After total knee replacement surgery, patients usually have to make multiple visits to the hospital for measurement of their knee flexion as part of their recovery process. Often, these visits require long travelling and waiting time, while utilising valuable and scarce medical resources. Our mobile application (Mo-Knee-Tor) aims to provide an alternative through an easy-to-use interface for patients to use their own smartphones to measure, record and transmit measurement records to their doctors and caregivers. This reduces the need for in-person checkups, which is even more valuable given their reduction in mobility post-surgery.