Mildly decreased preoperative bilirubin levels are considered as risk factors for periprosthetic joint infection after total hip and knee arthroplasty

Background and Purpose Many blood biomarkers are routinely assessed before joint arthroplasty, but only few are commonly used to guide surgeons in determining patients most at risk of periprosthetic joint infection (PJI). The objective of this study was to investigate the correlation between preoperative bilirubin level and PJI after hip and knee arthroplasty. Methods A retrospective analysis was performed on patients undergoing revision hip and knee arthroplasty at our hospital from January 2016 to December 2019. Laboratory biomarkers were collected before the primary arthroplasty, as well as general patient information. The correlation between the above blood biomarkers and postoperative PJI was analyzed. Results A total of 72 patients (30 hips/42 knees) were analyzed, including 39 patients with PJI and 33 patients without PJI. Except for total bilirubin (TB) and direct bilirubin (DB), there was no significant difference between the remaining laboratory biomarkers. The preoperative TB and DB in the PJI group were 10.84 ± 0.61 µmol/L and 3.07 ± 0.19 µmol/L, respectively, which were lower than those in the non-PJI group (14.68 ± 0.75 µmol/L and 4.70 ± 0.39 µmol/L, p = 0.0001 and 0.0002). The AUC of preoperative TB to predict PJI was 0.7552 (p = 0.0002, cutoff = 11.55 µmol/L, sensitivity = 66.67%, specificity = 75.76%, PPV = 76.47%, NPV = 65.79%). Meanwhile, the AUC of preoperative DB was 0.7603 (p = 0.0001, cutoff = 4.00 µmol/L, sensitivity = 84.62%, specificity = 54.45%, PPV = 68.75%, NPV = 75%). Conclusions The serum levels of TB and DB before the primary arthroplasty of PJI patients were lower than those non-PJI patients, and the preoperative values lower than 11.55 µmol/L and 4.00 µmol/L could be considered as risk factors for postoperative PJI.