title: Timing of total joint replacement affects clinical outcomes among patients with osteoarthritis of the hip or knee.
abstract: OBJECTIVE
  To determine the predictors of outcome in patients with osteoarthritis 2 years after receiving total hip or knee replacement.
  
  
  METHODS
  A prospective cohort study of 222 osteoarthritis patients undergoing total hip or knee replacement in Boston and Montreal was done. Their postoperative outcomes at 6 months were previously reported. This followup reports on the outcomes after 2 years among the 165 patients (74%) who remained. The subjects were divided into 2 groups according to the median value of their preoperative Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) function score. The Short Form 36-item physical function subscale and the WOMAC pain and function subscale scores were collected at baseline and at 3, 6, and 24 months postoperatively. Clinical outcomes were analyzed at 2 years, using descriptive and multiple regression analyses.
  
  
  RESULTS
  Improvements in pain and function at 2 years were similar to those observed at 6 months. Those subjects with the worst function and pain at the time of surgery (baseline) had comparatively worse function 2 years after surgery.
  
  
  CONCLUSIONS
  In this comparison, the poor outcomes observed at 6 months following total joint replacement in patients with worse baseline functional status persisted after 2 years. Although there are no validated indications for when a patient should optimally have total joint replacement, these data suggest that timing of surgery may be more important than previously realized and, specifically, that performing surgery earlier in the course of functional decline may be associated with better outcome.
authors.affiliation: University of Toronto, Toronto, Ontario, Canada. paul.fortin@uhn.on.ca
authors.forename: Paul R
authors.initials: PR
authors.lastname: Fortin
authors.forename: John R
authors.initials: JR
authors.lastname: Penrod
authors.forename: Ann E
authors.initials: AE
authors.lastname: Clarke
authors.forename: Yvan
authors.initials: Y
authors.lastname: St-Pierre
authors.forename: Lawrence
authors.initials: L
authors.lastname: Joseph
authors.forename: Patrick
authors.initials: P
authors.lastname: Bélisle
authors.forename: Matthew H
authors.initials: MH
authors.lastname: Liang
authors.forename: Diane
authors.initials: D
authors.lastname: Ferland
authors.forename: Charlotte B
authors.initials: CB
authors.lastname: Phillips
authors.forename: Nizar
authors.initials: N
authors.lastname: Mahomed
authors.forename: Michael
authors.initials: M
authors.lastname: Tanzer
authors.forename: Clement
authors.initials: C
authors.lastname: Sledge
authors.forename: Anne H
authors.initials: AH
authors.lastname: Fossel
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Katz
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D019645:Arthroplasty, Replacement, Knee; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000503:physiopathology / Q000601:surgery*; D011184:Postoperative Period; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome