title: Short to Midterm Follow-Up of the Tritanium Primary Acetabular Component: A Cause for Concern.
abstract: Several acetabular components utilizing novel ultraporous metal substrates have been introduced over the past decade. Collectively by design, they have a lower modulus of elasticity to reduce stress shielding, a higher coefficient of friction to enhance interference fit, and ultraporous surfaces to enhance osseointegration. However, little literature exists regarding their clinical performance.
  
  
  
  This study compared the clinical and radiographic results of 109 hips in 95 patients using a Tritanium primary cup (Stryker, Mahwah, NJ) to an age, body mass index, and gender-matched cohort of 100 patients that received a contemporary cup (Stryker Trident PSL HA).
  
  
  
  At an average 4.24 + 1.49 years, implant survivorship of the Tritanium primary cup was 98.2%, with 2 cups revised for failure of osseointegration. One-year radiographs revealed radiolucent and radiosclerotic lines in 2 or more DeLee zones in 30.3% of cups and 3 zone involvement in 8.2%. These proportions increased (40.0% and 17.1%, respectively) at minimum 5-year follow-up. A comparison of 1 year and last follow-up radiographs revealed progression in 13.8%. Tritanium primary components with radiolucency in 2 or more zones exhibited significantly lower HHS at 2 years compared to all Trident peripheral self-locking (PSL) components (P < .0001) and Tritanium primary components with 1 zone or no radiolucency (P = .026). Scanning electron microscopy of a retrieved cup revealed local inflammatory reaction and no evidence of osseointegration.
  
  
  
  Despite adequate implant survivorship, over one third of Tritanium primary cups had 2 or more zone radiolucency at minimum 5-year follow-up with associated lower Harris hip scores.
authors.affiliation: Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, New York.
authors.forename: Alberto V
authors.initials: AV
authors.lastname: Carli
authors.affiliation: Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, New York.
authors.forename: Lucian C
authors.initials: LC
authors.lastname: Warth
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, New York.
authors.forename: Karen L
authors.initials: KL
authors.lastname: de Mesy Bentley
authors.affiliation: Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, New York.
authors.forename: Bryan J
authors.initials: BJ
authors.lastname: Nestor
mesh_terms: D000077:Acetabulum / Q000601:surgery; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D005260:Female; D005500:Follow-Up Studies; D017276:Friction; D006621:Hip Joint / Q000000981:diagnostic imaging; D006622:Hip Prosthesis / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D016348:Osseointegration; D011859:Radiography; D014025:Titanium
chemical_list: D014025:Titanium
keywords: Trabecular Metal; acetabular fixation; osseointegration failure; primary hip arthroplasty; ultraporous metal substrates