title: Periprosthetic joint infection diagnosis: a complete understanding of white blood cell count and differential.
abstract: Recent research has raised doubts regarding the utility of serum white blood cell count (WBC) for diagnosis of periprosthetic joint infection (PJI). As synovial WBC and neutrophil (PMN) percentage have been adopted as accurate markers of PJI, this study investigated the correlation of WBC in serum versus joint fluid and diagnostic value of all WBC levels for failed arthroplasty patients. 153 patients (73 PJI) undergoing revision knee arthroplasty were identified. Weak correlations between joint fluid and serum for WBC (R = 0.19), PMN count (R = 0.31), and lymphocyte count (R = -0.22) were observed. Diagnostic accuracy of PMN (93%) and WBC (93%) synovial count relative to serum was similar to synovial WBC (93%) and PMN% (95%) alone. Serum WBC analysis does little to improve the accurate diagnosis of PJI.
authors.affiliation: The Rothman Institute of Orthopedics at Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Zmistowski
authors.forename: Camilo
authors.initials: C
authors.lastname: Restrepo
authors.forename: Ronald
authors.initials: R
authors.lastname: Huang
authors.forename: William J
authors.initials: WJ
authors.lastname: Hozack
authors.forename: Javad
authors.initials: J
authors.lastname: Parvizi
mesh_terms: D019645:Arthroplasty, Replacement, Knee; D003937:Diagnosis, Differential; D006801:Humans; D007958:Leukocyte Count; D011237:Predictive Value of Tests; D016459:Prosthesis-Related Infections / Q000097:blood* / Q000175:diagnosis*; D012372:ROC Curve; D012680:Sensitivity and Specificity; D013582:Synovial Fluid / Q000737:chemistry; D017211:Treatment Failure