Background: This observational study systematically used magnetic resonance imaging (MRI) to determine the prevalence of concomitant osteomyelitis and its influence on clinical outcomes in cases of pediatric septic arthritis (SA) of the hip. Methods: We retrospectively analyzed the demographic, clinical, microbiological, and radiographic data of 58 children treated for SA of the hip who underwent systematic MRI between 2000 and 2025. Patients were categorized into 2 groups: isolated septic arthritis and septic arthritis with concomitant osteomyelitis. The clinical and laboratory parameters, causative pathogens, and treatments were compared between the groups. Results: Concomitant osteomyelitis was identified with MRI in 43% (25) of the 58 patients, while radiographs detected it in only 16%. Demographic, clinical, and inflammatory parameters were statistically similar between the groups. Kingella kingae was the most commonly identified pathogen (37.9%), and Staphylococcus aureus and Streptococcus spp. were more frequently associated with repeat surgery. No significant differences in complication rates, treatment duration, or outcomes were found between the groups. Conclusions: The systematic use of MRI revealed concomitant osteomyelitis in >40% of cases of pediatric SA. However, the presence of osteomyelitis was not associated with worse outcomes, suggesting that factors related to the microorganism profile or virulence must contribute substantially to disease severity. Nonetheless, MRI should be considered early in any diagnostic work-up of pediatric SA of the hip. Level of Evidence: Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.
Khan et al. (Tue,) studied this question.