🦴 Kocher Criteria (Septic Arthritis of Hip)
Differentiate septic arthritis from transient synovitis of the hip in children (Kocher criteria).
Clinical takeaway
Higher counts warrant joint aspiration.
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When to use
Estimate the probability of a septic hip in an irritable child.
How it works
Non-weight-bearing, ESR > 40, temperature > 38.5 °C, WBC > 12 (1 each). Probability rises from < 0.2% (0) to ~99% (4).
Key points
- Higher counts warrant joint aspiration.
- CRP adds discriminatory value.
- A low count does not fully exclude infection.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Non-weight-bearing on affected side | No |
|---|---|
| ESR > 40 mm/h | No |
| Temperature > 38.5 °C | No |
| WBC > 12 ×10⁹/L | No |
→Predictors0/4
- Probability of septic arthritis：< 0.2%
- Note：Higher counts warrant joint aspiration; clinical judgement and CRP add information.
| Non-weight-bearing on affected side | Yes (+1) |
|---|---|
| ESR > 40 mm/h | Yes (+1) |
| Temperature > 38.5 °C | Yes (+1) |
| WBC > 12 ×10⁹/L | Yes (+1) |
→Predictors4/4
- Probability of septic arthritis：99%
- Note：Higher counts warrant joint aspiration; clinical judgement and CRP add information.
Frequently asked questions
- What is Kocher Criteria (Septic Arthritis of Hip)?
- Differentiate septic arthritis from transient synovitis of the hip in children (Kocher criteria).
- How is Kocher Criteria (Septic Arthritis of Hip) calculated? What is the core formula?
- Non-weight-bearing, ESR > 40, temperature > 38.5 °C, WBC > 12 (1 each). Probability rises from < 0.2% (0) to ~99% (4).
- When is Kocher Criteria (Septic Arthritis of Hip) used?
- Estimate the probability of a septic hip in an irritable child.
- What are the key clinical points for Kocher Criteria (Septic Arthritis of Hip)?
- Higher counts warrant joint aspiration. CRP adds discriminatory value. A low count does not fully exclude infection.
- What are the limits and cautions when using Kocher Criteria (Septic Arthritis of Hip)?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is Kocher Criteria (Septic Arthritis of Hip) calculated in practice? Can you show a worked example?
- Inputs: Non-weight-bearing on affected side No, ESR > 40 mm/h No, Temperature > 38.5 °C No, WBC > 12 ×10⁹/L No → Result: Predictors 0 /4（Probability of septic arthritis: < 0.2%, Note: Higher counts warrant joint aspiration; clinical judgement and CRP add information.） Inputs: Non-weight-bearing on affected side Yes (+1), ESR > 40 mm/h Yes (+1), Temperature > 38.5 °C Yes (+1), WBC > 12 ×10⁹/L Yes (+1) → Result: Predictors 4 /4（Probability of septic arthritis: 99%, Note: Higher counts warrant joint aspiration; clinical judgement and CRP add information.）