title: Survivorship of monoblock trabecular metal cups in primary THA : midterm results.
abstract: Monoblock trabecular metal cups are made of a novel porous material intended to enhance ingrowth and improve fixation. We prospectively followed 223 consecutive patients with 245 trabecular metal acetabular cups implanted during primary total hip arthroplasties to determine the overall survivorship of the implant, and any association of survivorship to primary diagnosis and age, and to determine the fate of polar gaps and cysts. Minimum followup was 36 months (mean, 60 months; range, 36-112 months). Patients were assessed with the Harris Hip score and the Oxford questionnaire and radiographically with standardized serial radiographs. At last followup, all cups were radiographically stable with no evidence of migration or progressive radiolucencies. The survivorship with reoperation as the end point was estimated at 98.75% with a 95% confidence interval. Three reoperations occurred during the first 36 months. The Harris hip score increased from 48 to 94 and the Oxford score was 16.4 at the last examination. We observed no difference in terms of survivorship among patients with osteoarthritis, osteonecrosis, or hip dysplasia. Seven of 14 (50%) osteoarthritis cysts and 10 of 33 (33.3%) polar gaps detected on postoperative radiographs decreased or filled, whereas none of the remainder deteriorated with time. Our midterm results suggest this implant may enhance fixation, but long-term followup is needed to confirm our findings.
  
  
  METHODS
  Level IV Therapeutic study.
authors.affiliation: Orthopaedic Department, University of Thessalia, Larissa, Greece.
authors.forename: Konstantinos N
authors.initials: KN
authors.lastname: Malizos
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Bargiotas
authors.forename: Loukia
authors.initials: L
authors.lastname: Papatheodorou
authors.forename: Michael
authors.initials: M
authors.lastname: Hantes
authors.forename: Theofilos
authors.initials: T
authors.lastname: Karachalios
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000601:surgery*; D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D005260:Female; D006305:Health Status Indicators; D006618:Hip Dislocation, Congenital / Q000601:surgery; D006621:Hip Joint; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000601:surgery; D010020:Osteonecrosis / Q000601:surgery; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D016059:Range of Motion, Articular; D012086:Reoperation; D011795:Surveys and Questionnaires; D013635:Tantalum
chemical_list: D013635:Tantalum