The value of detecting serum PCT and IL-6 levels during the perioperative period of primary hip and knee arthroplasty.

Objective: The current study aimed to characterize the variation of serum PCT and IL-6 levels and look the specificity and the sensitivity in diagnosing pneumonia, urinary and superficial surgical site infections during the perioperative period of primary hip and knee arthroplasty. Methods: This observational study included 73 patients undergoing primary hip and knee arthroplasty. Serum Procalcitonin (PCT), and Interleukin-6 (IL-6) were measured preoperatively (D0) and at postoperative day 4 (D4) and day 6 (D6). The sensitivity, specificity and predictive values of PCT and IL-6 were assessed. Results: On comparison of the mean of PCT levels between infection group and non-infection group, a significant difference was seen at D6 (day 6) (p<0.01), but with no significant difference for IL-6. For PCT, the AUC was 0.967 (95% CI, 0.934-1.000), for IL-6 the AUC was 0.806 (95% CI, 0.754-0.859). The PCT value was a significant predictor of infection (AUC>0.9). For PCT, the cut-off point of 0.1385 ng/ml had a sensitivity of 93.3% and a specificity of 97.3%. However, the IL-6 was a less significant predictor for infection (0.7<AUC<0.9). The IL-6 value of 30.215 pg/ml had a sensitivity of 77.8% and specificity of 71.3%. Conclusions: It is valuable to monitor the variation trend of PCT and IL-6 as a marker for possible infection in the early post-operative period. Detecting PCT may be more valuable than using IL-6 in the diagnosis sepsis pathological changes in the perioperative period.