title: A comparison study of KOOS-PS and KOOS function and sport scores.
abstract: BACKGROUND
  The KOOS-PS represents a shortened version of the Knee Injury and Osteoarthritis Outcome Score (KOOS) Function and Sport scales. Previous investigations have not evaluated the KOOS-PS against performance measures or self-report measures composed of items that assess a broad spectrum of ability levels.
  
  
  OBJECTIVE
  The purpose of this study was to compare the construct validity of the KOOS Function and Sport subscales with a shorter version of the measure (KOOS-PS).
  
  
  METHODS
  Using a cross-sectional, observational design, consecutive consenting patients diagnosed with knee osteoarthritis were recruited at an assessment center visit to determine need for conservative or surgical management. Participants completed the Lower Extremity Functional Scale (LEFS), KOOS, Timed "Up & Go" Test, and Six-Minute Walk Test. A single function-sport score (KOOS FunSportsum) and the KOOS-PS were abstracted from the KOOS. Pearson correlation coefficients were compared between the reference standards' scores (performance measures and LEFS) and KOOS scores. KOOS-PSraw scores were compared with KOOS-PSRasch scores.
  
  
  RESULTS
  Three hundred seventy-seven patients with a mean age of 64.4 years (SD=10.5) participated. The correlation between performance reference standard and KOOS-PSRasch scores was significantly lower than with KOOS FunSportsum scores (mean difference in r=.08 [95% confidence interval=.03, .11], z=4.45, P1<.001). A similar finding was observed with the LEFS comparison.
  
  
  CONCLUSIONS
  The study sample did not consist of many patients with mild or severe functional status limitations.
  
  
  CONCLUSIONS
  For patients with knee osteoarthritis, the KOOS-PS appears too restricted in item content to provide a comprehensive estimate of lower extremity functional status level relative to the KOOS Function and Sport subscales. Pursuit of a computer-adapted test may be a productive direction for future inquiry.
authors.affiliation: P.W. Stratford, PT, MSc, Institute for Applied Sciences-School of Rehabilitation Science, McMaster University, 1400 Main St W, Hamilton, Ontario, Canada LS8 1C7. stratfor@mcmaster.ca.
authors.forename: Paul W
authors.initials: PW
authors.lastname: Stratford
authors.affiliation: D.M. Kennedy, PT, MSc, Holland Orthopaedic & Arthritic Centre-Rehabilitation, Toronto, Ontario, Canada.
authors.forename: Deborah M
authors.initials: DM
authors.lastname: Kennedy
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology* / Q000534:rehabilitation / Q000601:surgery; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000503:physiopathology* / Q000534:rehabilitation / Q000601:surgery; D017063:Outcome Assessment, Health Care; D018579:Patient Selection; D016059:Range of Motion, Articular / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology*; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013177:Sports / Q000502:physiology; D013647:Task Performance and Analysis