title: Midterm results of surgical hip dislocation for the treatment of femoroacetabular impingement.
abstract: BACKGROUND
  Surgical treatment of femoroacetabular impingement (FAI) includes both open and arthroscopic procedures. Encouraging results have been reported for the majority of patients after surgical hip dislocation; however, most of these reports were short term and included only small cohorts.
  
  
  OBJECTIVE
  To determine the results of surgical hip dislocation in a large cohort of FAI patients at a midterm follow-up.
  
  
  METHODS
  Case series; Level of evidence, 4.
  
  
  METHODS
  A retrospective study including 185 consecutive patients (mean age, 30 years; 40% female) with 233 hips treated was conducted. We determined clinical outcomes in terms of range of motion and analyzed radiographs for several criteria including the alpha angle preoperatively and at 1 year postoperatively. At latest follow-up, on average 61 months postoperatively, patient satisfaction, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Hip Outcome Score, SF-12, and University of California, Los Angeles (UCLA) activity scale scores were determined. All revisions and conversions to total hip arthroplasty (THA) were recorded.
  
  
  RESULTS
  Both hip flexion and internal rotation improved from preoperatively to postoperatively. Alpha angles decreased from 65.1° ± 14.2° to 42.4° ± 4.9°. At 5 years, 82% of the patients were satisfied or very satisfied with the results of surgery, and 81% would undergo the same surgery again. There were 83% who rated their overall hip function as normal or nearly normal. Mean scores for the WOMAC pain, stiffness, and function subscales were 10.3 ± 15.8, 15.9 ± 17.4, and 9.6 ± 13.0 points; for Hip Outcome Score activities of daily living and sport subscales were 89.0 ± 13.1 and 75.6 ± 23.0 points; and for the SF-12 Physical Component Scale and Mental Component Scale were 47.4 ± 6.3 and 52.3 ± 7.4 points, respectively. The mean UCLA activity level was 7.7 ± 1.9. Conversion to THA was performed in 7 hips (3%). Seven hips (3%) underwent other major revisions, and 11 (4.7%) underwent minor revisions. Female patients had a significantly increased risk for conversion to THA (odds ratio, 13.3; 95% confidence interval [CI], 1.3-92.6) and major revision (odds ratio, 19.2; 95% CI, 2.4-152.9). The mean body mass index was significantly lower in those patients who underwent conversion to THA. The need for microfracture because of residual full-thickness cartilage defects after rim trimming was a significant (P = .04) predictor of subjective dissatisfaction.
  
  
  CONCLUSIONS
  This study demonstrates that surgical hip dislocation is a successful procedure for the treatment of FAI. A majority of patients were satisfied with the results of surgery at a midterm follow-up. Older and slim female patients were at an increased risk for a less successful outcome in terms of conversion to THA and revision surgery.
authors.affiliation: Department of Orthopaedic Surgery, Schulthess Clinic, Lengghalde 2, 8008 Zurich, Switzerland. florian.naal@gmail.com
authors.forename: Florian D
authors.initials: FD
authors.lastname: Naal
authors.forename: Hermes H
authors.initials: HH
authors.lastname: Miozzari
authors.forename: Michael
authors.initials: M
authors.lastname: Schär
authors.forename: Tobias
authors.initials: T
authors.lastname: Hesper
authors.forename: Hubert P
authors.initials: HP
authors.lastname: Nötzli
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D019644:Arthroplasty, Replacement, Hip; D005260:Female; D057925:Femoracetabular Impingement / Q000175:diagnosis / Q000601:surgery*; D005500:Follow-Up Studies; D006615:Hip / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017060:Patient Satisfaction; D011182:Postoperative Care; D011183:Postoperative Complications; D011859:Radiography; D016059:Range of Motion, Articular; D012086:Reoperation; D012189:Retrospective Studies; D012399:Rotation; D016896:Treatment Outcome; D055815:Young Adult