Lower-Limb Muscle Force is related with Physical Activity in Older Adults Undergone Total Knee Replacement

Research Objectives To investigate the relationship between physical function and knee-related symptoms and 8-month physical activity (PA) level in older adults undergone total knee replacement (TKR). Design The 8-month follow-up after the randomized controlled trial (RCT) comparing exergaming with standard post-TKR exercise (NCT03717727). Setting N/A. Participants Originally 52 random sample of individuals undergoing TKR surgery participated in a 4-month post-operative exergaming trial (RCT), after which 40 (mean age 67 years) completed the 8-month follow-up. Interventions Nonexercised, post-intervention follow-up. Main Outcome Measures Self-reported PA including a leisure time PA and PA related to daily errands and commuting was collected during the follow-up period using structured diaries from which metabolic equivalent of task hours (METh) per month were calculated. For analysis, participants were divided into METh tertiles: I, < 13.0 (n=13), II, 13.0-20.9 (n=13), and III, > 21.0 (n=14). Physical function and knee related symptoms were measured after RCT's intervention period using the Oxford Knee Score questionnaire, Timed Up and Go test, visual analog scale, 10-meter walking test, Short Physical Performance Battery, isometric knee extension and flexion force test, and Knee injury and Osteoarthritis Outcome Score questionnaire. Results There was a significant linear relationship between higher post-intervention knee flexion muscle force of the operated lower-limb and higher PA level during 8-month follow-up (P for linearity = 0.002). There was no linear relationship between other variables measuring physical function or knee-related symptoms and PA level. Conclusions Results suggest that a higher knee flexion muscle force of operated lower limb after rehabilitative intervention period has positive impact on the long-term PA during leisure time, daily errands and commuting in the older adults recovering from TKR surgery. Author(s) Disclosures The authors have no conflicts of interest to disclose.