Background: Septic arthritis of the elbow in children is a rare but important musculoskeletal infection, and there is little published data to guide treating clinicians. The purpose of this study was to describe the clinical presentation and diagnostic findings, associated pathology, and microbiological profile of septic arthritis of the elbow in a pediatric population.
Methods: We retrospectively analyzed a consecutive series of children who had an elbow arthrocentesis for presumed septic arthritis and whose joint aspirates were positive for microbial growth. Data collected included demographics, presenting signs and symptoms, imaging, and laboratory data, including culture results.
Results: Twelve children underwent diagnostic arthrocentesis of the elbow joint for septic arthritis at an average age of 6 years and 9 months (range, 2 mo to 13 y and 7 mo). Every child had pain, localized erythema and edema, and restricted range of motion; 10/12 were febrile. Mean duration of symptoms prior to joint tap was 4 days (range, 1 to 14 d). Concurrent osteomyelitis was found in 7 patients, as confirmed with magnetic resonance imaging (MRI): 5 at initial presentation and 2 after readmission for persistent symptoms. Causative pathogens were MSSA (7), MRSA (2), Group G streptococcus (1), Pseuodomonas aureginosa (1), and Streptococcus pneumonia (1). ESR was >40 mm/h in 8/11 patients, CRP was >2 mg/dL in all patients, and synovial WBC count was >50,000 cells/mm in 8/9 patients. One patient developed fulminant sepsis during hospitalization and 2 children were readmitted within 30 days of discharge for unrecognized osteomyelitis and/or recurrence of septic arthritis of the elbow.
Conclusion: In 12 children studied with septic arthritis, S. aureus was the most common pathogen. Diagnosis is often delayed, and in most cases inflammatory markers were elevated (ESR>40 mm/h, CRP>2 mg/dL). Concomitant osteomyelitis is quite common, and therefore magnetic resonance imaging should be considered as part of the diagnostic work-up for this condition.
Level of evidence: Level IV—Case series.