Kocher Criteria for Septic Arthritis

Why Use

Differentiation between septic arthritis and transient synovitis of the hip in children can be difficult given their similar, non-traumatic presentations. The Kocher criteria can quickly identify particular subsets of patients who need urgent orthopedic consultation or can be readily observed.

When to Use

The Kocher Criteria can be applied to all pediatric patients with an acutely irritable hip in whom septic arthritis and transient synovitis are in the differential diagnosis.

Formula

Pearls / Pitfalls

The Kocher Criteria was derived to identify factors important in distinguishing septic arthritis and transient synovitis. Patients falling on either extreme of the criteria can be readily ruled in or out for septic arthritis in the right clinical setting. Patients in the intermediate range may need further work-up or intervention. Criteria did not perform as well in the validation study though may still be clinically useful for those on either extreme of the criteria.

Management

Consider diagnostic hip aspiration in patients with a clinical concern for septic arthritis that have at least one predictor for septic arthritis If there is a high clinical suspicion do not delay orthopedic consultation. Consider observation and/or discharge with close follow-up in well-appearing patients with a low clinical suspicion for septic arthritis and no predictors present.

Critical Actions

Patients meeting none or all of the Kocher criteria can potentially be discharged (0 predictors) or require urgent orthopedics consultation for washout (4 predictors). Those with some predictors may require hip arthrocentesis.

Advice

Obtain a thorough history and physical exam on all pediatric patients presenting with an acutely irritable hip, paying particular concern to presence or history of fever and inability to bear weight. Draw a CBC, ESR and CRP in all patients with a clinical concern for septic arthritis or transient synovitis.

More Information

+ 1 criterion - 3% probability for septic arthritis + 2 criteria - 40% probability for septic arthritis + 3 criteria - 93% probability for septic arthritis + 4 criteria - 99.6% probability for septic arthritis