Non-thumb metacarpal fracture

Head

Background

• Intra-articular Fx

Examination

• Swelling, decreased ROM, and TTP of MCP joint
• Assess for rotational alignment (rotational malalignment is not tolerated)
• Assess for skin integrity (r/o fight bite)

Imaging

• AP, lateral, oblique
  • Angulation assessed on lateral view
• Consider "Brewerton" view if collateral ligament avulsion fx suspected

Treatment

• Ulnar Gutter Splint or Short arm cast that extends to the PIP joint
  • In a comparison of the typical 4th and 5th digit flexed at the MCP joint and a short arm, there was no significant benefit to the intrinsic plus position of the fingers

Dispo

• Almost always refer b/c are intraarticular and typically comminuted
• Non-displaced fx can be splinted for 2-3 weeks followed by ROM exercises

Neck

Examination

• TTP or ecchymosis on the palmar bony surface is highly suggestive of fracture
• Loss of the normal knuckle contour
  • Due to dorsal angulation of fracture apex due to pull of the interosseous muscles
• Assess angulation
  • Head-to-neck angle of the metacarpals is normally 15 degrees
    • Fracture angulation = measured angle minus 15 deg
  • Angle toleration (below which there is no adverse functional outcome)
    • 2nd MC < 10 deg
    • 3rd MC < 20 deg
    • 4th MC < 30 deg
    • 5th MC < 30-40 deg
• Assess rotational alignment by looking for overlap of the 5th over the 4th digit (scissoring or psuedoscissoring)
• Assess extensor apparatus
• Assess skin integrity

Treatment

• Ulnar Gutter Splint or Radial Gutter Splint]
  • MCP joints in 70-90 deg flexion, wrist in 20-30 deg extension, PIP and DIP joints in 5-10 deg of flexion
• Acute reduction indicated:
  • Pseudoclawing
  • Significantly angulated 4th or 5th MC fx

Dispo

• Refer for:
  • Comminution
  • Rotational malalignment

Shaft

Examination

• TTP along affected metacarpal
• Flexion at MCP is difficult
• Assess for extensor dysfunction; pt may exhibit "pseudo-clawing" during attempts at finger extension
• Assess angulation
  • >10 deg in 2nd and 3rd and >20 deg in 4th and 5th metacarpal shaft fractures requires reduction
• Assess rotational alignment

Imaging

• Oblique fx are more prone to shorten and rotate
• Transverse fx generally stable (particularly isolated 3rd or 4th MC shaft fx)

Treatment

• Ulnar Gutter Splint or Radial Gutter Splint]
• Acute reduction indicated if there is pseudo-clawing or significant angulation
  • Closed reduction generally corrects angulation but typically does not restore length

Dispo

• Refer:
  • Malrotation
  • Comminution
  • Shortening > 5mm (refer all shortening if not familiar with fx management)
  • 2 or more metacarpal fractures
  • Unacceptable angulation
  • Long oblique fractures

Base

Examination

• Movement at the wrist elicits pain
• Assess for ulnar deficits (finger abduction/adduction)
• Assess for rotational alignment

Imaging

• AP, lateral, oblique
• 30 deg obliques pronated and supinated if usual films unable to visualize the MC bases
• Consider CT if index of suspicion high for occult fx despite "negative" plain films

Treatment

• Dorsal and Forearm Volar Splint‎ with the wrist in 30 deg of extension and MCP joints free

Dispo

• Refer for:
  • Intraarticular fx
  • Extraarticular fx with malrotation
  • Dislocation of metacarpal base CMC joint;
  • Ulnar nerve injury
  • 5th metacarpal base fx (typically require sx)

See Also

• Hand and finger fractures
• Boxer's fracture

Source

UpToDate