title: Five year survival analysis of an oxidised zirconium total knee arthroplasty.
abstract: BACKGROUND
  Zirconium total knee arthroplasties theoretically have a low incidence of failure as they are low friction, hard wearing and hypoallergenic. We report the five year survival of 213 Profix zirconium total knee arthroplasties with a conforming all polyethylene tibial component.
  
  
  METHODS
  Data was collected prospectively and multiple strict end points were used. SF12 and WOMAC scores were recorded pre-operatively, at three months, at twelve months, at 3 years and at 5 years.
  
  
  RESULTS
  Eight patients died and six were "lost to follow-up". The remaining 199 knees were followed up for five years. The mean WOMAC score improved from 56 to 35 and the mean SF12 physical component score improved from 28 to 34. The five year survival for failure due to implant related reasons was 99.5% (95% CI 97.4-100). This was due to one tibial component becoming loose aseptically in year zero.
  
  
  CONCLUSIONS
  Our results demonstrate that the Profix zirconium total knee arthroplasty has a low medium term failure rate comparable to the best implants. Further research is needed to establish if the beneficial properties of zirconium improve long term implant survival.
authors.affiliation: The Lower Limb Arthroplasty Unit, The Department of Orthopaedics, The Royal Liverpool and Broadgreen University Hospitals NHS Trust, Liverpool, L7 8XP, UK. Electronic address: ph.holland@gmail.com.
authors.forename: Philip
authors.initials: P
authors.lastname: Holland
authors.forename: Alasdair J A
authors.initials: AJ
authors.lastname: Santini
authors.forename: John S
authors.initials: JS
authors.lastname: Davidson
authors.forename: Jill A
authors.initials: JA
authors.lastname: Pope
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000379:methods*; D019245:Compressive Strength; D016208:Databases, Factual; D005260:Female; D006801:Humans; D007720:Knee Prosthesis; D008422:Materials Testing; D008875:Middle Aged; D020959:Polyethylene; D011379:Prognosis; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure / Q000639:trends*; D016059:Range of Motion, Articular / Q000502:physiology; D018570:Risk Assessment; D013997:Time Factors; D016896:Treatment Outcome; D015040:Zirconium
chemical_list: D020959:Polyethylene; D015040:Zirconium