Mobile app to support home exercise adherence in knee osteoarthritis: A randomized clinical trial

Determine if a mobile app alongside a home strength program improves exercise adherence and/or function in knee osteoarthritis.

2-arm superiority randomized clinical trial in adults with knee osteoarthritis and physical dysfunction. Both groups received physiotherapist-prescribed strength exercises (prescribed thrice weekly). Intervention group also received the 'My Exercise Messages' app (provides exercise tracking, goal-setting and behavior change messages). Two self-reported primary outcomes measured: i) number of days exercises were performed over prior fortnight (ordinal outcome dichotomized as "complete adherence" [score 6 or more] or "incomplete adherence" [scores 0-5]) and ii) change in function (Western Ontario and McMaster Universities Osteoarthritis Index, 0-68), at 14 weeks (secondary end-point) and 26 weeks (primary end-point). Secondary outcomes included knee pain; sport/recreation function; knee-related quality of life; physical activity; exercise self-efficacy; global change; satisfaction; another exercise adherence measure; and joint replacement willingness.

Of 182 people (mean (SD) age 63.5 (8.1) years, 126 (69%) women) randomized, 171 (94%) and 173 (95%) provided primary outcomes at 14 and 26 weeks respectively. At 26 weeks, the exercise plus app group were more likely to be completely adherent (n=31 (36%) versus n=14 (16%) in exercise only) to prescribed exercise frequency (relative risk [95% CIs], 2.1 [1.4, 3.2], p<0.001) but function was not different (mean difference [95% CIs], -0.9 [-3.9, 2.12], p=0.52). Results were similar at 14 weeks. Secondary outcomes did not differ, except Exercise Adherence Rating Scale, favoring exercise plus app.

The app improved exercise adherence but this did not translate into improved function.