Correlation of native knee joint septic arthritis and bacteremia: A retrospective study

Objectives: Septic arthritis is an orthopedic emergency, delayed treatment results in rapid, and irreversible joint destruction with significant morbidity and mortality. The correlation between the infectious organism(s) isolated from blood and synovial fluid remains unclear. Native joint septic arthritis (NJSA) is often secondary to bacteremia and other contiguous sources of infection. This investigation examined the correlation in infectious organisms between blood and synovial fluid in patients with NJSA and concurrent bacteremia. Methods: A retrospective chart review was performed on 712 NJSA cases at an urban, level-one trauma center. Patients diagnosed with septic knee arthritis through synovial fluid analysis with white blood cell count >50,000 and/or positive culture from the knee joint on aspiration were included in the study. The organism identified on blood culture in the bacteremic patient was then correlated to the organism found on synovial fluid analysis. Results: We identified 104 patients at our institution with septic knees; 48 with bacteremia and 56 that did not have bacteremia. Of these patients with bacteremia, 34 patients (70.8%) had the same organism isolated in the knee and the blood. This correlation was statistically significant, with P = 0.003. Furthermore, patients with bacteremia underwent a mean of 1.85 +/- 0.76 debridement procedures versus 1.21 +/- 0.80 procedures in those without (P P = 0.001). Conclusion: This study shows a correlation between the organism isolated from the knee and the blood in patients with NJSA in conjunction with bacteremia as well as a correlation between the bacteremic patient and the number of surgical interventions required per patient.