title: Risk factors for failed two-stage procedure after chronic posttraumatic periprosthetic hip infections.
abstract: BACKGROUND
  The aim of the study was to identify risk factors of failed two-stage procedures in cases of chronic posttraumatic periprosthetic hip infections.
  
  
  METHODS
  Between 2006 and 2008, 26 patients with chronic posttraumatic periprosthetic infections after hip arthroplasty were included. In all cases operative bacterial eradication was initiated. The therapy was carried out according to a standardized treatment protocol including the eradication of the bacterial infection and the prosthetic replacement after three negative intra-operative specimens as a two-stage procedure. Follow-up was performed at least 2 years after revision procedure.
  
  
  RESULTS
  Twelve patients showed no signs of infectious recurrence 2 years after prosthetic hip revision therapy (46 %) and were assigned to group I. Group II is constituted by the other 14 patients (54 %). Four of them (16 %) suffered from an infectious recurrence after prosthetic hip replacement, ten patients (38 %) were characterised by a failed bacterial eradication. The spectrum of pathogens showed a significantly higher resistance pattern (p = 0.001) in group II, with a majority of methicillin-resistant Staphylococcus epidermidis (MRSE) and highly resistant Pseudomonas. In addition, patients of group II offered significantly higher American Society of Anesthesiology (ASA) scores (p = 0.015), the body mass index (BMI) was significantly elevated (p = 0.031) and received a significantly higher number of operative procedures (p = 0.016).
  
  
  CONCLUSIONS
  A reduced general state of health, a high BMI and highly resistant pathogens are the main risk factors for a failed two-stage procedure after chronic posttraumatic periprosthetic hip infections. Therefore, different treatment strategies are required for a defined subgroup of patients.
authors.affiliation: Berufsgenossenschaftliche Unfallklinik, Trauma center Murnau, Prof.-Küntscher-Strasse 8, Murnau, Germany. uli.spiegl@gmx.de
authors.forename: Ulrich
authors.initials: U
authors.lastname: Spiegl
authors.forename: Jan
authors.initials: J
authors.lastname: Friederichs
authors.forename: Robert
authors.initials: R
authors.lastname: Pätzold
authors.forename: Matthias
authors.initials: M
authors.lastname: Militz
authors.forename: Christoph
authors.initials: C
authors.lastname: Josten
authors.forename: Volker
authors.initials: V
authors.lastname: Bühren
mesh_terms: D000077:Acetabulum / Q000293:injuries*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D001424:Bacterial Infections / Q000209:etiology* / Q000382:microbiology / Q000628:therapy; D002908:Chronic Disease; D005260:Female; D005264:Femoral Fractures / Q000601:surgery*; D006620:Hip Fractures / Q000601:surgery; D006621:Hip Joint / Q000382:microbiology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011475:Prosthesis Failure; D016459:Prosthesis-Related Infections / Q000209:etiology* / Q000382:microbiology / Q000628:therapy; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors; D017211:Treatment Failure; D055815:Young Adult