What is the treatment for a boxer's fracture using an ulnar gutter cast?

Treatment of Boxer's Fracture with Ulnar Gutter Cast

For boxer's fractures (fifth metacarpal neck fractures) with angulation up to 70 degrees and no rotation, immediate mobilization with a pressure bandage is superior to traditional ulnar gutter cast immobilization, resulting in equivalent functional outcomes with faster return to activity. 1

Initial Assessment

When evaluating a boxer's fracture, measure the following specific parameters:

• Angulation tolerance: Up to 70 degrees of volar angulation is acceptable without reduction 1
• Rotation: Any rotational deformity is unacceptable and requires correction 1
• Displacement: Document degree of displacement on true lateral radiographs 1

Treatment Algorithm

For Fractures ≤70 Degrees Angulation Without Rotation:

Preferred approach:

• Apply pressure bandage for 1 week 1
• Begin immediate mobilization within pain limits 1
• No formal immobilization required 1

Alternative approach (if ulnar gutter splint preferred):

• Apply ulnar gutter splint immobilizing fourth and fifth metacarpals 2
• Remove at 3 weeks maximum 1
• Begin mobilization exercises 1

For Fractures >70 Degrees or With Rotation:

• Closed reduction is indicated 1
• Post-reduction immobilization with ulnar gutter splint 2

Evidence Supporting Early Mobilization

A prospective randomized trial directly compared 3-week ulnar gutter cast immobilization versus pressure bandage with immediate mobilization in 35 patients with boxer's fractures (mean angulation 39 degrees, range 15-70 degrees). 1 The study found:

• No statistical differences in range of motion of the fifth MCP joint between groups 1
• No differences in patient satisfaction, pain perception, return to work/hobby, or need for physiotherapy 1
• Equivalent outcomes regardless of treatment method 1

This high-quality evidence demonstrates that traditional 3-week immobilization provides no functional benefit over immediate mobilization for acceptable angulations. 1

Critical Pitfalls to Avoid

• Do not immobilize beyond 3 weeks: Extended immobilization increases stiffness risk without improving outcomes 1
• Do not reduce fractures <70 degrees angulation: Reduction provides no value for ROM of the fifth MCP joint 1
• Never accept rotational deformity: Even minimal rotation is functionally unacceptable 1
• Ensure finger motion: Active finger exercises should begin immediately to prevent stiffness 3

Follow-Up Protocol

• Evaluate at 1 week for pain tolerance and compliance 1
• Reassess at 6 weeks for clinical union 1
• Final evaluation at 12 weeks for ROM and functional outcome 1
• Obtain radiographs at 3 weeks and at cessation of immobilization 3

When Ulnar Gutter Splint Is Indicated

Despite evidence favoring early mobilization, ulnar gutter splinting remains appropriate for:

• Patient preference for immobilization 2
• Concerns about compliance with activity modification 2
• Occupational requirements necessitating protection 2
• Post-reduction stabilization for fractures >70 degrees 1, 2

If using an ulnar gutter splint, limit duration to 3 weeks maximum and ensure it does not obstruct full finger range of motion. 1, 4