The Phemister triad

A 25-year-old man presented with a 3-month history of a painful swollen left knee joint. It was insidious in onset and progressive in nature; it did not vary throughout the day and the pain was partially relieved with analgesics. There was nothing in the patient's history to suggest a connective tissue disorder, spondyloarthropathy, or diabetes. During the month prior to presentation, he had lost weight and developed a low-grade fever. On investigation, his complete haemogram and blood biochemistry were unremarkable.