What type of splint is recommended for a 5th metacarpal (fifth metacarpal bone) fracture and for how long should it be worn?

Treatment of Fifth Metacarpal Fractures

For fifth metacarpal fractures, use a hand-based functional splint (ulnar gutter splint) that immobilizes the wrist and affected digit while allowing motion of unaffected fingers, worn for 3-4 weeks with radiographic follow-up.

Splint Type Selection

A hand-based functional splint is the optimal choice for fifth metacarpal fractures, providing adequate immobilization while minimizing stiffness and allowing earlier return to function 1, 2. The evidence strongly supports functional splinting over rigid cast immobilization:

• Functional splints allow metacarpophalangeal (MCP) joint, interphalangeal (IP) joint, and radiocarpal joint motion in unaffected digits, which is critical for preventing hand stiffness 1
• Ulnar gutter splints are the traditional approach and remain acceptable, though they restrict more motion than newer hand-based designs 3
• The splint should be padded and comfortably tight but not constrictive, allowing a finger to slip underneath 4

Evidence Supporting Functional Splinting

The research demonstrates clear advantages of functional approaches:

• Functional taping or splinting results in significantly faster functional recovery compared to rigid plaster immobilization, with patients returning to work two-thirds faster 2, 5
• Hand-based functional splints maintain excellent fracture reduction while allowing immediate return to pre-injury activities in most cases 1
• Twenty out of 24 employed patients treated with hand-based splints were able to continue working without missing any days 1

Duration of Immobilization

Immobilize for 3-4 weeks with radiographic follow-up at approximately 3 weeks and at cessation of immobilization 4, 1:

• The average splint duration in recent studies was 24 days (approximately 3.5 weeks) 1
• Obtain radiographic follow-up at 3 weeks to assess healing and alignment 4
• Final radiographic assessment should occur when immobilization is discontinued 4

Critical Management Principles

Immediate Motion Protocol

Begin active finger motion exercises immediately for all unaffected joints to prevent the most functionally disabling complication—finger stiffness 4, 6:

• Active motion does not adversely affect adequately stabilized fractures 4, 7
• Finger stiffness can be extremely difficult to treat after healing, potentially requiring multiple therapy visits and surgical intervention 4, 6
• Transition to aggressive finger and hand motion exercises when immobilization is discontinued 4

Position and Reduction

Splint the fracture in the position found unless straightening is necessary to facilitate safe transport 8:

• Do not attempt to straighten angulated fractures in the first aid setting, as this may cause further injury 6
• Cover any open wounds with a clean dressing to reduce contamination risk 8

Emergency Indications

Activate emergency services immediately if the fractured extremity is blue, purple, or pale, as this indicates poor perfusion and represents a limb-threatening injury 8.

Common Pitfalls to Avoid

• Over-immobilization: Rigid splinting when functional splinting would suffice leads to unnecessary stiffness and prolonged disability 4, 6
• Prolonged immobilization beyond 4 weeks: This increases joint stiffness requiring additional therapy without providing additional benefit 7, 6
• Immobilizing unaffected fingers: This dramatically increases the risk of hand stiffness and functional impairment 4, 1
• Inadequate radiographic follow-up: Failure to obtain 3-week radiographs may miss loss of reduction requiring intervention 4

Comparative Outcomes

While both functional metacarpal splints and traditional ulnar gutter splints yield similar long-term radiological and clinical outcomes at 6 months 3:

• Functional splints provide significantly better grip strength at 2 months (reaching expected values versus persistently lower strength with ulnar gutter splints) 3
• Functional splints show significantly faster improvement in QuickDASH scores between 2 and 6 months 3
• Patient comfort and compliance are better with functional splints due to less joint restriction 3

The evidence clearly favors hand-based functional splinting over rigid immobilization for stable fifth metacarpal fractures, balancing adequate fracture stability with optimal functional recovery 1, 2, 5, 3.