Episode 170.0 – Septic Arthritis

Septic arthritis requires high clinical suspicion in the emergency department, as delayed diagnosis leads to irreversible joint destruction and significant mortality risks. While classic presentations involve a single, warm, tender joint with fever, clinicians must recognize that many patients lack these findings, particularly those with prosthetic joints or immunosuppression. Arthrocentesis remains the gold standard for diagnosis, though no single synovial white blood cell count provides a definitive cutoff; clinicians should consider 30,000 to 50,000 cells/µL for native joints and lower thresholds for prostheses. Empiric antibiotic therapy, covering MRSA and Gram-negative organisms, should be initiated promptly after joint aspiration to preserve culture accuracy. Because septic arthritis constitutes an orthopedic emergency, early consultation for potential surgical washout is essential for all suspected cases, regardless of the initial clinical presentation.