Question
A 25 year old woman is injured in a car crash, with forced dorsiflexion of her foot. Radiographs show a displaced talar neck fracture with subluxation of the subtalar joint.
- How are these fractures classified and what is the prognosis?
- Why is the talus at risk of avascular necrosis?
- Outline your management.
Answer
Classification (Hawkins, with Canale and Kelly)
| Type | Description | AVN risk |
|---|---|---|
| I | Undisplaced | Up to about 10% |
| II | Subtalar subluxation or dislocation | About 40% |
| III | Subtalar and ankle dislocation | Up to 90% |
| IV | Type III with talonavicular dislocation | Very high |
Blood supply
- About 60% of the talus is covered by cartilage, so vessels enter only at limited sites
- Artery of the tarsal canal from the posterior tibial artery supplies most of the body
- Dorsalis pedis and the artery of the tarsal sinus from the peroneal artery also contribute
- Displacement disrupts these vessels
Management
- Urgent closed reduction of dislocations to relieve skin pressure
- ORIF through combined anteromedial and anterolateral approaches to avoid varus malreduction
- Screws and a lateral plate for comminution
- Non weight bearing for 8 to 12 weeks
- Hawkins sign (subchondral lucency at 6 to 8 weeks) indicates revascularisation
- Complications are AVN, varus malunion and subtalar and ankle arthritis
Related pages
Author Contributions
Orthofracs team
Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.