Quantifying walking ability in Japanese patients with knee osteoarthritis: Standard values derived from a multicenter study

Background: We aimed to determine useful parameters for quantifying walking ability in patients with knee osteoarthritis. Methods: This study included 621 Japanese patients with knee osteoarthritis scheduled to undergo total knee arthroplasty at any of 14 participating hospitals. Sex, age, body mass index, osteoarthritis severity (Kellgren-Lawrence grade), laterality, prior contralateral surgery, and pain were analyzed for their influence on walking ability, which was evaluated in terms of the 5-m walk test and the Timed Up and Go test outcomes during preoperative hospitalization. Patients were stratified based on dichotomized values of the independent influencing factors of walking ability, and the standard values for parameters describing walking ability were obtained. Results: Multiple regression analysis revealed that sex, age, and Kellgren-Lawrence grade were factors influencing walking ability (5-m walk test and Timed Up and Go test outcomes). Therefore, the patients were stratified by sex, age, and Kellgren-Lawrence grade. The standard values (median values) for walking time on the 5-m walk test among patients aged 60-74/75-89 years were: 3.90/4.64 vs. 4.27/5.12 s for men vs. women with Kellgren-Lawrence grade III; 4.26/5.60 vs. 4.80/6.05 s for men vs. women with Kellgren-Lawrence grade IV. Regarding walking speed on the 5-m test, the standard values were: 1.28/1.08 vs. 1.17/0.98 m/s for men vs. women with Kellgren-Lawrence grade III; 1.17/0.89 vs. 1.04/0.83 m/s for men vs. women with Kellgren-Lawrence grade IV. Finally, the standard values for time on the Timed Up and Go test were: 8.52/10.30 vs. 9.30/11.74 s for men vs. women with Kellgren-Lawrence grade III; 9.40/12.90 vs. 10.05/13.20 s for men vs. women with Kellgren-Lawrence grade IV. Conclusions: The standard values reported in this study can be used to quantify walking ability decline in patients with knee osteoarthritis and to aid in the decision to consider total knee arthroplasty. (C) 2018 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.