Cross-cultural adaptation and psychometric validation of the Persian version of the University of California, Los Angeles, activity scale in patients following total knee arthroplasty

Abstract

INTRODUCTION: The University of California Los Angeles (UCLA) Activity Scale is a widely used score used to assess physical activity. No reliable Persian validation of the UCLA score in Total Knee Arthroplasty (TKA) patients exists. This study aims to translate, culturally adapt, and validate the Persian version of UCLA (p-UCLA) activity scale in TKA patients. METHODS: Following the established cross-cultural guidelines, the UCLA activity scale was translated to Persian using forward-backward translation. A total of 104 TKA patients completed the p-UCLA, Oxford Knee Score (OKS), International Documentation Committee Subjective Form (IKDC-SF), and Forgotten Joint Score-12 (FJS-12). Construct validity was assessed using the Spearman Correlation coefficient, while reliability was evaluated using the intraclass correlation coefficient (ICC) and Bland-Altman analysis. Floor and ceiling effects were examined. RESULTS: The p-UCLA showed excellent test-retest reliability (ICC = 0.98; P < 0.001). Construct validity was supported by moderate to strong correlation with OKS (r = 0.75-0-78; p < 0.001), IKDC-SF (r = 0.34-0.66; p < 0.001), and FJS-12 (r = 0.69; p < 0.001). No floor or ceiling effect were observed. Bland- Altman analysis showed minimal bias and high measurement stability. CONCLUSION: The p-UCLA activity scale is a reliable and valid instrument for assessing activity levels in Persian patients after TKA. LEVEL OF EVIDENCE: III.