title: Development and validation of a new evaluation system for patients with a floor-based lifestyle: the Korean knee score.
abstract: BACKGROUND
  Patients' perspectives on functioning and health have been increasingly recognized as a crucial aspect of health care, leading to the use of patient-reported instruments for outcome assessment. However, available instruments for total knee arthroplasty do not reflect the floor-based lifestyle with high knee flexion of eastern Asia.
  
  
  OBJECTIVE
  We therefore (1) describe a novel patient-generated knee evaluation instrument, the Korean knee score (KKS), to reflect floor-based lifestyles with high knee flexion that included questions regarding health-related quality of life; (2) determined the reliability of the questionnaire; and (3) performed limited validation studies.
  
  
  METHODS
  The KKS was developed by a committee of 10 experts from 10 institutes nationwide. The development procedure comprised a development phase for generation of the questionnaire and a testing phase for assessment of measurement properties: reliability, validity, and responsiveness. A total of 634 patients participated in this test survey.
  
  
  RESULTS
  The KKS exhibited an intraclass correlation coefficient of 0.931 and internal consistency (Cronbach's α = 0.973). The absence of a ceiling or floor effect suggested content validity. The correlation coefficient with Knee Society score (knee score, function score) and Oxford knee score was 0.599, 0.690, and 0.871, respectively, suggesting construct validity. Correlation with concurrent measures of physical function from the SF-36 ranged from 0.549 to 0.719 and those of mental function from 0.407 to 0.428. Responsiveness was evident with a standardized response mean of 0.74.
  
  
  CONCLUSIONS
  The KKS is a reliable and responsive instrument for assessing osteoarthritis. The limited validation studies suggest it is an appropriate evaluation instrument for patients with osteoarthritis and a floor-based lifestyle.
authors.affiliation: Department of Orthopedic Surgery, Seoul Paik Hospital, Inje University, Seoul, Korea.
authors.forename: Jin Goo
authors.initials: JG
authors.lastname: Kim
authors.forename: Jeong Ku
authors.initials: JK
authors.lastname: Ha
authors.forename: Seung Beom
authors.initials: SB
authors.lastname: Han
authors.forename: Tae Kyun
authors.initials: TK
authors.lastname: Kim
authors.forename: Myung Chul
authors.initials: MC
authors.lastname: Lee
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D044466:Asian People; D001696:Biomechanical Phenomena; D003466:Cultural Characteristics; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008019:Life Style / Q000208:ethnology*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D020370:Osteoarthritis, Knee / Q000175:diagnosis* / Q000208:ethnology / Q000503:physiopathology; D011237:Predictive Value of Tests; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D056910:Republic of Korea / Q000453:epidemiology; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires