Kocher Criteria (septic arthritis vs transient synovitis)
Kocher criteria (Kocher 1999): non-weight-bearing, fever, ESR > 40, and WBC > 12 predict the probability of septic arthritis of the hip in a child.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Non-weight-bearing
- Yes
- Fever > 38.5 °C
- Yes
Result: Kocher 2/4 predictors present: predicted probability of septic arthritis 40.0%.
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Predictors
- non-weight-bearing, temperature > 38.5 C, ESR > 40 mm/hr, serum WBC > 12,000 cells/uL.
- Probability
- 0 -> < 0.2%; 1 -> 3.0%; 2 -> 40.0%; 3 -> 93.1%; 4 -> 99.6% predicted septic arthritis (development cohort). Joint-aspiration decision support.
What you enter
- Non-weight-bearing
- Fever > 38.5 °C
- ESR > 40 mm/hr
- WBC > 12 ×10⁹/L
How this is calculated
Kocher MS, Zurakowski D, Kasser JR. 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(12):1662-1670. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.