30th April 2024

A 45-year-old man, who is a diabetic, presents with a 3-week history of increasing pain in his right foot.

A 45-year-old man, who is a diabetic, presents with a 3-week history of increasing pain in his right foot. He reports a minor injury to his foot 1 month ago. On examination, there is redness, swelling, and warmth over the right midfoot, and he is unable to bear weight due to pain. His temperature is 38.3°C.

Investigations:

Haemoglobin: 135 g/L (130–175)

White cell count: 15.2 × 10⁹/L (4.0–11.0)

CRP: 95 mg/L (<5)

ESR: 45 mm/h (<20)

Serum glucose: 9.8 mmol/L (3.9–6.1)

Which is the most appropriate investigation to gain a diagnosis?