What is the preferred initial splint for a comminuted fracture of the fourth metacarpal?

Splinting for Fourth Metacarpal Comminuted Fracture

For a comminuted fracture of the fourth metacarpal, use a hand-based functional splint that immobilizes the fracture site while allowing immediate metacarpophalangeal (MCP), interphalangeal (IP), and radiocarpal joint motion. 1, 2

Splint Selection and Design

• A hand-based functional splint is the preferred initial immobilization method for non-operative fourth metacarpal fractures, including comminuted patterns that meet conservative treatment criteria 2
• The splint must be removable to permit radiographic assessment, dressing changes, and functional exercises 3
• The design should specifically allow MCP joint, IP joint, and wrist motion throughout the treatment period to prevent the most functionally disabling complication: joint stiffness 1, 2

Critical Pre-Splinting Assessment

Before applying any splint, obtain standard 3-view radiographs (posteroanterior, lateral, and oblique) to confirm alignment and rule out surgical indications 1, 4

Absolute Contraindications to Splinting (Require Surgery Instead):

• Displacement >3 mm 1, 4, 3
• Dorsal tilt >10° 1, 4
• Significant intra-articular involvement or step-off 1, 4
• Rotational malalignment 5
• Shortening >5 mm 5

If any of these criteria are present, refer for surgical fixation rather than proceeding with splinting alone. 1, 4

Splint Duration and Follow-Up Protocol

• Average splint duration is 24 days (range 3-4 weeks) 1, 2
• Mandatory radiographic follow-up at 3 weeks is essential to detect delayed displacement that would require conversion to surgery 1, 4, 3
• Obtain additional radiographs at splint removal (3-4 weeks) to confirm adequate healing 1, 3

Common Pitfall to Avoid:

Failure to obtain the 3-week follow-up radiographs is the most critical error, as it can miss delayed displacement requiring surgical intervention 3

Immediate Rehabilitation Protocol

• Begin active finger motion exercises immediately following splint application for all non-immobilized joints 1, 4, 3
• Active finger motion does not adversely affect adequately stabilized metacarpal fractures and is safe when the fracture meets conservative treatment criteria 1, 4
• Early motion is essential because joint stiffness is one of the most functionally disabling complications of metacarpal fractures 1
• This approach allows immediate return to pre-injury activities in most patients, with 20 of 24 employed patients able to continue working without missing any days 2

Expected Complications

• Immobilization-related complications occur in approximately 14.7% of cases, most commonly skin irritation and muscle atrophy 1, 3
• These complications are minimized by using a functional splint that permits motion rather than rigid immobilization 2

Alternative Consideration for Specific Fracture Patterns

For subcapital (neck) fractures of the fourth metacarpal specifically, some evidence supports treatment with immediate mobilization without any splinting or reduction, showing 92% healing rates and 86% patient satisfaction 6. However, this approach is less applicable to comminuted shaft fractures where some stabilization is typically warranted 2.