Intertester and Intratester Reliability of Functional Movement Tests by Trained Testers in Community-Dwelling Older Adults With Knee Osteoarthritis: A Cross-sectional Study

Background and Purpose: Movement quality of the lower extremities is considered an indicator of functional status in older adults with knee osteoarthritis (OA), and visual assessment of movement quality during functional movement tests can identify movement dysfunction and predict factors associated with lower extremity injuries. This study investigated the intertester and intratester reliability of trained testers for functional movement tests in community-dwelling older adults with knee OA. Methods: This study was a cross-sectional study. A total of 43 older adults with knee OA were recruited for this study and performed 2 functional movement tests: squat and step-down. Movement quality during the functional movement tests was visually rated in segmental (trunk, pelvic, knee, and foot) and overall regions and was scored from 0 (acceptable) to 3 (marked dysfunction). Percentage of agreement and weighted kappa coefficients were used to explore the reliability between and within testers. Results: The intertester reliability of the functional movement tests showed weak to strong agreement (weighted kappa values from 0.44 to 0.88); the percentage agreement ranged from 52.78% to 93.02%. The intratester reliability of the functional movement tests showed weak to strong agreement (weighted kappa values from 0.57 to 0.88); the percentage agreement ranged from 69.77% to 93.02%. Conclusions: Visual assessment of functional movement tests showed weak to strong intertester and intratester reliability to examine movement quality in community-dwelling older adults with knee OA. Thus, while it may be useful in a clinical setting to assess movement dysfunction segmentally and generally in older adults with knee OA; greater efforts would be needed to ensure high levels of agreement of functional movement tests.