Should a mallet finger splint be applied in flexion or extension?

Mallet Finger Splinting Position

Mallet finger splints should be applied in extension or slight hyperextension (0-5 degrees) of the distal interphalangeal (DIP) joint, never in flexion. 1, 2

Splinting Position Based on Injury Type

Tendinous (Soft Tissue) Mallet Finger

• Position the DIP joint in slight hyperextension for optimal tendon healing 1
• The slight hyperextension brings the torn tendon ends into closer approximation, facilitating healing 1
• Maintain this position continuously for 6-12 weeks depending on protocol 1, 3

Bony Avulsion Mallet Finger

• Position the DIP joint in neutral (straight/0 degrees extension), not hyperextension 1, 2
• Neutral positioning is preferred for fracture healing to avoid excessive stress on the bony fragment 1
• Duration is typically 6-8 weeks for bony injuries 2

Critical Technical Points

Splint Application Principles

• The splint must immobilize only the DIP joint while allowing full active motion of the PIP joint to prevent stiffness 4
• Dorsal splints are preferred as they preserve digital pulp sensation and function 2
• The splint should be comfortably snug but allow a finger to slip underneath to prevent circulatory compromise 4

Common Pitfalls to Avoid

• Never splint in flexion - this is biomechanically incorrect and will result in treatment failure 1, 2
• Avoid excessive hyperextension (>10 degrees) which can cause skin necrosis or pressure complications 1
• Do not immobilize the PIP joint unless there is instability or subluxation requiring additional stabilization 4

Duration and Monitoring

Immobilization Protocol

• Tendinous injuries: 8-12 weeks full-time splinting followed by 2-4 weeks of night splinting 2, 3
• Bony injuries: 6-8 weeks full-time splinting 2
• Longer immobilization (12 weeks) has shown excellent results with mean extension lag of only 2.6 degrees at final follow-up 3

Patient Monitoring

• Watch for blue or pale discoloration indicating circulatory compromise - this is a medical emergency 4
• Apply cold therapy for 15-20 minutes several times daily during the first week 4
• Ensure patients perform active PIP joint range of motion exercises multiple times daily to prevent stiffness 4

Special Considerations

Unstable Injuries

• For injuries with significant displacement (>3mm), dorsal tilt (>10°), or substantial intraarticular involvement, rigid immobilization is essential 5
• If DIP joint subluxation persists despite splinting, surgical intervention may be required 1, 2

Radiographic Follow-up

• Obtain radiographs at approximately 3 weeks and at time of splint removal to confirm adequate healing 5
• If pain persists or range of motion deteriorates, reevaluate to rule out complications 5