Perilunate and lunate dislocations

From WikEM
Jump to: navigation, search

Background

  • Occur via high-energy FOOSH injury (fall from height, MVC)
    • Perilunate Dislocation = Lunate stays in place, capitate is displaced
    • Lunate Dislocation = Capitate stays in place, lunate is displaced
  • Must rule-out median nerve injury
  • Must rule out carpal bone fractures

Clinical Features

  • Perilunate dislocation: dorsal swelling with palpable mass
  • Lunate dislocation: volar swelling with palpable mass

Diagnosis

Perilunate Dislocation
Lunate Dislocation

Perilunate Dislocation

  • Lateral view
    • Capitate displaced dorsal to lunate
    • Lunate retains its normal contact w/ radius
  • PA view
    • Capitolunate joint space is obliterated as the bones overlap one another

Lunate Dislocation

  • Lateral view
    • Lunate is pushed off the radius into the palm ("spilled teacup" sign)
  • PA view
    • Lunate has triangular shape ("piece-of-pie sign")

Differential Diagnosis

Carpal Dislocations

Carpal fractures

Treatment

  • Closed reduction and long-arm splint
    • Likely requires emergent ortho consultation (very difficult to reduce)

See Also

Source

  • Emergency Orthopedics, The Extremeties
  • Radiopaedia.org
  • Tintinalli