Objective: To compare the effectiveness of a new interactive virtual telerehabilitation system and a conventional programme following total knee arthroplasty. Design: Randomized, controlled, single-blind clinical trial. Participants: A total of 142 total knee arthroplasty patients. Methods: Participants were randomly assigned to receive either: (i) conventional out-patient physical therapy; or (ii) interactive virtual telerehabilitation system. The main outcome was function assessed with active range of knee movement. Other variables, such as muscle strength, walk speed, pain and the Western Ontario and McMaster Universities Osteoarthritis Index, were also collected. Comparisons were made on the basis of data collected routinely before surgery, at the end of the rehabilitation programme, and at 3 months follow-up. Quantitative variables were compared by Mann- Whitney U test. The agreed alpha risk for all hypothesis testing was 0.05. Results: Baseline characteristics between groups were comparable. All participants improved after the 2-week intervention on all outcome variables (p < 0.05). Patients in the interactive virtual telerehabilitation group achieved improvements in the functional variables similar to those achieved in the conventional therapy group. Conclusion: A 2-week interactive virtual telerehabilitation programme is at least as effective as conventional therapy. Telerehabilitation is a promising alternative to traditional face-to-face therapies after discharge from total knee arthroplasty, especially for those patients who have difficulty with transportation to rehabilitation centres. © 2013 The Authors.