Persian translation and validation of the Kujala Patellofemoral Scale in patients with patellofemoral pain syndrome

Disabil Rehabil. 2012;34(26):2259-63. doi: 10.3109/09638288.2012.683480. Epub 2012 May 27.


Purpose: To culturally translate and validate the Persian version of Kujala Patellofemoral Scale (KPS) and evaluate the test-retest reliability, internal consistency, construct validity and ceiling or floor effects of this instrument in patients with patellofemoral pain syndrome (PFPS).

Method: After standard forward and backward translations, 100 patients with PFPS completed the Persian versions of the KPS and Short-Form 36 Health Survey (SF-36) in the first visit. With time interval of 2-3 days after the first visit, 47 patients filled out the KPS in the second visit. Test-retest reliability and internal consistency were assessed using intraclass correlation coefficient (ICC(2,1)) with 95% confidence interval (95% CI) and Cronbach's α coefficient, respectively. The Spearman's rank correlation (r(s)) was used to assess the correlations between the Persian KPS and SF-36 subscales.

Results: The acceptable level of ICC >0.70 (ICC = 0.96, 95% CI = 0.93-0.98) and Cronbach's α coefficient >0.70 (α = 0.81) was obtained for the Persian KPS. There were low to moderate correlations (r(s) = 0.25-0.60, p < .01) between the Persian KPS and Persian SF-36 subscales of mental and physical health components. However, correlations between the Persian KPS and SF-36 physical components were higher than correlations between the Persian KPS and SF-36 mental components. No ceiling and floor effects were seen for the Persian KPS.

Conclusions: The Persian version of KPS is a reliable and valid outcome measure of disability and seems to be a suitable instrument for use in clinical practice of Iranian patients with chronic PFPS.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Adult
  • Cross-Cultural Comparison
  • Disability Evaluation
  • Female
  • Health Status Indicators
  • Health Surveys
  • Humans
  • Iran
  • Language
  • Male
  • Middle Aged
  • Outcome Assessment, Health Care
  • Pain Measurement
  • Patellofemoral Joint / physiopathology
  • Patellofemoral Pain Syndrome / physiopathology*
  • Patellofemoral Pain Syndrome / psychology
  • Psychometrics / methods
  • Psychometrics / standards*
  • Quality of Life
  • Reproducibility of Results
  • Surveys and Questionnaires / standards*
  • Translations*