KIMIA - a smart wearable for the knee

What it does

A wearable device, powered by patented sensor technology, provides a comprehensive solution for remote rehab where patients' home-exercise sessions and activities of daily living data are shared with therapists in realtime to enable personalized prescriptions.

Your inspiration

Total Knee Replacement (TKR) Surgery is the most common orthopedic procedure globally spearheaded by ageing societies, and the procedure is commonly followed by a long, unengaging, often (perceived as) burdensome rehabilitation period. The rehabilitation field has barely seen changes in the past 50 years and the advent of ageing populations have only proven to worsen the already overburdened healthcare workforce. The need for efficient, highly efficacious treatment is imperative and we believe the recent advancement of wearable IoT technology, now as the forefront of personal health monitoring, is the key to break the field.

How it works

The device is worn on the knee via medical grade adhesive tapes and clip-ons that are waterproof and can be worn for days on end. The magnetic clip-ons allow for easy (dis)mount and double as hall-effect switches to turn the sensor ON/OFF. The main flex sensor is a conductive material that incites small electrical changes when the user bends the knee during exercise. These changes are used to continuously compute, to superior accuracy (error <2°), the knee joint angle, a key parameter used by clinicians for diagnosis/prescription. Coupled with proprietary flex, accelerometer and temperature sensors, type of exercise (squats, walking, etc), position events (standing, sitting, etc) among others can be computed to give a comprehensive view of the status of recovery, driving decision-making for clinicians. Parameters are transmitted via Bluetooth to paired devices or uploaded to a cloud to be accessed remotely by clinicians.

Design process

We started off with 2 separate Inertial Measurement Units (IMUs) that were mounted individually by a large adhesive tape that completely covered them. These IMUs would cross-talk via Bluetooth Low Energy (BLE) to compute the knee joint angle. Then a separate BLE would transmit this information to paired devices for real-time viewing. While the prototype worked, accuracy and usability were muddled by a clunky wearing process, user inconsistency in placement of IMUs and sensor drifting which required constant recalibration. It became apparent to us that the IMUs should have a fixed distance apart to improve the placement problem. We transitioned our IMU sensor system to a patented flex sensor technology, which greatly reduced the sensor drifting, improved accuracy and also created room for additional components like accelerometers and temperature sensors, and more powerful microprocessors to be added which expanded the number of parameters we could monitor. Based on clinical feedback, we improved the look and feel of the device when mounted. We modified the adhesives to be more invisible and had the casing to be a sleek, matte finish, to reduce the stigma of wearing the device. The hall-effect switches were later added to improve usability and product stickiness.

How it is different

Current products on the market tend to use nylon straps or bands coupled with IMU sensors. These products are not designed for continuous 24/7 monitoring because the mounting system used has a tendency of slipping, or shifting which amounts to measurement error, and as such is only limited to session monitoring. For clinicians, key decisive factors include information on daily activities which measures functional mobility. Our adhesives do not slip. Coupled with efficient energy usage of the device, we ensure a continuous, passive monitoring of all activities for days on end. Products on the market require constant recalibration of the sensors due to inconsistent placement. Since our peripheral components (adhesive tapes and clip-ons) can remain mounted during bathing and sleep, placement of the device is consistent. Anytime the user wishes to use the device, he/she can easily mount the main unit which turns ON automatically, without need for calibration again.

Future plans

We’re focusing on developing an engaging UI. Since effectiveness of rehabilitation begins with patient compliance, making our device fun and interactive can alleviate this problem. In other developmental areas, we’re thinking of incorporating EMG (electromyography) sensors to measure muscle strength and usage to give another level of analysis for clinicians and patients. In the future, we would like to expand the application of our sensor to include other joints such as the ankle, hip, shoulder and neck which all suffer from very similar forms of patient non-compliance in rehabilitation, to give more freedom and choice in usage of KIMIA.

Awards

Top10-Make It In China 2019 Winner-Asia Hardware Battle SG 2019 Top3-Hangzhou International Entrepreneurship Comp Winner-Shezhen Entrepreneurship Comp 2018 Winner-ST Electronics Techfactor Challenge 2018 Winner-A*STAR IoT Hackathon 2015 Winner-Aging 2.0 Global Start-up Search 2016