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

Hand and finger injuries

• Radiograph positive
  • Hand and finger fractures
  • Hand and finger dislocations
  • Triquetrolunate ligament instability
• Radiograph negative
  • Dupeytren contracture
  • Boutonniere deformity
  • Hand and finger tendon injuries
  • Ganglion cyst
  • De Quervain tenosynovitis
  • Intersection syndrome
  • Drummer's wrist
  • Extensor digitorum tenosynovitis
  • Vaughn Jackson syndrome
  • Snapping Extensor Carpi Ulnaris
  • Compressive neuropathy, "bracelet syndrome"
  • Scaphoid fracture
  • Osteoarthritis
  • Infiltrative tenosynovitis
  • Gout
  • Rheumatoid arthritis
  • Trigger finger
  • Mallet finger
    • Swan neck deformity
  • Jersey finger
  • Jammed finger
  • Subungual hematoma
  • Fingertip laceration
  • Metacarpophalangeal (MCP) ulnar ligament rupture (Gamekeeper's thumb)
  • Nail avulsion
  • High-pressure injection injury

Evaluation

MCP dislocation of thumb

• 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

Disposition

• Outpatient

See Also

• Hand and finger dislocations

References

Authors

Ross Donaldson, Daniel Ostermayer, Neil Young