Predicting the presence of adjacent septic arthritis in children with acute hematogenous osteomyelitis.

INTRODUCTION

This study conducted statistical analysis of clinical data from cases of acute hematogenous osteomyelitis (AHO) with or without concomitant septic arthritis, with the objective of identifying factors that are indicative of concomitant septic arthritis. Predictive models will be developed to predict coexisting infections, with one that is independent of MR findings and another that incorporates MRI data.

METHODS

A retrospective review of 127 children (132 cases of AHO) treated for AHO was performed. All patients underwent MRI. The data encompassed various demographic, clinical, and diagnostic factors. Graphical and logistical regression analysis was used to determine variables independently predictive of adjacent infection. Optimal cutoff values were determined for each variable and a prediction model was created. Finally, the model was applied to our patient database and each patient with isolated AHO, or concomitant infection was stratified based upon the number of positive predictive factors.

RESULTS

The overall incidence of coexisting septic arthritis in patients with AHO was 52.2% (69/132). Four risk factors (age below 4 years, a history of preceding infection, platelet count > 390.5 × 10^9/L, and absolute neutrophil count < 5.45 × 10^3 cells/ml) were found to be predictive of concomitant infection and were included in the algorithm. Patients with ≥ 2 risk factors were classified as high risk for AHO with concomitant infection (Sensitivity: 79.41% (95% CI: [64.10%, 94.71%]), Specificity: 76.56% (95% CI: [58.61%, 94.51%]), Positive Predictive Value (PPV): 78.26% (95% CI: [63.43%, 93.09%]), and Negative Predictive Value (NPV): 77.78% (95% CI: [61.02%, 94.54%]). In MRI, joint effusion was the primary indicator of concomitant septic arthritis in patients with AHO, followed by the absence of subperiosteal abscess. The presence of subperiosteal abscess in the absence of joint effusion was highly correlated with isolated AHO, showing a 100% occurrence rate (39/39).

CONCLUSIONS

Our study successfully identified several risk factors and radiologic signs associated with concomitant septic arthritis in patients with AHO. These findings can assist clinicians in early recognition and management of coexisting infections, especially in situations where MRI is not readily available or when its findings are inconclusive. Timely identification of these factors is crucial for appropriate treatment planning and improved patient outcomes.