title: Primary total hip arthroplasty revision due to dislocation: prospective French multicenter study.
abstract: BACKGROUND
  Dislocation following total hip arthroplasty (THA) may require surgical revision, and is one of the most frequent causes for revision in national registers. The goals of this study were to determine the characteristics of revision THA for dislocation and identify the typical features of hips revised due to dislocation.
  
  
  METHODS
  A prospective multicenter study (30 centers) was performed in first revision THA performed between January 1, 2010 and December 31, 2011 (multiple revisions were excluded).
  
  
  RESULTS
  Two hundred nineteen (10.4%) of all first revisions (2153 cases in 2107 patients) were for dislocation, which was the fifth cause of revision. There were 135 men and 84 women, mean age 65.9 years old (24.3-92.4) at primary THA and 72.9 years old (31.9-98.8) at revision. Revision surgery was performed a mean 7.1 years (± 7.1) after primary THA. The predictive risk factors for dislocation were: a 22.2mm diameter femoral head (risk × 2.4), a posterolateral approach (risk × 1.7), older age (risk × 1.1), an elevated rim liner for primary THA (risk × 6.6). The use of a dual mobility cup did not influence the rate of revision for dislocation (8.8%) compared to the use of a flat rim liner (9.1%).
  
  
  CONCLUSIONS
  The 10.4% rate of revision of THA for dislocation seems markedly lower than the results in the literature both for frequency and ranking. The use of elevated rim or constrained liners designed to decrease the risk of dislocation does not improve results compared to standard liners.
  
  
  METHODS
  Level IV, prospective prognostic study without a control group.
authors.affiliation: Université Lille Nord-de-France, 59000 Lille, France. j_girard_lille@yahoo.fr
authors.forename: J
authors.initials: J
authors.lastname: Girard
authors.forename: G
authors.initials: G
authors.lastname: Kern
authors.forename: H
authors.initials: H
authors.lastname: Migaud
authors.forename: C
authors.initials: C
authors.lastname: Delaunay
authors.forename: N
authors.initials: N
authors.lastname: Ramdane
authors.forename: M
authors.initials: M
authors.lastname: Hamadouche
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000379:methods; D016009:Chi-Square Distribution; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D005602:France; D006621:Hip Joint; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D015994:Incidence; D004204:Joint Dislocations / Q000453:epidemiology* / Q000209:etiology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011446:Prospective Studies; D011475:Prosthesis Failure; D016059:Range of Motion, Articular / Q000502:physiology; D012086:Reoperation / Q000706:statistics & numerical data; D018570:Risk Assessment; D017678:Sex Distribution; D018709:Statistics, Nonparametric; D016896:Treatment Outcome
keywords: Dislocation; Instability; Revision; Total hip arthroplasty