Reliability and validity of the Turkish version of the knee injury and osteoarthritis outcome score-physical function short-form (KOOS-PS)

Abstract

Background:

The Knee injury and Osteoarthritis Outcome Score-Physical function Short-form (KOOS-PS) is a disease-specific questionnaire that can be used to evaluate physical function in patients with knee problems and it has not been adapted to Turkish language.

Objective:

The purpose of the present study was to adapt the KOOS-PS to the Turkish language and to evaluate the psychometric properties of the Turkish version of the KOOS-PS in patients with primary knee osteoarthritis.

Methods:

The translation from the source language to the target language, synthesis, back-translation, revision and pre-test stages were performed. A total of eighty patients participated in the study. Internal consistency was tested by Cronbach’s alpha, test-retest reliability was tested by the intra-class correlation coefficient (ICC). Construct validity was investigated with Spearmann’s rank correlation coefficient and correlations of the KOOS-PS with the WOMAC and Lequesne osteoarthritis indexes and with the duration of complaints, radiological grade and range of flexion were assessed for this purpose.

Results:

Internal consistency was good, with a Cronbach’s alpha of 0.904 and an ICC value of 0.839 certifying that the Turkish KOOS-PS is a reliable tool. Spearman’s rank correlation coefficients between the KOOS-PS and the overall WOMAC ( $\mathit{r}=0.764$ ), WOMAC-physical function ( $\mathit{r}=0.754$ ), WOMAC-pain ( $\mathit{r}=0.706$ ), overall Lequesne ( $\mathit{r}=0.775$ ), Lequesne-daily living activities ( $\mathit{r}=0.737$ ) and Lequesne-pain ( $\mathit{r}=0.716$ ) were high. Moderate correlations were found between the WOMAC-stiffness, Lequesne-walking distance and KOOS-PS ( $\mathit{r}=0.599$ and 0.528, respectively).

Conclusions:

The Turkish KOOS-PS was found to be reliable and valid for patients with primary knee osteoarthritis.