title: Dual-mobility implants prevent hip dislocation following hip revision in obese patients.
abstract: Revision total hip arthroplasty (THA) is associated with increased rates of dislocation in obese patients. It is not known whether dual-mobility implants decrease dislocation in these patients with obesity.
  
  
  
  We retrospectively reviewed two groups of revision THAs to compare the dislocation rate between 32 obese patients (BMI >30 kg/m2) with standard cups, and 35 obese patients (BMI >30 kg/m2) with dual-mobility cups. All patients received the same implants except for diameter head (32-mm head with standard cups and 28-mm head with dual mobility) and had the same cemented stem that was not changed at revision. The patients were followed at routine intervals and were specifically queried about dislocation. The two groups were similar in terms of age, gender, causes of revision and follow-up since the primary arthroplasty.
  
  
  
  With standard liners, more hips in obese patients dislocated than did hips in obese patients who received dual-mobility implants. The number of dislocations in standard hips was at one year follow-up 15.6 % (5 of 32) compared with 0 % in dual-mobility hips and was at five year follow-up 21.8 % (7 of 32) compared with 2.8 % (1 of 35). After a mean follow-up of seven years no cases of loosening were found. Five patients in the obese group with a standard liner underwent re-revision surgery, the additional re-operations being necessary to treat recurrent postoperative dislocation.
  
  
  
  Obese patients should be counselled about the important risk of dislocation that occurs with standard liners after revision THA. Dual-mobility liners in these patients with hip revision is an efficient technique to prevent post-operative hip dislocation.
authors.affiliation: Department of Orthopaedic Surgery, University Paris East (UPEC), Hôpital Henri Mondor, 94010, Creteil, France. philippe.hernigou@wanadoo.fr.
authors.forename: Philippe
authors.initials: P
authors.lastname: Hernigou
authors.affiliation: Department of Orthopedic Surgery, University Paris West, Hôpital Antoine-Béclère, 92140, Clamart, France.
authors.forename: Jean Charles
authors.initials: JC
authors.lastname: Auregan
authors.affiliation: Department of Orthopaedic Surgery, University Paris East (UPEC), Hôpital Henri Mondor, 94010, Creteil, France.
authors.forename: Damien
authors.initials: D
authors.lastname: Potage
authors.affiliation: Department of Orthopaedic Surgery, University Paris East (UPEC), Hôpital Henri Mondor, 94010, Creteil, France.
authors.forename: François
authors.initials: F
authors.lastname: Roubineau
authors.affiliation: Department of Orthopaedic Surgery, University Paris East (UPEC), Hôpital Henri Mondor, 94010, Creteil, France.
authors.forename: Charles Henri
authors.initials: CH
authors.lastname: Flouzat Lachaniette
authors.affiliation: Department of Orthopaedic Surgery, University Paris East (UPEC), Hôpital Henri Mondor, 94010, Creteil, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Dubory
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D006617:Hip Dislocation / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000601:surgery; D011474:Prosthesis Design; D012086:Reoperation / Q000009:adverse effects*; D012189:Retrospective Studies; D013997:Time Factors
keywords: Dislocation; Dual mobility; Hip revision; Obesity