Metacarpophalangeal dislocation (thumb)

Background

• Also known as the MCP joint
• Like other MCP joint dislocations, may be simple or complex

Clinical Features

• Thumb 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

• X-ray thumb (PA and lateral)

Management

• Stable reduction: Immobilize in thumb spica wtih MCP joint in 20 deg flexion for 4wk
• Unstable reduction: ORIF

Reduction

• Radial and median nerve blocks
• Pressure directed distally on base of prox phalanx with metacarpal flexed and abducted

See Also

• Hand and finger dislocations