Comparison Between Septic Arthritis Alone and Coexisting with Other Bone and Joint Infections in Pediatric Patients: A Retrospective Review.

Abstract

Background: It is unclear whether coexisting septic arthritis and osteomyelitis (CSAO) differs from septic arthritis (SA) alone in terms of susceptible age groups, clinical and paraclinical presentations, and prevalence. This study aimed to compare patients with isolated SA with those presenting with CSAO, determine the efficacy of different parameters used to distinguish those diagnoses, and investigate the prevalence of CSAO due to Kingella kingae.

Methods: The study retrospectively included all patients treated for SA over a 17-year period at Geneva University Hospitals. Clinical, biological, and bacteriological data were analyzed. Magnetic resonance imaging (MRI) was reviewed for all patients to identify those with coexisting osteomyelitis. Comparisons between patients with isolated SA and those with CSAO were performed using the unpaired Mann-Whitney U for continuous outcomes (reported with median [interquartile range]) and the Pearson χ² tests for dichotomous outcomes (reported with n [%]).

Results: Of 247 patients with osteoarticular infections, 177 with SA fulfilled our inclusion criteria. Of these, 124 had SA alone, and 53 (29.9%) had a CSAO. There were no statistically significant differences between the 2 groups regarding sex, age, and clinical and paraclinical results. When coexisting osteomyelitis was present, 51% of cases were acute and 49% were subacute. Bone infection was found in the metaphyses of 21 patients (39.6%), the epiphyses of 11 (20.8%), and was transphyseal in 10 (18.9%). Whatever the infection location, K. kingae was the most common pathogen found in both groups (48% of SA, 43% of CSAO, p = 0.651).

Conclusions: This study showed that CSAO is common in children, especially among those younger than 4 years, with an unexpectedly high prevalence of subacute osteomyelitis. This should encourage caregivers to use MRI more extensively in diagnostic processes. Clinical and paraclinical data did not contribute to differentiate CSAO from SA. The widespread presence of K. kingae as a pathogen in both groups supports the advice to systematically use polymerase chain reaction techniques in children younger than 4 years of age.

Level of evidence: Level III. See Instructions for Authors for a complete description of levels of evidence.