Lunate Dislocation

Pathology

  • Mechanism is often a FOOSH
  • The lunate is dislocated from the radiocarpal joint

Assessment Findings

  • Swelling
  • Pain
  • Deformity (often a lump in the dorsum of the carpus)
  • Pit located where lunate should be
  • Reduced range of motion
  • Potentially symptoms of median nerve compression (which warrant rapid surgical intervention)
    • Altered sensation in the radial 3 1/2 fingers
    • Reduced power of the thumb flexors / opposers
  • X-ray
    • On the AP x-ray:
      • The lunate is not located where is should be, adjacent to the scaphoid and capitate.
      • The intercarpal distances will be uneven
      • Lunate will appear to overlap all adjacent bones

    • On the the lateral x-ray:
      • The lunate is not seated within the radial fossa and distally, the capitate is not located within the lunate fossa.
      • The radius, lunate and capitate can normally be linked by an imaginary vertical line – with a dislocated lunate, this is lost.
      • The lunate loses its normal orientation, where it is parallel to the tilt of the radius

 

 

Management

  • The management for a lunate dislocation is surgery