A 24-year-old man sustains a displaced talar neck fracture treated with closed reduction and casting. At 8 weeks post-injury, radiographs show subchondral lucency in the dome of the talus. This finding indicates:

• A Progressive avascular necrosis requiring arthrodesis
• B Early post-traumatic arthritis of the subtalar joint
• C An intact blood supply to the talar body and a favourable prognosis ✓
• D Infection of the talar body

Explanation

Subchondral atrophy producing a lucent band under the talar dome at 6 to 8 weeks is the Hawkins sign. It can only develop if the blood supply to the talar body is intact, so it reliably predicts absence of avascular necrosis. Its absence does not confirm AVN because it may be masked by immobilisation. Lucency is resorption from revascularisation, not infection or arthritis.

Reference: Campbell's Operative Orthopaedics, 14th ed.

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