What is the technique for applying a plaster cast to a reduced elbow fracture?

Plaster Application Technique for Elbow Fractures

For pediatric supracondylar elbow fractures, the preferred treatment is closed reduction with percutaneous pin fixation rather than plaster immobilization alone, as plaster casting of displaced fractures carries significant risks including limb-threatening ischemia from hyperflexion positioning 1.

Treatment Algorithm Based on Fracture Type

Displaced Supracondylar Fractures (Gartland II/III)

• Closed reduction with pin fixation is recommended over plaster casting alone 1
• Plaster immobilization in hyperflexion poses risk of vascular compromise and should be avoided 1
• After pin fixation, immobilization is used as adjunct protection, not primary treatment

If Plaster Technique is Used (Non-displaced or Post-pinning Immobilization)

Extension Position Technique (for extension-type fractures):

• Apply U-shaped plaster slab with elbow in full extension 2
• This neutralizes both extensor and flexor muscles during reduction
• Allows easy assessment of carrying angle to prevent cubitus varus
• This technique showed 0% cubitus varus rate versus 60.9% with conventional flexion method 2
• Mean HSS elbow score: 91 points (extension) vs 78 points (flexion method) 2

Key Technical Steps:

1. Perform closed reduction with longitudinal traction of forearm, followed by flexion 3
2. Apply U-shaped plaster slab extending from upper arm to wrist
3. Position elbow in full extension (for extension-type fractures) 2
4. Ensure proper molding to maintain reduction 4
5. Include wrist in immobilization for stability 5

Critical Safety Considerations

Vascular Monitoring:

• Any elbow immobilization requires vigilant neurovascular monitoring
• Emergent closed reduction is indicated for decreased hand perfusion 1
• If absent pulses and cold, pale hand persist after reduction and pinning, open exploration of antecubital fossa is required 1

Immobilization Duration:

• Elbows without redislocation tendency: maximum 1 week 3
• Elbows with redislocation tendency: 2-3 weeks 3
• Prepubertal children: 4 weeks for fracture healing 4
• Pubertal children: 5 weeks 4

Common Pitfalls to Avoid

1. Never immobilize displaced supracondylar fractures in hyperflexion - this can cause limb-threatening ischemia 1
2. Do not rely on plaster alone for displaced fractures - pin fixation is superior (NNT=20 for preventing cubitus varus, NNT=7 for Flynn's criteria) 1
3. Monitor cast index - this is a measurable parameter for proper cast application 4
4. Take any complaint of increased pain seriously - investigate immediately for compartment syndrome or pressure issues 6

Follow-up Protocol

• Week 1: Clinical-radiological control for repositioned fractures (consider cast wedging if needed) 4
• Monitor for loss of reduction, especially with conventional flexion methods (occurred in 7/46 patients requiring re-manipulation) 2
• Assess for early complications: infection, neurovascular compromise, stiffness 1

The evidence strongly favors the extension position technique when plaster is used, though surgical fixation remains the gold standard for displaced fractures to optimize morbidity and functional outcomes 1, 2.