AB1284-HPR RELIABILITY OF STEP TEST IN SUBJECTS WITH TOTAL KNEE ARTHROPLASTY

Abstract

Background:Patients with TKA show impairments in standing balance up to 1 year after surgery. The impaired standing balance in TKA patients was found to be associated with falls risk and decreased functional level. Assessing of standing balance with objective and reliable assessments tools would therefore be extremely useful for determining accurate exercise program, and risks of falling, especially during the rehabilitative period when ambulation is at its most unsteady (1, 2). The stepping maneuver requires adequate strength and motor control to stabilize the body over the stance limb while the other leg is stepping, therefore the Step Test (ST) provides significant information for dynamic standing balance and lower limb motor control (3). The reliability of ST is reported in patient groups such as stroke, however, there is not any study that investigates the reliability of ST in patients with TKA in the current literature.Objectives:The purposes of this study were to determine the test-retest reliability and the minimal detectable change (MDC) of the ST in patients with TKA.Methods:40 patients with TKA due to knee osteoarthritis, operated by the same surgeon, were included in this study. Patients performed trials for ST twice on the same day. Between the first and second trials, patients waited for an hour on sitting position to prevent fatigue. The ST assesses an individual’s ability to place one foot onto a 7.5-cm-high step and then back down to the floor repeatedly as fast as possible for 15 seconds. The score is the number of steps completed in the 15-second period for each lower extremity. Scores for each lower extremity were recorded separately. Prior to the testing, the ST was demonstrated by the tester and all participants were allowed to a practice trial.Results:The ST showed an excellent test-retest reliability (ICC2,1=0.95) in this study. Standard error of measurement (SEM) and MDC95for ST were 0.37 and 1.02, respectively.Conclusion:This study found that the ST has an excellent test–retest reliability in patients with TKA. It is an effective and reliable tool for measuring dynamic standing balance and participant falls. As a performance-based clinical test, the ST is easy to score, can be applied in a short time as part of the routine medical examination. Therefore, inclusion of ST into a more comprehensive battery of performance-based measures of standing balance and lower limb motor control function in subjects with TKA should be considered.