Abstract: A system for monitoring a joint of a patient includes multiple sensors to be disposed near a joint and to measure or observe actions or physical quantities associated with the joint; and at least one communications module coupled to the sensors to receive data from the sensors and to transmit sensor information to an external device. The system also includes a patient device and clinician device which can be used to, for example, monitor and display information obtained from the sensors, determine range of motion measurements from the sensor data, show progress in physical therapy, take a photograph or video of the site on the patient, obtain a pain score, and include friends for providing encouragement during physical therapy.