Translation and cross-cultural adaptation of the Brazilian version of the International Knee Documentation Committee Subjective Knee Form: validity and reproducibility.
BACKGROUND
The perception of improvement by a patient has assumed a central role in functional evaluation after a variety of knee problems. One of the instruments most used in clinical research is the International Knee Documentation Committee (IKDC) Subjective Knee Form because its psychometric properties are considered to be excellent. Nonetheless, this questionnaire was originally developed for use in the English language. Therefore, to use this questionnaire in the Brazilian population, it is essential to translate and validate it.


OBJECTIVE
The aim of this study was to translate the IKDC Subjective Knee Form into a Brazilian version and to test its validity and reproducibility.


METHODS
Cohort study (diagnosis); Level of evidence, 2.


METHODS
The translation of the original IKDC Subjective Knee Form into a Brazilian version was accomplished in accordance with the American Orthopaedic Society for Sports Medicine guidelines and was tested in 32 patients with knee pathologic conditions to develop the first Brazilian version. To test validity and reproducibility, 117 patients with several knee complaints completed the Brazilian IKDC Subjective Knee Form, the Short Form 36 (SF-36), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the Lysholm score. From these patients, 85 were retested within a week to achieve reproducibility. The validation was addressed by correlating the Brazilian IKDC Subjective Knee Form to the other outcome measures. The reproducibility was tested by measuring internal consistency, test-retest reliability, and agreement.


RESULTS
The Brazilian IKDC Subjective Knee Form was highly related to the physical component summary of the SF-36, the Lysholm score, and the WOMAC, and weakly related to the mental component summary of SF-36 (r = .79, .89, .85, and .51, respectively). The internal consistency was strong, with a Cronbach alpha value of .928 and .935 in the test and retest assessment, respectively. The test-retest reliability proved to be excellent, with a high value of the intraclass correlation coefficient (.988), as well as the agreement, demonstrated by the low differences between the means of the test and retest, and the short limit of agreement, observed in the Altman-Bland and survival-agreement plots.


CONCLUSIONS
The results of this study provide evidence that the Brazilian IKDC Subjective Knee Form has psychometric properties similar to the original version. In addition, it was a reliable evaluation instrument for patients with knee-related problems.
Metsavaht
Leonardo
L
Instituto Brasil de Tecnologias da Saúde-IBTS, PO Box 22410-003, Rua Visconde de Pirajá, 407, Room 307, Ipanema, Rio de Janeiro, Brazil. leo@brasilsaude.org
Leporace
Gustavo
G
Riberto
Marcelo
M
de Mello Sposito
Maria Matilde
MM
Batista
Luiz Alberto
LA
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001938:Brazil; D015331:Cohort Studies; D003466:Cultural Characteristics; D005260:Female; D006801:Humans; D007717:Knee / Q000503:physiopathology; D007718:Knee Injuries / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D011594:Psychometrics; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*; D014177:Translations; D055815:Young Adult