title: Leukocyte Esterase Strip Test Can Predict Subsequent Failure Following Reimplantation in Patients With Periprosthetic Joint Infection.
abstract: Leukocyte esterase (LE) strip test is an accurate marker for diagnosing periprosthetic joint infection (PJI). This study aims to determine if LE is a good predictor of persistent infection and/or subsequent failure in patients undergoing reimplantation.
  
  
  
  This single-institution study prospectively recruited and retrospectively analyzed 109 patients who underwent two-stage exchange treatment of PJI, from 2009-2016, and had an LE test performed at time of reimplantation. LE results of "2+" were considered positive. Ninety-five patients had 90-day minimum follow-up to assess treatment failure, defined by Delphi criteria. Eighteen patients were excluded due to blood contamination of LE test, resulting in a final cohort of 77 patients (mean follow-up 1.76 years).
  
  
  
  Of the final cohort, 19 patients (24.7%) experienced subsequent failure. At reimplantation, LE test was positive in 22.2% of culture-positive and 4.4% of culture-negative cases. The LE test was negative in all patients who had not failed at latest follow-up, yielding sensitivity, specificity, positive predictive value, negative predictive value, and AUC of 26.3%, 100%, 100%, 87.5%, and 0.632, respectively; in comparison, MSIS criteria respectively yielded 25.0%, 87.3%, 27.6%, 85.8%, and 0.562 (P = .01 for specificity). Kaplan-Meier curves revealed higher failure rate in patients who had a positive LE test at time of reimplantation (P < .001).
  
  
  
  There is a dire need for an accurate diagnostic test to determine optimal timing of reimplantation in patients undergoing surgical treatment for PJI. The current study suggests that a positive LE test may be indicative of persistence of infection and results in a higher rate of subsequent failure.
authors.affiliation: The Rothman Institute at Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Kheir
authors.affiliation: The Rothman Institute at Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Colin T
authors.initials: CT
authors.lastname: Ackerman
authors.affiliation: The Rothman Institute at Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Tan
authors.affiliation: The Rothman Institute at Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Andrea
authors.initials: A
authors.lastname: Benazzo
authors.affiliation: The Rothman Institute at Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Eric H
authors.initials: EH
authors.lastname: Tischler
authors.affiliation: The Rothman Institute at Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Javad
authors.initials: J
authors.lastname: Parvizi
mesh_terms: D019540:Area Under Curve; D001170:Arthritis, Infectious / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D002265:Carboxylic Ester Hydrolases / Q000097:blood*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D016459:Prosthesis-Related Infections / Q000097:blood / Q000175:diagnosis*; D012092:Replantation; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013582:Synovial Fluid; D017211:Treatment Failure
chemical_list: D015415:Biomarkers; C021443:leukocyte esterase; D002265:Carboxylic Ester Hydrolases
keywords: diagnostic test; hip; knee; leukocyte esterase; periprosthetic joint infection; reimplantation