Metacarpophalangeal dislocation (finger)

Background

• Also known as the MCP joint
• Usually forces that rupture volar plate cause dorsal dislocation

Clinical Features

• Mechanism: hyperextension
• Finger pain/deformity

Differential Diagnosis

Hand and finger dislocations

• Finger dislocations
  • Distal interphalangeal dislocation (finger) (DIP)
  • Proximal interphalangeal dislocation (finger) (PIP)
  • Metacarpophalangeal dislocation (finger) (MCP)
• Thumb dislocations
  • Interphalangeal dislocation (thumb) (IP)
  • Metacarpophalangeal dislocation (thumb) (MCP)
• Hand dislocations
  • Carpometacarpal dislocation

Evaluation

Types

• Simple: subluxation
  • Joint appears hyperextended to 60-90 deg
• Complex: dislocation
  • MCP joint is in moderate hyperextension with metacarpal head prominent in palm
  • Volar plate is interposed in MCP joint space
  • X-ray may show seasamoid within joint space (pathognomonic)
    • Closed reduction is not possible

Management

Reduction

• Do NOT hyperextend joint (may convert subluxation into complete dislocation)
• Flex the wrist to relax the flexor tendon
• Apply pressure over dorsum of proximal phalanx in distal and volar direction

Splinting

• Splint with MCP joint in flexion
• Refer to hand surgeon

Disposition

• Outpatient management

See Also

• Hand and finger dislocations