A 10 year old boy presents with a painful right knee for 10 days, fever for 1 day and refusal to bear weight on the affected limb since waking up today. He is otherwise asymptomatic. His parents recall that he slipped and impacted his knee on the floor around a month ago, but was fine afterwards. His medical and birth histories are unremarkable. All immunizations are up to date.
WBC/DC: 14,000/mm3 Neutrophils: 90% Lymphocytes: 8% Hb: 13.2 g/dL Hct (PCV): 38% Platelets: 204,000/mm3 Blood film (picture) : Normal
ESR: 70 mm/1h (high) CRP: 48 ng/l (high)
The X-ray of the right knee joint appears normal.
Increased blood flow to the distal femur is noted, while increased tracer uptake can be seen in the distal femoral metaphysis just proximal to the epiphyseal growth plate. No other abnormalities are noted.