Pediatric Septic Arthritis of the Knee due to Fusobacterium necrophorum in a Patient with Down Syndrome: A Case Report.

Fusobacterium necrophorum is a part of the normal oral flora and a rare cause of septic arthritis, typically associated with recent oropharyngeal infection. However, patients with immune dysregulation such as those with Down syndrome may develop isolated septic arthritis due to transient hematogenous seeding.