* Differential * Traumatic causes: non-accidental trauma, fracture, dislocation, sprain, strain, tendonitis, osgood schlatter * Non-traumatic causes: septic arthritis, transient synovitis, osteomyelitis, SCFE, LCP disease, rheumatologic disease, bony tumors * Work-up * XRay * Labs to evaluate for septic arthritis – CBC BMP ESR CRP * Kocher Criteria * Non-weight bearing * Fever >38.5C * ESR >40 * WBC >12 * Kocher Criteria Statistics * 0 points: 0.2% (or 2% in prospective studies) * 1 point: 3% (or 9% in prospective studies) * 2 points: 40% * 3 points:93% * 4 points: 99% * Septic Arthritis DX * >50,000 WBC * Age 0-3mo : group B strep * Age 3mo – 12 years: Staph Aureus * Age 12-18 years: Gonorrhea * Sickle Cell Disease: Salmonella