Smart wearables for health monitoring, prevention, and patient support play a significant role in today’s treatment and home rehabilitation. The effectiveness of rehabilitation in acute cruciate ligament (CL) rupture is dependent upon patient adherence to personalised Home Exercise Programmes (HEPs) and development of self-efficacy. This paper presents the research, preliminary design stages and a formative evaluation of a digital wearable system for monitoring, tracking, guiding and motivating users during HEP. The aim of the prototype is to support patients’ rehabilitation program by reducing the risk of re-injury during the process and motivate them to adhere to their HEPs by monitoring, providing constructive feedback, encouraging understanding and thus promoting self-efficacy. The digital infrastructure is composed of three main parts, a physical product of two smart bracelets for sensing data from the patient’s knee, a smartphone application for the user to interact with and a web-based service for collecting, storing, analysing, and sharing data. The evaluation of the wearable system was based on a randomised group of 15 subject participants.