Exercise adherence to prescribed therapy is as low as 35%, especially in Total Knee Replacement (TKR) therapy. Non-adherence has been shown to prolong or preclude recovery, negatively influence patient outcomes, and increase healthcare costs. There are currently a total of 700,000 TKR patients and is expected to grow by over 600% by 2030. Currently tele-rehabilitation solutions are limited by a lack of portable, precise, and cost-effective tools. The InterACTION system consists of two parts: a wearable, portable, motion capture device and a web-based software application for managing and communicating joint function data to a remote therapist. This will reduce costs, and increase compliance and communication between patient and therapist. The Coulter funding will facilitate a clinical trial enrolling 60 post-operative patients for 6 months to track product adoption, exercise adherence, and patient outcomes.