Pathogen or contaminant? Distinguishing true infection from synovial fluid culture contamination in patients with suspected septic arthritis.

This is the first study of its kind looking at clinical features and outcomes of patients with contaminated SF. These patients present with less severe disease, have better outcomes, and receive new rheumatologic diagnoses in more than a third of cases within 1 year. We recommend a conservative approach for patients with suspected contaminated SF, mild symptoms, and no bacterial growth within the first 48 h.