Can't walk

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.

Select Relevant Investigations
Full blood count

Performed

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 & CRP

Performed

ESR: 70 mm/1h (high)
CRP: 48 ng/l (high)
X-Ray R/Knee Joint

Performed

The X-ray of the right knee joint appears normal.
Isotope bone scan

Performed

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.

Select Relevant Management
IV Antibiotics
Surgical debridement stat
NSAIDS
Immobilization of limb stat