The goal of this clinical trial is to compare patient-reported and performance-based outcomes of patients followed with a standard exercise program based on telerehabilitation and patients followed with action observation therapy program added to a standard exercise program based on telerehabilitation after total knee arthroplasty surgery. The main questions it aims to answer are: * \[What is the effect of action observation therapy added to a telerehabilitation-based standard exercise program on patient-reported outcomes after total knee arthroplasty surgery?\] * \[What is the effect of action observation therapy added to a telerehabilitation-based standardized exercise program on performance-based outcomes after total knee arthroplasty surgery?\] Participants will be divided into three groups by computer-assisted randomization method: Group 1: home exercise with information leaflet group, Group 2: information leaflet + telerehabilitation-based standard exercise program group, Group 3: information leaflet + telerehabilitation-based standard exercise program + action observation therapy group. Patients in the second and third groups will be followed up with the telerehabilitation method accompanied by a physiotherapist for 30 minutes 3 days a week for 6 weeks after discharge. The third group will receive a standard exercise program 3 days a week and 15 minutes of action observation therapy via video conferencing.