Reliability and minimal detectable change of the Step Test in patients with knee osteoarthritis

Introduction. The study aim was to evaluate the test-retest reliability and minimal detectable change of the Step Test in patients with knee osteoarthritis. Methods. The intraclass correlation coefficient was used to assess the test-retest reliability of the Step Test. The minimal detectable change with 95% confidence interval (MdC95) was calculated to determine the true change. The inclusion criteria involved a diagnosis of knee osteoarthritis and age of 40 years. Results. Thirty-eight participants who met the inclusion criteria were investigated. Seven were male and the mean age equalled 61.23 ± 9.31 years. Three patients had radiographic findings indicative of Kellgren-Lawrence grade ii, 10 of grade iii, and 25 of grade iV. The Step Test presented excellent test-retest reliability. The intraclass correlation coefficient was 0.97, standard error of the mean was 0.46, and the MdC95 was 1.27. Conclusions. The Step Test is a reliable outcome measurement for the assessment of balance in patients with knee osteoar- thritis, and it showed excellent test-retest reliability in these patients. The test may assist clinicians and researchers in evaluating balance and planning rehabilitation in patients with knee osteoarthritis.