title: The Timing of Total Hip Arthroplasty After Intraarticular Hip Injection Affects Postoperative Infection Risk.
abstract: BACKGROUND
  The data regarding any association between preoperative intraarticular steroid injection and risk ofperiprosthetic joint infection (PJI) after total hip arthroplasty (THA) are conflicting. The goal of the present study is to evaluate the association of preoperative intraarticular hip injection before THA on the incidence of postoperative PJI.
  
  
  METHODS
  A national database was queried for patients who underwent THA and those patients who underwent prior ipsilateral hip injection. Three cohorts were created: THA within 3 months of ipsilateral hip injection (n = 829), THA between 3 and 6 months after ipsilateral hip injection (n= 1379), and THA between 6 and 12months after ipsilateral hip injection (n=1160). A control group of THAwithout prior injectionwas created for comparison purposes (n=31,229). The rate of postoperative infectionwas compared between injection cohorts and controls.
  
  
  RESULTS
  The incidence of infection after THA at 3 months (2.41%; odds ratio, 1.9; P = .004) and 6 months (3.74%; odds ratio, 1.5; P < .019) was significantly higher in the patients who underwent hip injection within 3months before THA comparedwith controls. Therewas no significant difference in infection rates in patients who underwent THA between 3 and 6months or 6 and 12months after ipsilateral hip injection compared with controls.
  
  
  CONCLUSIONS
  The present study demonstrates a significant increase in PJI in patients who underwent intraarticular hip injection within 3 months before THA. This association was not noted when THA was more than 3 months after injection.
authors.affiliation: Department of Orthopaedic Surgery, University of Virginia Health System, Box 800159, Charlottesville, Virginia.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Werner
authors.affiliation: Department of Orthopaedic Surgery, University of Virginia Health System, Box 800159, Charlottesville, Virginia.
authors.forename: Jourdan M
authors.initials: JM
authors.lastname: Cancienne
authors.affiliation: Department of Orthopaedic Surgery, University of Virginia Health System, Box 800159, Charlottesville, Virginia.
authors.forename: James A
authors.initials: JA
authors.lastname: Browne
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001170:Arthritis, Infectious / Q000453:epidemiology / Q000209:etiology*; D019644:Arthroplasty, Replacement, Hip; D005260:Female; D006801:Humans; D015994:Incidence; D007270:Injections, Intra-Articular / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011184:Postoperative Period; D016459:Prosthesis-Related Infections / Q000453:epidemiology / Q000209:etiology*; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology
keywords: infection; injection; periprosthetic joint infection; timing of injection; total hip arthroplasty