A 24-year-old man sustained a displaced fracture of the talar neck treated with open reduction and internal fixation. At 7 weeks postoperatively, which radiographic finding indicates that avascular necrosis of the talus has NOT occurred?
- A Sclerosis and increased density of the talar body
- B Subchondral radiolucency of the talar dome on the AP view ✓
- C Collapse of the talar dome articular surface
- D Narrowing of the subtalar joint space
Correct answer: B. Subchondral radiolucency of the talar dome on the AP view
Explanation
The Hawkins sign, a subchondral radiolucent band beneath the talar dome seen at 6 to 8 weeks, represents resorption of subchondral bone in a viable, vascularised talus and reliably excludes avascular necrosis. Sclerosis of the body reflects absent remodelling and suggests ischaemia. Dome collapse and joint space narrowing are late changes of established avascular necrosis, not signs of preserved vascularity.
Reference: Rockwood and Green's Fractures in Adults, 9th ed.
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