The test-retest reliability and concurrent validity of performance-based task tests in patients with knee osteoarthritis

Abstract

BackgroundThe measurement tool used for an accurate balance assessment should produce valid and reliable results in the population in which it is used. ObjectivesTo examine whether two performance-based task tests are a reliable and valid measurement test to assess balance in patients with early and advanced knee osteoarthritis (KO). DesignReliability and concurrent validity research. MethodTest-retest reliability by calculating the intraclass correlation coefficient (ICC) between the first and second trial periods of performance-based task tests (Alternate Step Test & Pen Pick up Test); their correlations with the Timed Up and Go Test (TUGT) were calculated and their concurrent validity in balance assessment were examined. ResultsA total of 100 patients (75% women, 25% men, mean 59 ± 10 years) with KO, 50 early (54 ± 7 years, 34 women, 16 men) and 50 advanced (64 ± 9 years, 41 women, 9 men), participated in the study. The ICC values for the Alternate Step Test (AST) and Pen Pick up Test (PPT) in patients with early KO are 0.881 (0.747–0.939, 95% confidence intervals) and 0.815 (0.689–0.892, 95% confidence intervals), respectively, while it is 0.852 (0.752–0.913, 95% confidence intervals) and 0.861 (0.756–0.922, 95% confidence intervals) in patients with advanced KO. Pearson correlation coefficient between AST & PPT times and TUGT time in patients with early and advanced KO was in the range of 0.535–0.746 (p < 0.01). ConclusionsBoth task tests are reliable and valid clinical measurement tests that can be used to assess balance in patients with both early and advanced KO.