Reliability and Concurrent Validity of the Four Square Step Test in Osteoarthritic Knee Patients

Research has demonstrated reduced dynamic standing balance in people with knee osteoarthritis, but reliable studies appropriate for clinical use have not been assessed. This study looked to assess the validity and reliability of the Four Square Step Test in patients with knee osteoarthritis. A randomised observational, repeated measures study design for inter-rater and intra-rater reliability was completed in men and women with knee osteoarthritis (N=62). In this cohort study, patients completed a baseline assessment including the Four Square Step Test, Berg Balance Scale and Figure of 8 Walk Test, and returned within a four-week period to be reassessed to determine the inter and intra-rater reliability of the Four Square Step Test. The Four Square Step Test, F8W, and Berg Balance Scale were shown to have significant concurrent validity (p < .001, r= 0.803, 0.838, and -0.777 respectively). Over a four-week period intra-raterreliability the Four Square Step Test was significantly reliable (ICC=0.89, lower 95% CI = 0.809). The Four Square Step Test displayed optimal inter-rater reliability between two assessors during assessment two (ICC = 0.983, lower 95% CI = 0.976). The FSST has been shown to be an appropriate measure of dynamic standing balance in knee osteoarthritis patients and is recommended for clinical use