Patellar Osteomyelitis Mimicking Cellulitis Successfully Treated Without Surgical Intervention

Osteomyelitis is an inflammatory infection of the bone whose incidence in children has increased over the past decade.It often presents with nonspecific clinical manifestations, and it is often difficult to diagnose.Here, we report the case of a school-aged boy with patellar osteomyelitis caused by methicillinsusceptible Staphylococcus aureus (MSSA) complicated by bacteremia.Blood cultures obtained on admission grew Gram-positive cocci, later identified as MSSA.Magnetic resonance imaging (MRI) revealed areas of high intensity in the left patella and adjacent overlying soft tissues on short tau inversion recovery sequences.Despite his relatively mild clinical presentation, prompt magnetic resonance imaging and blood cultures enabled an early and accurate diagnosis, allowing successful antimicrobial treatment without surgical intervention.This case highlights that in children presenting with unilateral knee pain, patellar osteomyelitis should be considered in the differential diagnosis, and early MRI may facilitate prompt diagnosis and help avoid invasive surgery.