title: Comparison of dual-mobility cup and unipolar cup for prevention of dislocation after revision total hip arthroplasty.
abstract: Background and purpose - Revision total hip arthroplasty (THA) is associated with higher dislocation rates than primary THA. We compared the risk of dislocation within 6 months and all-cause re-revision during the whole study period using either the dual-mobility cup or the unipolar cup. Methods - We used a prospective hospital registry-based cohort including all total and cup-only revision THAs performed between 2003 and 2013. The cups used were either dual-mobility or unipolar; the choice was made according to the preference of the surgeon. 316 revision THAs were included. The mean age of the cohort was 69 (25-98) years and 160 THAs (51%) were performed in women. The dual-mobility group (group 1) included 150 THAs (48%) and the mean length of follow-up was 31 (0-128) months. The unipolar group (group 2) included 166 THAs (53%) and the mean length of follow-up was 52 (0-136) months. Results - The incidence of dislocation within 6 months was significantly lower with the dual-mobility cup than with the unipolar cup (2.7% vs. 7.8%). The unadjusted risk ratio (RR) was 0.34 (95% CI: 0.11-1.02) and the adjusted RR was 0.28 (95% CI: 0.09-0.87). The number of patients needed to treat with a dual-mobility cup in order to prevent 1 case of dislocation was 19. The unadjusted incidence rate ratio for all-cause re-revision in the dual-mobility group compared to the unipolar group was 0.6 (95% CI: 0.3-1.4). Interpretation - Use of a dual-mobility rather than a unipolar cup in revision THA reduced the risk of dislocation within 6 months.
authors.affiliation: a Division of Orthopaedics and Trauma Surgery.
authors.forename: Amanda Inez
authors.initials: AI
authors.lastname: Gonzalez
authors.affiliation: a Division of Orthopaedics and Trauma Surgery.
authors.forename: Placido
authors.initials: P
authors.lastname: Bartolone
authors.affiliation: a Division of Orthopaedics and Trauma Surgery.
authors.forename: Anne
authors.initials: A
authors.lastname: Lubbeke
authors.affiliation: b Division of Epidemiology , Geneva University Hospitals , Switzerland.
authors.forename: Elise
authors.initials: E
authors.lastname: Dupuis Lozeron
authors.affiliation: a Division of Orthopaedics and Trauma Surgery.
authors.forename: Robin
authors.initials: R
authors.lastname: Peter
authors.affiliation: a Division of Orthopaedics and Trauma Surgery.
authors.forename: Pierre
authors.initials: P
authors.lastname: Hoffmeyer
authors.affiliation: a Division of Orthopaedics and Trauma Surgery.
authors.forename: Panayiotis
authors.initials: P
authors.lastname: Christofilopoulos
mesh_terms: D000077:Acetabulum / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006617:Hip Dislocation / Q000453:epidemiology / Q000517:prevention & control*; D006622:Hip Prosthesis; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation; D013557:Switzerland / Q000453:epidemiology; D013997:Time Factors