BACKGROUND: Studies of pediatric osteoarticular infections (OAIs) mostly focus on acute hematogenous osteomyelitis (AHO) and acute bacterial arthritis (ABA). A comprehensive descriptive analysis of pediatric OAIs, including subacute, chronic, and non-hematogenous types, is lacking. METHODS: A detailed analysis of all pediatric OAIs was undertaken at 2 academic centers, Hasbro Children's Hospital, Providence, RI, and Nationwide Children's Hospital, Columbus, OH. Infections were classified as AHO (with or without suppurative arthritis), isolated ABA, subacute or chronic hematogenous osteomyelitis (SCHO), non-hematogenous osteoarticular infection (NHI), or hardware-associated osteoarticular infection (HOI). Clinical, radiological, and laboratory characteristics were compared. RESULTS: A total of 582 consecutive cases of OAIs were included: 295 AHO (51%), 88 ABA (15%), 76 NHI (13%), 73 HOI (13%), and 50 SCHO (9%). Median age was significantly higher for HOI (14.5 years), NHI (11.8), and SCHO (10.4) than for AHO (9) and ABA (5) (P <
.001). Patients with AHO or ABA were more likely (P <
.001) to be febrile (each 84%) compared with other groups (45%-56%) and had higher biomarkers of inflammation (white blood cell, erythrocyte sedimentation rate, C-reactive protein). A causative organism was identified in 74% of cases, mostly from tissue specimens (78%). Staphylococcus aureus was the most common organism across infection types (34%-55% of cases), while polymicrobial infection was common in NHI (22%) and HOI (21%). Chronic morbidity complicated infections in 89 (15%) patients, the majority of whom (66%) had SCHO, NHI, or HOI. CONCLUSIONS: SCHO, NHI, and HOI accounted for a significant proportion of pediatric OAIs and contributed disproportionately to chronic morbidity.