title: Comparison of the responsiveness of the SF-36, the Oxford Knee Score, and the Knee Society Clinical Rating System in patients undergoing total knee replacement.
abstract: OBJECTIVE
  To compare the responsiveness of the Knee Society (KS) Clinical Rating System, the general health status measure Short Form 36 (SF-36), and both the raw and Rasch-based scores of the condition-specific Oxford Knee Score (OKS) in patients undergoing total knee replacement (TKR) METHODS: Data were prospectively collected as part of routine care from adult patients who underwent TKR between 2001 and 2006. OKS data fit the Rasch partial credit model after removing items regarding limping and kneeling. Responsiveness was assessed using effect size (ES), standardised response mean (SRM), and relative validity (RV).
  
  
  RESULTS
  Among 702 patients with complete data at baseline and two follow-ups, the pain subscale of the KS (KS-P), raw-OKS, and Rasch-OKS consistently had higher levels of responsiveness than all eight SF-36 and the other KS subscales. At 6-month follow-up, Rasch-OKS had the largest ES and KS-P had the largest SRM (2.7 and 2.0, respectively). When compared to raw-OKS, the RVs of KS-P, Rasch-OKS, SF-36 bodily pain, and SF-36 physical functioning were 1.1, 0.66, 0.49, and 0.36, respectively. A similar ordering of responsiveness was observed at 24-month follow-up.
  
  
  CONCLUSIONS
  The OKS and KS-P are more responsive than most SF-36 subscales in TKR patients. Raw-OKS and Rasch-OKS have comparable responsiveness. Different responsiveness indices may give different results.
authors: Department of Pharmacy, Faculty of Science, National University of Singapore, Block S4, 18 Science Drive 4, Singapore, 117543, Singapore, phakyn@nus.edu.sg.
authors: Yu
authors: Y
authors: Ko
authors: Ngai-Nung
authors: NN
authors: Lo
authors: Seng-Jin
authors: SJ
authors: Yeo
authors: Kuang-Ying
authors: KY
authors: Yang
authors: William
authors: W
authors: Yeo
authors: Hwei-Chi
authors: HC
authors: Chong
authors: Julian
authors: J
authors: Thumboo
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000534:rehabilitation*; D005260:Female; D006304:Health Status; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000503:physiopathology* / Q000601:surgery; D010147:Pain Measurement / Q000379:methods; D011446:Prospective Studies; D011788:Quality of Life; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires