Non-thumb metacarpal fracture

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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

Differential Diagnosis

Hand and Finger Fracture Types

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[1]

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

Non-thumb metacarpal fracture (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

Differential Diagnosis

Hand and Finger Fracture Types

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[2]
  • Acute reduction indicated:
    • Pseudoclawing
    • Significantly angulated 4th or 5th MC fx

Dispo

  • Refer for:
    • Comminution
    • Rotational malalignment

Non-thumb metacarpal fracture (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)

Differential Diagnosis

Hand and Finger Fracture Types

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

Non-thumb metacarpal fracture (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

Differential Diagnosis

Hand and Finger Fracture Types

Treatment

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

Source

  1. http://dx.doi.org/10.1016/j.jhsa.2008.04.010.
  2. 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.