Wrist

Lunate Dislocation

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Lunate Dislocation, Transnavicular Perilunate Dislocation, Perilunate Dislocation, Isolated Lunate Dislocation, Pure Volar Lunate Dislocation

  • See Also
  1. Scapholunate Dissociation
  • Epidemiology
  1. Most common in children and young adults (with high energy injury)
  • Mechanism
  1. High energy injury (e.g. fall from height, Motor Vehicle Accident)
  • Precautions
  1. Lunate Dislocations are initially missed in up to 25% of cases
  2. Deformities may be subtle
  • Types
  • Lunate Dislocation
  1. Transnavicular Perilunate Dislocation (TransScaphoid Perilunate Dislocation)
    1. Mid-Navicular Fracture
    2. Posterior displacement of distal Navicular Fracture pole and associated Carpal Bones (including Lunate)
    3. May be associated with Median Neuropathy (from Carpal Tunnel compression)
    4. Optimal treatment is with early surgical repair (poor outcome if delayed repair)
  2. Perilunate Dislocation (most common)
    1. Most common carpal dislocation (10% of all carpal dislocations)
    2. Capitate displaces dorsally while the Lunate Bone remains in place, within fossa
    3. Intact navicular bone and wrist dorsally dislocates in relation to Lunate Bone (which remains in fossa)
    4. Missed injury in up to 25% of cases
  3. Isolated Lunate Dislocation (Pure Volar Lunate Dislocation)
    1. Lunate dislocates from Capitate, and displaces into volar (anterior) position
    2. Lunate rotates anteriorly (towards volar wrist)
    3. Associated with significant Ligamentous Injury and complete disruption of radiolunate and intercarpal articulations
    4. Wrist XRay lateral demonstrates anterior Lunate displacement
    5. AP View, Lunate may appear more triangular
  • Symptoms
  1. Pain, swelling, tenderness and decreased range of motion of the affected wrist
  2. Median Nerve Paresthesias may be present
    1. Median Nerve compression is present in 50% of cases
    2. Motor weakness (thumb, index finger, middle finger) may occur in more severe cases
  • Exam
  1. Trauma Exam
    1. High mechanism injury (esp. with Intoxication) is often associated with other injuries
    2. Multiple other injuries in 26% of Lunate Dislocation cases
    3. Ipsilateral upper extremity with additional injuries in 10% of cases
  2. Complete extremity exam (neurovascular, joint above and below, skin and compartments)
    1. Wrist Exam
    2. Hand Neurovascular Exam (esp. Median Nerve)
  3. Careful skin exam overlying dislocation
    1. Open dislocation occurs in 10% of cases
  • XRay
  1. Wrist XRay
    1. Diagnostic in most cases
    2. Isolated Lunate Dislocation
      1. Lunate volar dislocation and rotation ("spilled teacup" appearance) on lateral Wrist XRay
      2. Lunate may appear triangular on AP View
    3. Perilunate Dislocation
      1. Capitate displaced dorsally
      2. Lunate remains in position
  2. CT or MRI
    1. Consider when XRay is non-diagnostic
  • Procedure
  • Closed Reduction of Isolated Lunate Dislocation
  1. Background
    1. All Isolated Lunate Dislocations will ultimately require ORIF (due to carpal instability)
    2. However, attempt closed reduction and Splinting in Emergency Department
  2. Anesthesia
    1. Procedural Sedation or
    2. Median Nerve Block at Wrist (Regional Anesthesia of the Median Nerve)
      1. Short acting agent (e.g. Lidocaine) allows for re-assessment of Median Nerve post-reduction
  3. Technique
    1. Finger traps with 10-15 pound traction for 10-15 minutes
      1. Performed after Median Nerve Block or systemic Analgesics
      2. Maintain inline traction while finger traps are removed
    2. Reduction (under Procedural Sedation or Median Nerve Block)
      1. Patient's wrist positioned in slight flexion
      2. Place one thumb over dorsal Lunate, providing posterior counter support
      3. Place other thumb over the volar Lunate and apply anterior pressure toward dorsal wrist
      4. Closed reduction will fail if interposed joint capsule in dislocation (requires urgent ORIF)
  4. Splinting
    1. Return wrist to slightly flexed or neutral position with slight ulnar deviation
    2. Apply Sugar-Tong Forearm splint
    3. Repeat neurovascular exam after Splinting
  5. Disposition
    1. Obtain post-reduction films
    2. Refer to orthopedics for definitive management (i.e. ORIF, ligamentous repair)
      1. Emergent surgery (typically within 24 hours)
        1. Persistent or recurrent dislocation
        2. Median Neuropathy
      2. Surgery at 3-5 days
        1. Stable closed reduction and Splinting WITHOUT Median Neuropathy
  • Complications
  1. Median Nerve Injury
  2. Lunate Avascular Necrosis (Kienbock Disease)
  3. Open Dislocation
  4. Delayed diagnosis (longterm Disability risk)
  • References
  1. Kiel, Kumetz and Shannon (2019) Crit Dec Emerg Med 33(5): 14-5
  2. Mercier (1995) Practical Orthopedics, Mosby, St. Louis, p. 360-2
  3. Riveros (2025) Crit Dec Emerg Med 39(7): 22-3