title: Two-year radiologic assessment of the Trident Peripheral Self-Locking cup using EBRA.
abstract: We performed a radiologic assessment of the Trident Peripheral Self-Locking cup 2 years after implantation to assess early migration behaviour and to establish if incomplete postoperative seating correlated with early instability. A retrospective analysis of 30 cases was performed using EBRA. No cups had acetabular screws. Average total migration was 1.5 mm (range 0.1 to 5.9 mm). Seventeen showed total migration >1 mm and 7 of these showed further migration >2 mm (range 2.3 to 5.9 mm). Twenty cups demonstrated incomplete seating on initial post-operative radiographs (mean 1.4 mm, range 0.3 to 3.0). No relationship between incomplete seating and migration was identified (p = 0.86). The majority of gaps consolidated at differing times within the 2 year period. Oxford Hip scores showed significant improvement after surgery (p = 0.001) and this was independent of migration (p = 0.76). At 5 years there were no revisions for aseptic loosening.
  
  
  CONCLUSIONS
  The majority of the cups demonstrated early radiographic instability, and this was not related to incomplete seating. Five year functional outcome appears good and independent of migration and initial seating.
authors.affiliation: Department of Orthopaedics, Golden Jubilee National Hospital, Agamemnon Street, Clydebank, Dunbartonshire, UK.
authors.forename: Perrico
authors.initials: P
authors.lastname: Nunag
authors.forename: Angela H
authors.initials: AH
authors.lastname: Deakin
authors.forename: Ezekiel
authors.initials: E
authors.lastname: Oburu
authors.forename: Martin
authors.initials: M
authors.lastname: Sarungi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods; D004185:Disability Evaluation; D019544:Equipment Failure Analysis / Q000379:methods*; D005260:Female; D006304:Health Status; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D010149:Postoperative Pain / Q000209:etiology / Q000503:physiopathology; D011474:Prosthesis Design; D011475:Prosthesis Failure; D017755:Prosthesis Fitting; D011788:Quality of Life; D011859:Radiography; D012189:Retrospective Studies; D012720:Severity of Illness Index