title: Risk factors for early dislocation after total hip arthroplasty: a matched case-control study.
abstract: OBJECTIVE
  To evaluate risk factors for early dislocation after primary total hip arthroplasty (THA).
  
  
  METHODS
  Records of 175 cases with dislocation during hospitalisation after THA and 651 controls without dislocation were reviewed. Cases and controls were matched for age, gender, body mass index classification, primary diagnosis, cup design, hospital, and year of intervention. Version and inclination of the acetabular component and version of the femoral component were assessed intra- and post-operatively. Various risk factors were analysed, including surgical approach, cup positioning, combined cup and stem positioning, and femoral head size.
  
  
  RESULTS
  The posterior approach was 6 fold more prone to dislocation (odds ratio [OR]=6.3, p<0.018) than the anterolateral or straight lateral approach. With regard to combined cup and stem positioning, the acceptable position was at significantly higher risk of dislocation than the ideal position (OR=2.59, p=0.033). Larger femoral head sizes were associated with significantly lower risk of dislocation (OR=0.84, p=0.02).
  
  
  CONCLUSIONS
  Surgical approach, combined cup and stem positioning, and femoral head size were significant risk factors for dislocation during hospitalisation.
authors.affiliation: Department of Orthopaedic Surgery, Inselspital Berne, University of Berne, Switzerland. marcel.dudda@rub.de
authors.forename: Marcel
authors.initials: M
authors.lastname: Dudda
authors.forename: A
authors.initials: A
authors.lastname: Gueleryuez
authors.forename: E
authors.initials: E
authors.lastname: Gautier
authors.forename: A
authors.initials: A
authors.lastname: Busato
authors.forename: C
authors.initials: C
authors.lastname: Roeder
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D015992:Body Mass Index; D005060:Europe / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006617:Hip Dislocation / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology*; D006801:Humans; D015994:Incidence; D008297:Male; D016017:Odds Ratio; D015207:Osteoarthritis, Hip / Q000601:surgery; D011183:Postoperative Complications; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors; D017211:Treatment Failure