The integration of advances in the areas of information technology and robotics in telemedicine infrastructures has strengthened the health systems of different countries. In this sense, this approach has increased the quality of the service in terms of ease of access and expansion of coverage, minimizing the risk of personnel being exposed to contagious pathologies, such as Covid-19. However, a correct integration in these applications demands the consideration of fault diagnosis and isolation. With this objective, this work focuses on a methodological development based on models applied to a teleoperated technical aid via the internet for the execution of rehabilitation protocols of passive therapies in the knee. For this, it is used bond graph as modeling tool. The information generated allowed to define a set of redundant analytical relationships used to detection of faults and insolation of them in an electromechanical component of the rehabilitation system.