Non-thumb metacarpal fracture (neck)

Background

Clinical Features

  • 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

Differential Diagnosis

Hand and Finger Fracture Types

Examination

  • Hand xrays

Hand Examination

  • Assess angulation[1]
    • 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

Management

General Fracture Management

Acute Reduction

  • Acute reduction indicated:
    • Pseudo-clawing
    • Significant angulation (>10-15 degrees of the 2nd through 4th fingers, 20-30 degrees of the 5th) [2]
    • Any rotational misalignment
  • Reduction technique:
    • Pain control and/or Hematoma block
    • Flex MCP joint to 90 degrees then apply axial traction while placing pressure over metacarpal shaft
    • Radial gutter splint if 2nd/3rd MCP fractures, Ulnar gutter splint if 4th/5th. Immobilize with wrist extended 20-30 degrees and MCP flexed 90 degrees
    • Can be difficult to reduce or maintain reduction. Early hand referral if not successful

Metacarpal Fracture (Post-Reduction) Goals

Finger Shaft Angulation (degrees) Shaft Shortening (mm) Neck Angulation (degrees) Rotational Deformity
Index & Long Finger 10-20 2-5 10-15 None
Ring Finger 30 2-5 30-40 None
Little Finger 40 2-5 50-60 None

Immobilization

Disposition

  • Outpatient

Refer for

  • Comminution
  • Rotational malalignment
  • Unsuccessful reduction if required[1]

See Also

References

  1. 1.0 1.1 German C. Hand and wrist emergencies. In: Bond M, ed. Orthopedic Emergencies: Expert Management for the Emergency Physician. Cambridge: Cambridge University Press; October 31, 2013.
  2. Davenport M. Procedures for orthopedic emergencies. In: Bond M, ed. Orthopedic Emergencies: Expert Management for the Emergency Physician. Cambridge: Cambridge University Press; October 31, 2013.
  3. Hofmeister, EP. Comparison of 2 methods of immobilization of fifth metacarpal neck fractures: a prospective randomized study. The Journal of Hand Surgery. 2008; 33(8):1362-1368.