Battery-Powered Wearable Device Monitors Joint Pain

Ankle injuries are common among active Americans. Each day, approximately 25,000 people experience ankle sprains, and 25% of Americans regularly deal with knee pain. However, physical therapy can be both expensive and time-consuming, and online rehabilitation programs often lack the precision needed for effective recovery. To address this, a new wearable device has been developed to monitor joint pain and allows both individuals and their healthcare providers to track joint health in real-time.

The device, named Arthroba, was created by researchers at the Georgia Institute of Technology (Atlanta, GA, USA). It uses electrical sensors to monitor swelling and tissue damage in the knee, ankle, and other important joints. Healthy joints maintain a delicate balance of fluid between the bones, tendons, ligaments, and cartilage. When this balance is disturbed—either through too little fluid leading to arthritis and stiffness, or excess fluid causing swelling—pain and mobility issues often follow. Arthroba utilizes bioimpedance analysis, which involves electrically sensing tissue, to assess swelling, damage, and the adequacy of soft tissue support around the joint.

Changes in the composition of joint tissue due to swelling or injury can interfere with the electrical current, which Arthroba detects. The device uses four dry electrodes placed around the knee to measure the fluid accumulation and its movement within the joint, providing more targeted insights for physical therapy. In addition to detecting swelling and muscle tears, Arthroba includes an inertial measurement unit that tracks the joint's acceleration, rotation, and velocity. This comprehensive data offers new insights into joint health and allows for the optimization of treatment protocols. Users can wear the device while performing rehabilitation exercises to prevent overuse. With its objective measurements, Arthroba enables personalized therapy adjustments that would typically require frequent in-person evaluations by skilled therapists.

Arthroba functions similarly to body mass composition scales but focuses on a specific piece of tissue. The changes measured through the device's app correlate with many of the symptoms physiotherapists use to recommend exercises. This data is sent via Bluetooth to a mobile app, which uses artificial intelligence to provide exercise suggestions. Medical professionals can also utilize the data to create personalized recovery plans. Although Arthroba was initially designed for knee monitoring, the researchers have collaborated with Georgia Tech baseball players to study elbow injuries and have worked with juvenile arthritis patients. They see potential for this technology to not only aid in recovery but also serve as a preventive care tool. With multiple patents and the development of a startup, Arthroba is positioned to be worn by everyday users, much like a smartwatch.

“People want to keep playing tennis or pickleball without a lot of knee pain, injury, or risk,” said Omer Inan, Regents’ Entrepreneur and Linda J. and Mark C. Smith Chair in the School of Electrical and Computer Engineering. “Arthroba could be key to that.”