Acute hematogenous osteomyelitis and septic arthritis in children: clinical characteristics and outcomes study.

OBJECTIVE: To evaluate the clinical features, causative pathogens and outcomes-related to acute hematogenous osteomyelitis and septic arthritis in pediatric patients. MATERIAL AND
METHOD: The authors conducted a retrospective cohort study of patients under 15 years of age with diagnosis of acute hematogenous osteomyelitis (AHO) and/or septic arthritis (SA), treated at Queen Sirikit National Institute of Child Health from 1996 to 2006. Demographic data, clinical characteristics, bacterial spectrum, and outcomes were collected. Potential risk factors for osteoarticular sequelae in the patients who had more than 2 years of follow-up were analyzed.
RESULTS: One hundred and twenty-nine patients met the diagnostic criteria which included 51 cases with SA, 35 cases with AHO and 37 cases with both SA and AHO. The patient's age ranged between 1 day and 13 years 4 months, comprising 37 (28.6%) of newborns, 28 (21.7%) of > 1-12 months, 18 (14%) of > 1-3 years and 46 (35.7%) of > 3-15 years. Causative bacteria were found in 103 of 129 patients (80%), the two most common pathogens were methicillin-sensitive Staphylococcus aureus (MSSA) in 48 (46.6%) and methicillin-resistant Staphylococcus aureus (MRSA) in 18 (17.5%) cases. The initial temperature on admission day was high (> 37.5 degrees C) in only one-third of newborns, one-half of infants and two-thirds of the older group. The duration of antibiotic administration ranged between 21 and 56 days (mean 42 days). Arthrotomy or drainage and bone or joint aspiration underwent in 62% and 17% of cases respectively. Outcomes of 79 patients who had more than 2 years of follow-up identified osteoarticular sequelae in 23 patients (29%) that consisted of avascular necrosis of epiphysis, limb-length discrepancy and pathologic fractures. Univariate analysis for potential risk factors compared between sequelae and without sequelae groups demonstrated significant association with more than 1 week duration of presenting symptoms, newborn age group, hip joint infection, infection with MRSA and more than 3 days delayed treatment with appropriate antibiotics.
CONCLUSION: MSSA was the most common bacterial pathogen causing pediatric osteoarticular infections in all age groups but was second to MRSA in the newborn group. Osteoarticular sequelae were avascular necrosis of epiphysis, limb length discrepancy, and pathologic fracture which were significantly related to longer duration of presenting symptoms, newborn age group, hip joint involvement, MRSA infection and delayed administration of appropriate antibiotics.