Neutrophil-lymphocyte and C reactive protein-albumin ratios as predictors of re-surgery in adult native knee septic arthritis

Objectives. Septic arthritis is a medical emergency with a mortality rate of approximately 10%, the knee being the most commonly affected joint (about 50% of cases). The systemic inflammatory response caused by septic arthritis may be affected by the severity of the infection or the success of surgical joint debridement. Materials and Methods. This article was a retrospective study on patients admitted to our hospital (between 2013 and 2020) with septic arthritis of the knee. Patients were diagnosed based on history, examination, blood test results, and knee aspirate fluid. The patient's response to antibiotic therapy was monitored in the outpatient setting using serological markers. Results. Of the 48 patients included in the study, 26 were male, and 22 were female. Based on the ROC analysis, the optimal cutoff value of preoperative NLR was 8.33. The AUC was 0.782 for postoperative NLR level (95% CI,0,626–0.938; p:0.009) and 0.922 for postoperative CAR level (95% CI,0.844–0.999; p <0.001). Postoperative NLR and CAR cutoff values are 15.4 and 115, respectively. Conclusions. Preoperative NLR elevation in septic arthritis may be associated with recurrent surgical debridement postoperatively. In addition, postoperative NLR and CAR values can predict debridement rates in patients after septic arthritis surgery.