Question
An 84 year old woman falls from standing and has neck pain. She is neurologically intact.
- How is this injury classified?
- What are the management options?
- What factors affect union?
Answer
Anderson and D’Alonzo classification
| Type | Description |
|---|---|
| I | Tip avulsion above the transverse ligament, stable |
| II | Fracture at the base of the dens, highest nonunion rate |
| III | Extends into the C2 body, unites well |
Management
- Hard collar for type I, type III and frail patients with type II
- Halo vest is poorly tolerated in the elderly, with pneumonia and death
- Posterior C1 to C2 fusion for unstable or displaced type II
- Anterior odontoid screw for type II with a favourable fracture line, good bone and an intact transverse ligament
- A stable fibrous union is an acceptable outcome in the very elderly
Factors for nonunion
- Displacement over 5 mm
- Posterior displacement
- Angulation over 10 degrees
- Increasing age and smoking
Related pages
Author Contributions
Orthofracs team
Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.