title: Comparison of one and two-stage revision of total hip arthroplasty complicated by infection: a Markov expected-utility decision analysis.
abstract: BACKGROUND
  Two-stage revisions of total hip arthroplasties complicated by chronic infection result in reinfection rates that are lower than those following single-stage revisions but may also result in increased surgical morbidity. Using a decision analysis, we compared single-stage and two-stage revisions to determine which treatment modality resulted in greater quality-adjusted life years (QALYs).
  
  
  METHODS
  A review of the literature on the treatment of patients with an infection at the site of a total hip arthroplasty provided probabilities; utility values for common postoperative health states were determined in a previously published study. With these data, we conducted a Markov cohort simulation decision analysis. Sensitivity analysis validated the model, and comparisons were made in terms of QALYs.
  
  
  RESULTS
  The twelve-month model favored direct-exchange revision over the two-stage approach, regardless of whether surgeon or patient-derived utilities were used (0.945 versus 0.896 and 0.897 versus 0.861 QALYs for the patient and surgeon models, respectively). Similar results were observed in a lifetime model with a ten-year life expectancy (7.853 versus 7.771, and 7.438 versus 7.362 QALYs, respectively). The findings were found to be robust in sensitivity analyses in which clinically relevant ranges of input variables were used.
  
  
  CONCLUSIONS
  This analysis favored the direct-exchange arthroplasty over the two-stage approach. This study should be considered hypothesis-generating for future randomized controlled trials in which, ideally, health end points will be considered in addition to the eradication of infection.
authors.affiliation: University of Washington, Seattle, Washington, USA.
authors.forename: Christopher F
authors.initials: CF
authors.lastname: Wolf
authors.forename: Ning Yan
authors.initials: NY
authors.lastname: Gu
authors.forename: Jason N
authors.initials: JN
authors.lastname: Doctor
authors.forename: Paul A
authors.initials: PA
authors.lastname: Manner
authors.forename: Seth S
authors.initials: SS
authors.lastname: Leopold
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000379:methods; D015331:Cohort Studies; D003661:Decision Support Techniques; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008390:Markov Chains; D008875:Middle Aged; D011183:Postoperative Complications / Q000175:diagnosis / Q000601:surgery; D016459:Prosthesis-Related Infections / Q000175:diagnosis / Q000401:mortality / Q000601:surgery*; D019057:Quality-Adjusted Life Years; D012008:Recurrence; D012086:Reoperation / Q000379:methods; D018570:Risk Assessment; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome