AB0883 RELIABILITY OF THE MODIFIED FOUR SQUARE STEP TEST IN PATIENTS WITH REVISION TOTAL KNEE ARTHROPLASTY
Authors: B. Unver, K. Sevik, V. Karatosun
Journal: Annals of the Rheumatic Diseases (2020)

Background: Patients with total knee arthroplasty (TKA) often experience pain and reduced balance control, which may predispose them to greater fall risk. The patients with revision total knee arthrooplasty (rTKA), have more pain, stiffness and physical dysfunction and less postoperative improvement compared to the patients with TKA [1]. Falls in people with gait or balance disorders have significant consequences. Fear of falling can also predispose people to inactivity, which can lead to problems of debilitation, increased handicap, and disability by itself. Most of the falls take place in the course of movement, and the trips and slips were determined as the most common cause of elderly falls. Trips are responsible of falls between 40% to 60% and slips between 10% to 15%, showing that the capability to take a quick step would prevent many falls [2]. Literature has found stepping speed to the different directions declines with aging and are lesser for fallers than for nonfallers [3]. Modified four square step test (mFSST) was developed to assessing fall risk and dynamic balance by scoring time while participants stepping in multiple directions but its reliability has not been investigated in patients undergoing rTKA. Objectives: The aims of this study were to determine the test-retest reliability and the minimal clinically important change (MCID) of the mFSST in patients with rTKA Methods: mFSST administered on 22 patients undergoing rTKA. mFSST is performed by using tapes to make one horizontal and one vertical line like a cross to create 4 quadrants. Patients’ performances were timed as patients were successfully stepping clockwise and counter-clockwise while avoid touching on tapes, turning their body or losing balance. Two trials performed and patients rested between trials and were encouraged to rest as often as they required to prevent fatigue. Results: ICC (2.1) for mFSST was 0.83. The standard error of measurement and MCID were 0.67 and 1.85 respectively (95 %. confidence level). Conclusion: The mFSST has a good test-retest reliability in patients with rTKA. It is a reliable and responsive tool for measuring fall risk, dynamic balance and mobility. The mFSST is an excellent measure of gait variability, stepping in multipl directions and dynamic balance, also can easily identify real clinically important changes in patients with rTKA in simple environments and minimal equipment. References: [1]Järvenpää J, Kettunen J, Miettinen H, Kröger H. The clinical outcome of revision knee replacement after unicompartmental knee arthroplasty versus primary total knee arthroplasty: 8–17 years follow-up study of 49 patients. International Orthopaedics 2010; 34: 649-653. [2]Cumming RG, Klineberg RJ. Fall frequency and characteristics and the risk of hip fractures. Journal of the American Geriatrics Society 1994; 42: 774-778. [3]Medell JL, Alexander NB. A clinical measure of maximal and rapid stepping in older women. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences 2000; 55: M429-M433. Disclosure of Interests: None declared