title: Development of the Knee OA Pre-Screening Questionnaire.
abstract: OBJECTIVE
  Self-report questionnaires are still considered to be a useful instrument for disease screening and for epidemiological studies. Few questionnaires have been developed for the purpose of screening for knee osteoarthritis (KOA). The aim of this study was to develop a KOA screening tool that is useful for health and exercise professionals who do not have access to advanced and costly diagnostic instruments.
  
  
  METHODS
  This study comprised five steps: content validity, reliability, criterion validity, construct validity and responsiveness. Internal consistency was verified using Cronbach's alpha and the intraclass correlation coefficient (ICC). Reproducibility was analyzed using the ICC (1 week). Criterion validity was assessed by comparing the Knee OA Pre-Screening Questionnaire (KOPS) score with the Short Form (SF)-12, the Knee Injury and Osteoarthritis Outcome Scores questionnaire and the 6 min walk test. Construct validity was verified using the receiver operating characteristic (ROC) curve (American College of Rheumatology clinical criteria and X-ray). Responsiveness was analyzed over 3 months of an aquatic exercise program using the pooled effect size.
  
  
  RESULTS
  The overall KOPS score yielded a Cronbach's alpha of 0.747 and an ICC of 0.646. KOPS was considered reproducible (ICC: 0.895-0.992; Cronbach's alpha: 0.894-0.979). The ROC curve revealed a sensitivity of 86.96 and a specificity of 75.82. The KOPS demonstrated medium responsiveness in terms of the total score and the pain and symptoms components.
  
  
  CONCLUSIONS
  The KOPS questionnaire is valid for the purposes for which it was created, and its translation into English should be considered.
authors.affiliation: Univ Lisboa, Fac Motricidade Humana, CIPER, LBMF, P-1499-002, Lisbon, Portugal.
authors.forename: Flavia
authors.initials: F
authors.lastname: Yázigi
authors.affiliation: Univ Lisboa, Fac Motricidade Humana, CIPER, LBMF, P-1499-002, Lisbon, Portugal.
authors.forename: Filomena
authors.initials: F
authors.lastname: Carnide
authors.affiliation: Univ Lisboa, Fac Motricidade Humana, CIPER, LBMF, P-1499-002, Lisbon, Portugal.
authors.forename: Margarida
authors.initials: M
authors.lastname: Espanha
authors.affiliation: Portuguese Institute of Rheumatology, Lisbon, Portugal.
authors.forename: Miguel
authors.initials: M
authors.lastname: Sousa
mesh_terms: D000328:Adult; D019540:Area Under Curve; D005080:Exercise Test; D005081:Exercise Therapy; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D007802:Language; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy; D010147:Pain Measurement; D011174:Portugal; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D057566:Self Report; D013997:Time Factors; D016896:Treatment Outcome; D016138:Walking
keywords: construction; knee osteoarthritis; questionnaire; screening; validation