Kocher criteria can help to differentiate between spetic arthritis and transient synovitis in a case of non-traumatic painful hip in a child.
A restrospective study in 104 pediatric patients has depicted that meeting 3 out of 4 crtieria would miss 52% cases and is of limited usefulness in detecting septic arthritis of knee in pediatric population. 1Obey MR, Minaie A, Schipper JA, Hosseinzadeh P. Pediatric Septic Arthritis of the Knee: Predictors of Septic Hip Do Not Apply. J Pediatr Orthop. 2019 Nov/Dec;39(10):e769-e772. doi: 10.1097/BPO.0000000000001377. PubMed PMID: 30950940.
Another study has demonstrated the limited utility of Kocher criteria in the adult population. 2Borzio R, Mulchandani N, Pivec R, Kapadia BH, Leven D, Harwin SF, Urban WP. Predictors of Septic Arthritis in the Adult Population. Orthopedics. 2016 Jul 1;39(4):e657-63. doi: 10.3928/01477447-20160606-05. Epub 2016 Jun 13. PubMed PMID: 27286047.
Mnemonic for Kocher Criteria: Walk FEW
1. Walking or weight bearing inability
2. Fever > 101.3°F or > 38.5°c
3. ESR >40 mm/hr
4. WBC >12,000/cu.mm
Probability of septic arthritis with number of criterion met:
- 4 out of 4: 99%
- 3 out of 4: 93 %
- 2 out of 4: 40%
- 1 out of 4: 3%
- 0 out of 4: 0.2%
Caird et.al. (2006) added CRP to the Kocher criteria. CRP ≥ 20 mg/L is another predictor of septic arthritis. The best predictor of septic arthritis is fever followed closely by raised CRP. A study by Walker et.al. revealed that an elevated CRP (2.0mg/dL) and inability to bear weight together resulted in a PPV of 78%. With a CRP threshold of 3.0mg/dL and inability to bear weight, the PPV was 81%. 3Septic arthritis of the pediatric hip: Re-evaluating a predictive algorithm – Justin W. Walker and William HennrikusPediatrics May 2018, 142 (1 MeetingAbstract) 284; DOI: https://doi.org/10.1542/peds.142.1_MeetingAbstract.284
The modified Kocher criteria can be easily remembered using the mnemonic: WAIT
1. WBC
2. Acute phase reactants: ESR and CRP
3. Inability to walk
4. Temperature