Validade de construto e confiabilidade do teste de marcha estacionária de dois minutos em pacientes com osteoartrite de joelho

Abstract

Objective: To validate and evaluate the intrarater and interrater reliability of the 2- minute step test (2MST) in measuring the functional performance of patients with knee pain associated with osteoarthritis. Methods: A sample of 41 patients was used in order to assess the intrarater and interrater reliability 2MST. The interval between the test and re-test being from 7 to 14 days. The intraclass correlation coefficient (ICC2,3) was used to determine reliability, with a 95% confidence interval, standard error of measurement and minimum detectable change. The same number of volunteers was used to test the construct validity using Spearman`s correlation (rho). Therefore, 2MST was correlated with the other instruments used in the study: The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Numerical Rating Scale (NRS), Catastrophic Pain Scale (EPCD) and Chronic Pain Self-Efficacy Scale (CPSS). Results: 2MST presented excellent reliability results, interrater (ICC= 0,97) and intrarrater (ICC= 0,94). All instruments showed a statistically significant correlation with 2MST, except for EPCD. A correlation magnitude above 0,50 was found between 2MST and the WOMAC pain and function domains, and a correlation magnitude between 0,30 and 0,50 with the joint stiffness domain of WOMAC, END at rest and during movement, and QAESD. Conclusion: 2MST proved to be valid for assessing functional capacity in patients with knee osteoarthritis, with excellent intrarater and interrater reliability. The study supports the use of 2MST in the clinical context and in research with patients with pain, associated with knee osteoarthritis.