For healthcare professionals
Kocher Criteria
The Kocher criteria help tell septic arthritis of the hip (a joint infection) from transient synovitis (an irritable hip without infection) in a child with a painful hip. They count four findings and give a published probability for each count. Kocher and colleagues published them in 1999. This tool is written for clinicians and is not a diagnosis.
Findings
For a child with a painful hip in whom septic arthritis or transient synovitis is being considered. Tick each finding that is present. Nothing you enter leaves this page.
What you will see
How many of the 4 criteria are present and the published probabilities for that count.
Educational only, not medical advice. Not a diagnosis. Testing and treatment decisions belong to the treating team.
Source
Kocher MS and colleagues, Journal of Bone and Joint Surgery (American) 1999. The criteria and the 1999 probabilities are taken from the open-access (CC BY) review of Valisena and colleagues, Microorganisms 2024; the 2004 revalidation probabilities are from Table 2 of Hanna and colleagues, Cureus 2024 (CC BY). The tests check every count against both sets of probabilities.
Validated in
Children with hip pain in whom septic arthritis or transient synovitis is suspected. The original study was a retrospective analysis of 282 patients (Hanna 2024).
Limits
The probabilities come from the study groups and were lower in later studies, for example 59% with all four criteria in one retrospective study and 39.4% in another (Hanna 2024). A review found the evidence insufficient to establish the criteria fully and advises against using them to rule out septic arthritis (Hanna 2024). They may miss infection with Kingella kingae (Valisena 2024). Sources print the fever and ESR cut-offs as both 'over' and 'at least'.
The criteria
Count how many of these four findings are present (Valisena 2024):
- History of fever (over 38.5 °C)
- Not bearing weight on the affected side
- Erythrocyte sedimentation rate (ESR) over 40 mm/h
- Serum white blood cell count over 12,000/mm³
Predicted probability of septic arthritis
| Criteria present | Kocher 1999 | Kocher 2004 revalidation |
|---|---|---|
| 0 | below 0.2% | 2.0% |
| 1 | 3.0% | 9.5% |
| 2 | 40.0% | 35% |
| 3 | 93.1% | 72.8% |
| 4 | 99.6% | 93% |
1999 figures as printed by Valisena and colleagues (Valisena 2024); 2004 figures as printed by Hanna and colleagues (Hanna 2024). The criteria were published by Kocher and colleagues (Kocher 1999).
Worked example: a 5-year-old with a painful hip who has had a fever of 39 °C and will not stand on the leg, with an ESR of 25 mm/h and a white cell count of 9,000/mm³, has 2 of 4 criteria, which corresponds to 40% in the original study and 35% in the revalidation.
What the studies found
A literature review of six studies found that three reported high probabilities, but these were by the original authors or in selected groups, and three with lower probabilities were small. It concluded that the criteria have low specificity and should be used with caution, not as a replacement for joint aspiration (Hanna 2024).
Caird and colleagues added C-reactive protein over 20 mg/L as a fifth criterion (Valisena 2024). This tool uses the original four.
Related calculators
For children with abdominal pain, see the Pediatric Appendicitis Score. For knee injuries, see the Ottawa Knee Rule. Other bedside scores are listed under For healthcare professionals.
Sources
- Valisena S, De Marco G, Vazquez O, et al. The Kocher-Caird Criteria for Pediatric Septic Arthritis of the Hip: Time for a Change in the Kingella Era? Microorganisms. 2024;12(3):550. doi:10.3390/microorganisms12030550. PMID 38543601. Open access (CC BY 4.0). Kocher criteria (fever over 38.5 C, non-weight bearing, ESR over 40 mm/h, WBC over 12,000/mm3); probabilities below 0.2%, 3%, 40%, 93.1%, 99.6%; Caird added CRP over 20 mg/L; Kingella kingae. pmc.ncbi.nlm.nih.gov/articles/PMC10974044/
- Hanna J, Rashid R, Hanna M, et al. Paediatric Septic Arthritis of the Hip and the Efficacy of Kocher's Criteria: A Literature Review. Cureus. 2024;16(8):e66184. doi:10.7759/cureus.66184. PMID 39233979. Open access (CC BY 4.0). Table 2: 2004 revalidation probabilities 2.0%, 9.5%, 35%, 72.8%, 93%; later studies 59.1% and 39.4% with four criteria; 282 patients in the original study. pmc.ncbi.nlm.nih.gov/articles/PMC11373530/
- 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. PMID 10608376. Original paper (cited; the criteria used here are taken from Valisena 2024, CC BY). pubmed.ncbi.nlm.nih.gov/10608376/
Written and maintained by the uncovermyrisk.com editorial team. We do not have a medical reviewer; every claim links to its primary source above. Last reviewed: 2026-11-02. Spotted an error? See About.