Test-retest reliability of the L-Test in patients with advanced knee osteoarthritis.

Background: The reliability of tests to be used in research or clinical practice should be established for each population specific to their intended use. Reliability is important because it allows correct evaluations to be made about treatment effects or about the amount of changes.Objectives: To evaluate the test-retest reliability and minimal detectable change of the L-test in patients with advanced knee osteoarthritis (OA).Methods: The intraclass correlation coefficient (ICC2,1) was used to assess the test-retest reliability of the L-test. The minimal detectable change with 95% confidence interval (MDC95) was calculated to determine the true change. The inclusion criteria were diagnosis of knee OA, had Kellgren Lawrence Grade IV and age of ≥40 years.Results: Twenty-five participants who met the inclusion criteria were included. Five were male and the mean age was 62.32±9.77 years. All of the participants had radiographic findings indicative of Kellgren-Lawrence Grade IV. The L-test showed excellent test-retest reliability. The ICC was 0.99, the SEM and the MDC95 was 1,90 and 5.28 seconds, respectively.Conclusions: The L-test is a reliable outcome measurement for the assessment of walking ability in patients with advanced knee OA, and it showed very high test-retest reliability in these patients. This test may assist clinicians and researchers in assessing the functional mobility of patients and planning rehabilitation in patients with advanced knee OA.