Turkish Validity and Reliability of the Marx Activity Rating Scale (MARS) for Patients with Knee Problems

Objective: The Marx Activity Rating Scale (MARS) is a recently developed in English to assess patients’ who have knee problems activity level. However, there is no Turkish validation for it. Materials and Methods: MARS was translated into Turkish language according to the recommended stages by Beaton et al. 100 Patients (mean age, 30.9 ± 10.5) with various types of the knee problems were included. Each participant completed the MARS twice at fourteen day intervals to determine the test-retest reliability using the interrater correlation coefficient and Cronbach\'s alpha evaluating internal-consistency. Spearman\'s “rank correlation” coefficient was done to measure construct validity between the MARS, the EUROQoL General Quality of Life Scale (EQ-5D), the International Knee Documentation Committee (IKDC) Scale. Results: A total of 100 patients (37 females, 63 males) completed the Turkish-language MARS. The reliability of the test-retest was 0.9, with Cronbach\'s alpha of 0.8 at the initial and 0.7 for the retest. High correlations were found between the IKDC and MARS (r =0.2). MARS also strongly correlated with the EQ5D-VAS component score (r =0.2). Floor or ceiling effects were not found for the overall MARS score. Conclusion: In conclusion, the MARS was found to be valid and reliable. It is considered to be a preferable scale for patients with knee problems.