Motivating people to train after a knee surgery –

Designing an interactive knee orthotics with an embedded sensor
that supports people after a surgery to exercise daily with a connected app

‘Modelling and prototyping’ elective course | team of 2 students | 2015 | Design for Interaction | Delft University of Technology


Sensi Brace

  • Gives data based training advice and a progress overview
  • Tracks the bending angle during exercising to help patients consciously improve their leg’s flexibility and strength
  • Enhances the user’s understanding of his injury, featuring anatomy explanations
  • Reminders nudge users to keep up with personal training goals & schedules
  • Enables doctors to monitor their patients’ post-surgical rehabilitation progress and correct mistakes in-time

New service system with Sensi Brace

Custom rehab guide

Right after a surgery, the physio therapist gives the knee orthotic to the patient and plan an individual training schedule using the app.

Accurate knee training

During home rehabilitation, patients trains with the app and the sensors inside the orthotic records movements and the healing progress.

Direct expert support

Physio therapists can monitor the healing progress and correct training mistakes in-time. Accurate data is used to have clear conversations.


Key challenges

After a knee surgery, it is important to slowly bend the knee up to a hundred times a day, to carefully push the boundaries. However, people often neglect this, or do not know how they should train correctly at home. Doctors have only short consultation time available to discuss a progress.

Design process

After mapping out the new service journey, we developed the product and app through sketches, wireframing and CAD modelling of free form shapes. The app’s use flow was optimised through paper-prototyping.