title: Is an algorithmic approach to the treatment of recurrent dislocation after THA effective?
abstract: BACKGROUND
  The indications for surgical techniques for treatment of recurrent hip dislocation after THA differ, and their rates of achievement of stability may not be similar.
  
  
  OBJECTIVE
  We (1) describe our indications for different approaches for recurrent dislocation, (2) outline an algorithmic approach to the management of recurrently dislocating hips after THA, and (3) determine the overall rate of restoration of stability via this algorithmic approach and for each of four procedures with our indications.
  
  
  METHODS
  We retrospectively reviewed 66 patients (69 hips) with revision THA for symptomatic recurrent dislocation from 1993 to 2008. We determined the rate of achievement of stability for the overall patient population and with each revision technique. Minimum followup was 2.8 years (mean, 7.8 years; range, 2.8-12.7 years).
  
  
  RESULTS
  Fifty-one of the 69 hips (74%) had no further dislocations while nine (13%) required two revisions and nine (13%) required three or more revisions. Ultimately, all of the 69 hips (100%) were stable at followup. Use of a large (36-mm-diameter) head, constrained cup, trochanteric advancement, correction of malposition, and a combination of techniques was effective in achieving stability in 67%, 68%, 86%, 91%, and 90% of cases, respectively.
  
  
  CONCLUSIONS
  Separating the treatment of patients based primarily on the presence or absence of (1) component malposition, (2) an intact abductor mechanism, and (3) implants accommodating a large-diameter femoral head, we were able to achieve hip stability with one operation in 74% of cases.
  
  
  METHODS
  Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
authors.affiliation: University of California San Francisco School of Medicine, San Francisco, CA, USA.
authors.forename: Ehsan
authors.initials: E
authors.lastname: Saadat
authors.forename: Glenn
authors.initials: G
authors.lastname: Diekmann
authors.forename: Steven
authors.initials: S
authors.lastname: Takemoto
authors.forename: Michael D
authors.initials: MD
authors.lastname: Ries
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000295:instrumentation; D003661:Decision Support Techniques; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D004204:Joint Dislocations / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D007593:Joint Instability / Q000209:etiology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D011859:Radiography; D016059:Range of Motion, Articular; D012008:Recurrence; D012086:Reoperation; D012189:Retrospective Studies; D012495:San Francisco; D013997:Time Factors; D016896:Treatment Outcome