Osteomyelitis and septic arthritis are common pathologies in young children. Because of their skeletal immaturity, children are particularly vulnerable to orthopaedic complications, including limb-length discrepancies, angular deformities, chondrolysis, etc. The primary objective of this study was to review the clinical follow up and outcomes of paediatric patients diagnosed with osteoarticular infections. The secondary purpose was to look for significant differences in the clinical characteristics between the one with and without complications.

Patients' medical charts, hospitalised between 2010 and 2016, were retrospectively reviewed. The inclusion criteria were: patients (1) aged of less than 10 years old (2) treated and followed for osteomyelitis of long bones of upper and lower extremities and/or septic arthritis (3) with at least one year of radiological follow up. The exclusion criterion was: (1) any concomitant chronic diseases. The information collected included demographic and clinical data. A late sequela was defined as a limb-length discrepancy superior to 5 mm or an abnormal articular angulation of more than 5°, or a symptomatic chondropathy. Patients were separated in two groups: with and without complications. Chi-square tests were used for categorical variables and Mann-Whitney U tests for continuous data in order to establish significant differences between both groups.

Of the 401 patients with osteomyelitis and/or septic arthritis treated in our tertiary paediatric hospital over 7 years, 50 met the inclusion criteria. There were 24 girls and 26 boys. The etiological agent was identified in 56% of the cases. Staphylococcus aureus was the predominant causal pathogen (50%), followed by Kingella kingae (19.2%). The mean follow up was 780 days. Six out of 50 (12%) patients had physeal or chondrolytic complications at the latest follow-up. The only significant difference between the 2 groups was the delay between onset of symptoms and initiation of antibiotic therapy (P = 0.039).

Only 12.5% of the patients were followed up at least one year. In the population of 50 skeletally immature patients without comorbidities, 12% had a sequela. The delay in initiating antibiotic treatment was significantly longer in the group with the presence of sequelae.

The results of this study reveal that there were low rates of outpatient follow-up reaching more than a year after an osteoarticular infection, thus raising the question about the importance of a follow up after such a diagnosis. Twelve percent of the patients had a growth or chondrolysis complication and this might be related to the delay before initiating antibiotic treatment.