Kocher Criteria for Septic Arthritis : Mnemonic

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. 1

Another study has demonstrated the limited utility of Kocher criteria in the adult population. 2

kocher criteria

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:

  1. 4 out of 4: 99%
  2. 3 out of 4: 93 %
  3. 2 out of 4: 40%
  4. 1 out of 4: 3%
  5. 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%. 3

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


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