The diagnostic value of C-reactive protein (CRP) and the serum white blood cell (WBC) count is still barely defined for decision making during septic two-stage revision surgery of hip arthroplasty. We, therefore, compared these values between stages as well as between the groups without and with reinfection in 117 patients. A total of 106 patients were reinfection-free (91%). The median follow-up was 51 months. With a ΔCRP of -10 mg/L and a ΔWBC count of -1000/µL, a significant decrease between stages (p = 0.001) could be observed. When comparing the CRP and WBC count values between groups, however, no significant difference was found at stage one, stage two and even the difference between these two time points (reinfection-free ΔCRP of -11 mg/L and ΔWBC count of -1000/µL vs. reinfection ΔCRP of -5 mg/L (p = 0.131) and ΔWBC count of -1100/µL) (p = 0.424). The diagnostic value was poor for the calculated parameters (area under the curve (AUC) 0.5-0.6). The courses of the mean CRP values of both groups were similar. We conclude that the CRP and WBC count are not helpful to guide the decision making in individual cases.
Keywords: CRP; bone and joint infections; hip arthroplasty; infection parameters; orthopedic infections; periprosthetic joint infection; two-stage revision; white blood cell count.