title: What is the benefit of introducing new hip and knee prostheses?
abstract: BACKGROUND
  New joint replacement prostheses are being continually introduced into the market. The underlying purpose of the introduction of new devices is to improve patient outcomes. This study was undertaken to determine how many new prostheses were associated with improved patient outcomes.
  
  
  BACKGROUND
  Data were obtained from a comprehensive national database. Outcome analysis was performed on all new hip and knee prostheses introduced into the market between January 1, 2003, and December 31, 2007, and used on at least 100 occasions. The findings were compared with the combined results of the three best performing established hip and knee prostheses with a minimum duration of follow-up of five years. The principal outcome measures were the rate of revision per observed component years and the time to first revision, with use of Kaplan-Meier estimates of implant survivorship.
  
  
  RESULTS
  Most prostheses introduced into the market during the study period were used on fewer than 100 occasions. Analysis of those that had been used in a sufficient number of procedures showed that 27% (nine of thirty-three) of the hip replacements and 29% (eight of twenty-eight) of the knee replacements had a significantly higher rate of revision than the established prostheses. None of the newer prostheses had a lower rate of revision than the established prostheses.
  
  
  CONCLUSIONS
  This study indicates that there was no benefit to the introduction of new prostheses into this national market during the five-year study period. Importantly, 30% of the new prostheses were associated with a significantly worse outcome compared with the prostheses with a minimal duration of follow-up of five years.
authors.affiliation: Discipline of Public Health, University of Adelaide, MDP DX650, 511 Australia SA 5005.
authors.forename: Rajan
authors.initials: R
authors.lastname: Anand
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Graves
authors.forename: Richard N
authors.initials: RN
authors.lastname: de Steiger
authors.forename: David C
authors.initials: DC
authors.lastname: Davidson
authors.forename: Philip
authors.initials: P
authors.lastname: Ryan
authors.forename: Lisa N
authors.initials: LN
authors.lastname: Miller
authors.forename: Kara
authors.initials: K
authors.lastname: Cashman
mesh_terms: D001315:Australia; D003257:Consumer Product Safety; D019317:Evidence-Based Medicine / Q000706:statistics & numerical data; D005500:Follow-Up Studies; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D007720:Knee Prosthesis / Q000009:adverse effects*; D011358:Product Surveillance, Postmarketing / Q000706:statistics & numerical data; D016016:Proportional Hazards Models; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012042:Registries / Q000706:statistics & numerical data; D012086:Reoperation / Q000706:statistics & numerical data; D016019:Survival Analysis