A 72-year-old man presents with an acutely painful left knee. On examination, he has a temperature of 37°C with a hot, swollen right knee. Of relevance amongst his investigations, was his white cell count which was 12.6 × 109/l.

A knee X-ray revealed reduced joint space and calcification of the articular cartilage. Culture of aspirated fluid revealed no growth. This case is from Docplexus editorial team for educative purpose only!