title: Efficacy of revision surgery for the dislocating total hip arthroplasty: report from a large community registry.
abstract: BACKGROUND
  Historically, achieving stability for the unstable total hip arthroplasty (THA) with revision surgery has been achieved inconsistently. Most of what we know about this topic comes from reports of high-volume surgeons' results; the degree to which these results are achieved in the community is largely unknown, but insofar as most joint replacements are done by community surgeons, the issue is important.
  
  
  OBJECTIVE
  We used a community joint registry to determine: (1) the frequency of repeat revision after surgery to treat the unstable THA; (2) what surgical approaches to this problem are in common use in the community now; (3) are there differences in repeat revision frequency that vary by approach used; and (4) has the frequency of repeat revision decreased over time as surgical technique and implant options have evolved?
  
  
  METHODS
  We reviewed 6801 primary THAs performed in our community joint registry over the last 20 years. One hundred eighteen patients (1.7%) with a mean age of 67 years were revised within the registry for instability/dislocation. Failure was defined as a return to the operating room for rerevision surgery for instability. Minimum followup was 2 years (average, 9.4 years; range, 2-20 years) with six patients having incomplete followup. The frequency of rerevisions was calculated and compared using Pearson's chi-square test. Cumulative rerevision rates were calculated using the Kaplan-Meier method and types of revision procedures were compared using the log-rank test.
  
  
  RESULTS
  The initial revision procedure was successful in 108 patients (92%); 10 patients underwent repeat surgery for recurrent dislocation after their initial revision surgery. The most frequently performed procedure was revision of the head and liner only (35 of 118 [30%]); constrained devices were used in 19% (22 of 118) of the procedures. There was no difference in the cumulative rerevision rates for instability or dislocation by type of revision procedure performed. Six of 22 constrained liners were rerevised for varying indications. There was no difference in frequency of repeat revision for instability between those patients revised for THAs performed before 2003 and those managed more recently.
  
  
  CONCLUSIONS
  Revision surgery for unstable THA is successfully managed in the community with a variety of surgical interventions. Identifying the reason for dislocation and addressing the source remain paramount. Constrained liners should be used with caution; although typically used in the most problematic settings, rerevision for a variety of failure modes remains troublesome.
  
  
  METHODS
  Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
authors.affiliation: Department of Orthopaedic Surgery, University of Minnesota Medical School, Minneapolis, MN, USA.
authors.forename: Tiare
authors.initials: T
authors.lastname: Salassa
authors.forename: Daniel
authors.initials: D
authors.lastname: Hoeffel
authors.forename: Susan
authors.initials: S
authors.lastname: Mehle
authors.forename: Penny
authors.initials: P
authors.lastname: Tatman
authors.forename: Terence J
authors.initials: TJ
authors.lastname: Gioe
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000295:instrumentation*; D001696:Biomechanical Phenomena; D016009:Chi-Square Distribution; D003153:Community Health Services; D005260:Female; D006617:Hip Dislocation / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology / Q000601:surgery*; D006621:Hip Joint / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D015994:Incidence; D007593:Joint Instability / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology / Q000601:surgery*; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D010818:Practice Patterns, Physicians'; D011475:Prosthesis Failure; D016059:Range of Motion, Articular; D012042:Registries; D012086:Reoperation; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome