space. (4) Document neurovascular exam in notes.

Radiographic Confirmation Final x-rays (AP and lateral) to confirm fracture alignment maintained through casting process. For DDH, confirm hip remains reduced and in appropriate position. Compare to pre-casting films.

Perineal Access Check Confirm perineal opening adequate for hygiene and diaper changes: two fingers should fit comfortably. If inadequate, trim further while cast still slightly pliable.

Step 14: Post-Spica Care Instructions and Discharge Planning

Family Education - Skin Care Comprehensive FAMILY EDUCATION before discharge: (1) SKIN CHECKS: inspect skin at all cast edges twice daily, look for redness, breakdown, odor, swelling. Use flashlight to look inside cast edges. (2) Position changes every 2-3 hours: rotate between supine, right side, left side, semi-reclined. NEVER leave prone unsupervised (suffocation risk in young infants). Use pillows for support in each position.

Neurovascular Monitoring (3) NEUROVASCULAR checks: examine toes twice daily for color (pink), warmth (compare to hands), capillary refill (less than 2 seconds), movement (wiggle toes). Red flags: blue/purple discoloration, cold toes, no capillary refill, severe pain - these require immediate emergency department presentation.

Hygiene Management (4) HYGIENE: waterproof diaper positioning under cast opening, tuck plastic wrap under cast edges during all bowel movements to prevent infiltration. Clean perineal area gently with mild soap and water, dry thoroughly. Change diapers frequently to minimize soiling exposure.

Transportation and Positioning (5) TRANSPORTATION: specialized car seat required for spica (E-Z-On vest, Britax Hippo, or custom car bed for bilateral spica). Standard car seats cannot accommodate spica safely or legally. (6) FEEDING: position upright or 45° reclined for feeding, smaller frequent meals if early satiety from abdominal compression. Burp frequently.

Warning Signs (7) WARNING SIGNS requiring urgent medical attention: foul odor from cast (suggests skin breakdown or infection), fever >38.5°C (infection), excessive pain not controlled with simple analgesia, toe discoloration blue/purple/white (vascular compromise), cast loose or cracked (loss of immobilization), persistent vomiting or inability to feed (SMA syndrome), swelling at cast edges (too tight).

Follow-Up Schedule Follow-up appointments: 1 week (mandatory skin check, x-ray confirm alignment maintained), then every 2-3 weeks until removal. Total duration: 6-12 weeks for femur fracture (younger children heal faster), 12 weeks standard for DDH.

Step 15: Spica Removal

Timing of Removal After 6-12 weeks for fracture (confirm healing on x-ray: bridging callus on 3 of 4 cortices), 12 weeks for DDH (acetabular remodeling requires time). X-rays mandatory before removal to confirm: fracture union or DDH hip position maintained and stable.

Removal Technique Spica removal: typically in clinic for cooperative children, OR with sedation for anxious or young children. Use oscillating cast saw with blade guard. Make multiple parallel cuts on LATERAL aspects of cast (avoid anterior cuts which risk abdominal injury). Cut through padding layer, then spread cast with spreaders. Remove in pieces: body jacket first, then legs.

Post-Removal Skin Care Skin will be dry, scaly with accumulated dead skin - reassure family this is NORMAL and expected. GENTLE washing with mild soap and water, pat dry, apply moisturizer. Avoid aggressive scrubbing which causes further irritation. Dead skin will slough over several days with normal bathing.

Rehabilitation Muscle atrophy universal after spica immobilization especially bilateral or prolonged casting. Hip and knee stiffness common, usually resolves in 2-4 weeks with normal activity. Formal physical therapy rarely needed in young children who spontaneously regain motion and strength. Encourage normal play, stairs, outdoor activity. Antalgic gait common for 1-2 weeks post-removal, resolves spontaneously.

Additional Complications

Infection and Skin Infection (2-5%) From soiling, pressure sores, or wound if post-operative. Recognition: fever, foul odor, purulent drainage visible at cast edges. Prevention: meticulous hygiene, waterproofing, antibiotics for post-operative cases per protocol. Management: cast removal, wound cultures, antibiotics based on organisms (typically Staphylococcus aureus, Streptococcus), local wound care.

Respiratory Compromise (Rare <1%) Tight cast restricts breathing especially in infants or underlying lung disease. Recognition: tachypnea, desaturation, increased work of breathing, distress. Prevention: body jacket starts at nipple line, avoid tight circumferential, monitor respiratory status post-application. Management: cast removal immediately if respiratory distress, supportive care, consider surgical fixation.

Psychosocial Issues (Common but Under-Recognized) Prolonged immobilization in young children causes distress. Family stress from care demands. Siblings may feel neglected. Recognition: child regression behaviours, sleep disturbance, family stress visible. Prevention: pre-operative counseling, realistic expectations, social work support. Management: reassurance, child life specialist input, consider early cast removal if healing adequate.

Femoral Nerve Palsy (Rare <1%) From excessive hip flexion >110-120° stretching femoral nerve. Recognition: loss of quadriceps function, decreased sensation anterior thigh, inability to extend knee. Prevention: maintain hip flexion 90-110° maximum. Management: usually temporary, cast removal and repositioning with less hip flexion, most recover fully over weeks to months.

Cast Saw Injuries (1-2%) Skin burns or lacerations during removal if poor technique. Prevention: always use blade guard, multiple short cuts avoiding prolonged contact, lateral cuts only avoiding abdomen. Management: minor burns - local wound care, observation. Lacerations - may require suturing, tetanus prophylaxis.

Immediate Post-Application (0-24 Hours) Hospital observation 4-24 hours post-application depending on patient stability and family capability. Monitor: comfort level, feeding tolerance, neurovascular status (capillary refill, toe color, temperature), respiratory status (work of breathing, saturations), cast integrity. Analgesia: paracetamol regular dosing, ibuprofen if needed. Assess family capability for home care before discharge.

Discharge Criteria Child comfortable with pain controlled on oral analgesia. Feeding well, tolerating normal diet. Neurovascular examination normal (capillary refill <2 seconds, warm pink toes bilaterally). Family demonstrates competency: positioning techniques, skin checks, hygiene management, recognizes warning signs. Specialized car seat arranged for safe transportation home.

Home Care Instructions (Written and Verbal) Position changes every 2-3 hours: rotate supine, right side, left side, semi-reclined. Use pillows for support. NEVER prone unsupervised (suffocation risk). Skin checks twice daily: inspect edges with flashlight, check for redness, breakdown, odor. Neurovascular checks twice daily: toe color, warmth, capillary refill, movement. Hygiene: waterproof with plastic wrap for all diaper changes, clean perineal area gently, dry thoroughly, frequent diaper changes. Feeding: upright or 45° reclined, smaller frequent meals if early satiety. Activity: floor play encouraged, never prone unsupervised.

Follow-Up Schedule 1 week (mandatory): wound check if post-operative, skin examination all cast edges, x-ray confirm alignment maintained, assess family coping and care techniques. 2-3 weeks: x-ray, clinical assessment, address any issues (soiling, skin concerns, cast loosening). Every 2-3 weeks thereafter until removal: x-ray to monitor healing, assess cast integrity.

Duration of Immobilization Femur fracture: 6-12 weeks age-dependent (younger children heal faster). Age <2 years: typically 6 weeks. Age 2-3 years: 6-8 weeks. Age 3-5 years: 8-12 weeks. Confirm healing: bridging callus visible on 3 of 4 cortices on x-ray. DDH: 12 weeks standard (some protocols 6 weeks then abduction brace). Post-operative: variable per surgeon preference and procedure, typically 6-12 weeks.

Cast Removal When fracture healed (bridging callus 3 cortices on x-ray) or DDH timeframe complete. Removal in clinic if cooperative, OR with sedation if anxious. Post-removal expectations: muscle atrophy universal, hip and knee stiffness common, resolves with normal activity over 2-4 weeks. Formal physiotherapy rarely needed in young children - encourage normal play and activity. Antalgic gait 1-2 weeks normal, resolves spontaneously.

References

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