Does physical therapist contact matter? A randomised controlled trial comparing telerehabilitation and booklet-based exercise for knee osteoarthritis

Telerehabilitation is increasingly used in knee osteoarthritis, but its effectiveness compared with structured home exercise and the role of physical therapist contact remain unclear. To address this, we aimed to investigate whether the clinical effectiveness of telerehabilitation for knee osteoarthritis is primarily attributable to the digital platform itself or to the extent and quality of physical therapist engagement within that platform. In this single-centre Randomised Controlled Trial (RCT), 118 patients with knee OA (Kellgren-Lawrence grade I-III) were allocated 1:1 to a 12-week telerehabilitation (TR; n=57) or booklet-based exercise programme (BB; n=61). Within the telerehabilitation group, participants were retrospectively stratified into those with Physical Therapist Contact (TR-C) and those without contact (TR-NC) for an exploratory analysis. Outcomes included knee pain (NRS, Numerical Rating Scale), Range Of Motion (ROM), WOMAC, physical activity (IPAQ), and health-related quality of life (SF-12). A post-hoc exploratory subgroup analysis was conducted and looked at the impact of a physical therapist with and without contact. A key component of the analysis was an exploratory subgroup comparison examining the role of physical therapist contact within the telerehabilitation group. Primary outcomes were analysed using mixed-model ANOVA, with exploratory subgroup comparisons. Both groups showed significant within-group improvements in pain, ROM, and WOMAC scores (all p ≤0.001), with no significant group × time interactions (p >0.05). Exploratory analysis identified significant differences based on physical therapist contact, with greater improvements in pain (p=0.009), knee flexion (p=0.041), and WOMAC Pain (p=0.047) among participants who engaged with the physical therapist. Participants without contact showed the smallest improvements. When stratified by physical therapist contact, participants receiving contact demonstrated greater improvements than those without contact, who showed the smallest gains. Telerehabilitation and booklet-based exercise programme provide comparable clinical outcomes at the group level. However, physical therapist engagement appears to be a key determinant of treatment response. These findings suggest that the effectiveness of TR depends more on clinical interaction than on digital delivery alone. Physical therapist contact may represent an important component influencing the effectiveness of telerehabilitation. It remains unclear whether telerehabilitation effectiveness stems from the digital platform, exercise content, or physical therapist guidance.