title: A minimum 5-year follow-up of an oxidized zirconium femoral prosthesis used for total knee arthroplasty.
abstract: BACKGROUND
  Bearing surface wear remains a potential concern amongst younger patients undergoing total knee arthroplasty (TKA). Because of the potential for lower prosthetic wear rates, oxidized zirconium is a potentially attractive bearing surface for TKA in young, active patients. This material is also well suited for patients with suspected nickel sensitivities as it has no measurable nickel content, in contrast to standard femoral bearings made of cobalt-chromium alloys. Although in vitro testing on knee wear simulators has demonstrated favorable wear characteristics of oxidized zirconium compared to traditional cobalt-chrome bearings, in vivo clinical outcome data with this novel bearing surface are sparse.
  
  
  METHODS
  We retrospectively reviewed 109 consecutive TKAs in 82 patients at a minimum of five years postoperatively to determine prosthetic survivorship and to assess whether any adverse clinical consequences could be attributed to this bearing. Knees were evaluated with Knee Society scores, UCLA activity scores, clinical examinations, and radiographs. The mean age for this cohort was 58.7 years.
  
  
  RESULTS
  Survivorship free of bearing related complications was 100% at a minimum of five years post-surgery. There were no revisions for loosening, osteolysis, implant failure, or deep infection. There were no knees with radiographic failure, visible wear, loosening, or osteolysis.
  
  
  CONCLUSIONS
  Oxidized zirconium remains an attractive option for patients with nickel sensitivities and in those patients at risk for prosthetic wear due to young age or high activity levels.
authors.affiliation: Scripps Clinic, Division of Orthopaedic Surgery, La Jolla, CA, USA.
authors.forename: Jason K
authors.initials: JK
authors.lastname: Hofer
authors.affiliation: Scripps Clinic, Division of Orthopaedic Surgery, La Jolla, CA, USA. Electronic address: Ezzet.Kace@scrippshealth.org.
authors.forename: Kace A
authors.initials: KA
authors.lastname: Ezzet
mesh_terms: D000328:Adult; D000368:Aged; D001168:Arthritis / Q000601:surgery; D019645:Arthroplasty, Replacement, Knee; D017449:Dermatitis, Allergic Contact / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D009532:Nickel / Q000009:adverse effects; D063868:Patient Outcome Assessment; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D015040:Zirconium
chemical_list: D009532:Nickel; D015040:Zirconium
keywords: Ceramic knee; Knee replacement outcomes; Oxidized zirconium total knee arthroplasty; Total knee arthroplasty; Total knee arthroplasty outcomes