In July 2004, we reviewed a 21 month old Anglo-Caribbean child who presented to our paediatric unit with a limp of his left leg. He had no history of trauma and was otherwise asymptomatic. Blood tests were normal apart from a raised erythrocyte sedimentation rate (ESR) of 15 mm/h, rising to 34 mm/h over a four week period.

Plain radiograph of his left foot revealed an …