Atlantoaxial Traumatic Ligament Disruption

  • If there is an ADI of >4.5 mm this implies ligamentous compromise
  • Isolated transverse atlantoaxial ligament instability is rare in normal children
  • However, it may occur frequently in Down’s syndrome, RA, Larsen syndrome, & bony dysplasia including mucopolysaccharidosis & various dwarfism
  • Bony abnormality including Klippel Feil syndrome may be associated with instability
  • Goldenhar & Apert syndrome may be associated with instability
Atlantoaxial Traumatic Ligament Disruption, ct of a hangman fracture
CT of a hangman fracture. Image by Michael Utz, Shadab Khan, Daniel O’Connor & Stephen Meyers, Wikimedia Commons, CC BY 4.0.

History

  • Above patients may be predisposed
  • Cranial nerve, long tract signs & sphincter dysfunction, gait abnormality

Treatment

  • acute injury should be immobilised in extension, followed by posterior fusion of C1 to C2 using a Halo postoperatively
  • Chronic situation including Down’s wait up to 10 mm of displacement or SAC < 13 mm stabilisation is indicated
  • If there is a < 10 mm ADI but the physical or history is suggestive of embarrassment then fuse
  • Fusion is typically sublaminar BUT no sublaminar wires if the patient does not reduce
  • If the Down’s ADI is greater than 4.5 mm should restrict the child from contact sport/trauma

Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.