title: A 2- to 7-Year Follow-Up of a Modular Iliac Screw Cup in Major Acetabular Defects: Clinical, Radiographic and Survivorship Analysis With Comparison to the Literature.
abstract: Inadequate acetabular bone stock is a major issue in total hip arthroplasty, and several treatment options are available. Stemmed cups have been used in this scenario with variable results. A novel modular polyaxial uncemented iliac screw cup (HERM-BS-Sansone cup-Citieffe s.r.l., Calderara di Reno, Bologna, Italy) has been recently introduced to overcome the drawbacks of stemmed cups. In this retrospective study, we report the results of this cup in patients with large acetabular bone defects at 2- to 7-year follow-up.
  
  
  
  We evaluated a consecutive series of 121 hips (118 revisions and 3 complex primary arthroplasties) treated with this novel cup at a mean follow-up of 46 months. Kaplan-Meier survival analysis was performed with implant revision for any reason as a primary end point. Further survival analysis was performed excluding septic failures. Clinical outcome was assessed with the Harris Hip Score.
  
  
  
  There had been 7 reoperations: 1 for aseptic loosening, 5 for deep infection, and 1 for recurrent dislocation. In 5 cases, the cup was removed; estimated survival rate at 5-year follow-up with implant removal for any reason was 95.6% (95% confidence interval = 91-99), and 98.3% (95% CI = 96-100) excluding those failed for infection. Mean Harris Hip Score at latest follow-up was 77 points (range, 44-95; standard deviation = 11.9).
  
  
  
  The present findings show the short-term efficacy of the iliac screw cup with respect to implant survival. A longer follow-up and a larger number of patients are necessary to confirm the encouraging preliminary results.
authors.affiliation: Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Cadossi
authors.affiliation: Ribeirão Preto Medical School (University of São Paulo), Ribeirão Preto, São Paulo, Brazil.
authors.forename: Flávio Luís
authors.initials: FL
authors.lastname: Garcia
authors.affiliation: Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Sambri
authors.affiliation: Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Isabella
authors.initials: I
authors.lastname: Andreoli
authors.affiliation: Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Dante
authors.initials: D
authors.lastname: Dallari
authors.affiliation: Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pignatti
mesh_terms: D000077:Acetabulum / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation* / Q000706:statistics & numerical data; D001863:Bone Screws; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis / Q000706:statistics & numerical data*; D006801:Humans; D004204:Joint Dislocations / Q000601:surgery; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011475:Prosthesis Failure; D011642:Publications; D011859:Radiography; D012086:Reoperation; D012189:Retrospective Studies; D016019:Survival Analysis
keywords: acetabulum; bone loss; hip joint; joint revision; total hip arthroplasty