168 patients with symptomatic knee osteoarthritis were randomized to either telephone coaching over 6 months or a control group, in addition to a physiotherapist-prescribed home-based exercise therapy program. The purpose of this study was to evaluate if sessions of telephone coaching during the intervention period were associated with a significant increase in program efficacy (ie. pain and functional outcome), as well as adherence to the program. Results demonstrated no significant difference between groups in improvement in pain and functional outcomes after 6 months, despite significantly increased physical activity levels and adherence to home exercises. Results at 12 and 18 months were reported to not significantly differ between groups.