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Kocher Criteria for Septic Arthritis of the Hip (Children)

Kocher criteria (non-weight-bearing, fever >38.5 °C, ESR >40 mm/h, WBC >12,000) distinguish septic arthritis of the hip from transient synovitis in children. Predicted probability of septic arthritis: 0 criteria 0.2%, 1 3%, 2 40%, 3 93%, 4 99.6%.

Non-weight-bearing on affected side (yes/no, +1)
Temperature (highest) (°C or °F)
ESR (mm/h)
Serum WBC (×10⁹/L or ×10³/µL)

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Interpretation

Result	Meaning
0	0.2%
1	3.0%
2	40.0%
3	93.1%
4	99.6%

Formula

1 point each: non-weight-bearing; temperature >38.5 °C; ESR >40 mm/h; WBC >12 ×10⁹/L. Probabilities from the derivation cohort.

Clinical pearls

Derivation probabilities fell on validation (e.g. 4/4 ≈ 93% in Kocher 2004); treat as risk stratification, not diagnosis.
CRP >2.0 mg/dL (20 mg/L) adds independent value (Caird 2006 modification).
Consider Lyme arthritis in endemic areas.

Examples

kocher criteria non weight bearing temp 39 esr 50 wbc 14 septic hip vs transient synovitis: walking, temp 37.8, ESR 20, WBC 9

FAQ

What are the Kocher criteria?

Inability to bear weight, fever above 38.5 °C, ESR above 40 mm/h and white count above 12,000; more criteria mean higher probability of septic arthritis.

Is septic arthritis ruled out with 0 Kocher criteria?

Probability is very low (0.2% in the derivation cohort), but clinical judgement and follow-up still apply.

Evidence

Kocher MS et al. Differentiating between septic arthritis and transient synovitis of the hip in children: an evidence-based clinical prediction algorithm. J Bone Joint Surg Am 1999;81:1662–70.

Pediatrics & Obstetrics · Reviewed 2026-10-14 · Methodology