The Cardiovascular
ToolsCalculators

Kocher criteria for paediatric septic arthritis

Probability of septic arthritis of the hip in a child with hip complaints.

Kocher criteria for paediatric septic arthritis
Non-weight-bearing on the affected side
Temperature >38.5 C (101.3 F)
ESR >40 mm/hr
Serum WBC >12,000 /uL
Result0 points

Predicted probability of septic arthritis about <0.2 %.

Probability of septic arthritis
<0.2 %

When to use

  • Differentiating septic arthritis from transient synovitis in a child with an irritable hip.

Formula

One point each: non-weight-bearing, temperature >38.5 C, ESR >40 mm/hr, WBC >12,000/uL. Probabilities: 0 <0.2%, 1 ~3%, 2 ~40%, 3 ~93.1%, 4 ~99.6%.

Pearls and pitfalls

  • Original derivation predates routine CRP; adding CRP >20 mg/L improves discrimination in later validations.

References

  1. Kocher MS, et al. J Bone Joint Surg Am. 1999;81(12):1662-70.