title: Validity and reliability of Thai version of the International Knee Documentation Committee Subjective Knee Form.
abstract: BACKGROUND
  Self-administered questionnaires have become an important aspect for clinical outcome assessment of knee-related surgery. The International Knee Documentation Committee (IKDC) Subjective Knee Form is a knee-specific questionnaire that is widely used and translated to many languages. The purposes of the present study were: (1) to translate the questionnaire into Thai; and (2) to assess the validity and reliability of the Thai version of the International Knee Documentation Committee (IKDC) Subjective Knee Form.
  
  
  METHODS
  The IKDC Subjective Knee Form was translated into Thai using forward-backward translation protocol. Afterward, reliability and validity were tested The responses of 55 consecutive patients on two questionnaires, the Thai IKDC Subjective Knee Form and the Short Form-36, were used. The validity was tested by correlating the scores from both questionnaires. The reliability was adopted by measuring the test-retest reliability and internal consistency.
  
  
  RESULTS
  The Thai IKDC Subjective Knee Form showed good correlations with the physical functioning and bodily pain domains of the SF-36 (Pearson's correlation coefficient = 0.75 and 0.76 respectively). The reliability proved excellent with an intra-class correlation coefficient of 0.92 for test-retest. The internal consistency was strong (Cronbach alpha = 0.92).
  
  
  CONCLUSIONS
  The Thai version of IKDC Subjective Knee Form showed good value to retain the characteristic of the original version. In addition, it was a reliable evaluation instrument for patients with knee-related problems.
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand. siplw@mahidol.ac.th
authors.forename: Pisit
authors.initials: P
authors.lastname: Lertwanich
authors.forename: Teeranit
authors.initials: T
authors.lastname: Praphruetkit
authors.forename: Ekavit
authors.initials: E
authors.lastname: Keyurapan
authors.forename: Chanin
authors.initials: C
authors.lastname: Lamsam
authors.forename: Teerawat
authors.initials: T
authors.lastname: Kulthanan
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006305:Health Status Indicators; D006306:Health Surveys; D006801:Humans; D007592:Joint Diseases / Q000523:psychology / Q000601:surgery*; D007717:Knee / Q000601:surgery*; D007718:Knee Injuries / Q000523:psychology / Q000601:surgery*; D007802:Language; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures; D011788:Quality of Life; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D013785:Thailand