Non-thumb metacarpal fracture (base)

Background

• Reverse Bennett: fracture of fifth metacarpal base, with extensor carpi ulnaris traction on distal metacarpal while proximal fragment still algined with carpals
  • See Thumb fracture for Bennett fracture

Clinical Features

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

Differential Diagnosis

Hand and Finger Fractures

• Non-thumb metacarpal fractures
  • Head
  • Neck
  • Shaft
  • Base
  • Boxer's fracture
• Thumb fracture
• Finger (Phalanx) Fracture
  • Proximal
  • Middle
  • Distal

Evaluation

• Xray hand: 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 fracture despite "negative" plain films

Management

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

Disposition

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

See Also

• Hand and finger fractures

References

Authors

Ross Donaldson, Ted Fan, Neil Young, Daniel Ostermayer