Osteoarthritis (OA) is a condition in which the cartilage inside joints gradually breaks down, causing bones to rub directly against each other and resulting in significant pain. People living with knee OA experience this pain most acutely when navigating stairs, where the forces on the knee joint are far greater than on flat ground. Our engineering goal was to improve mobility for individuals with knee osteoarthritis, particularly during stair navigation, by reducing pain and limiting harmful knee collapse under load.

We explored three distinct designs before arriving at our final prototype.

Design 1 (Pneumatic Knee Brace): A brace that uses air pressure to provide dynamic support around the knee joint during movement.

Design 2 (Linear Exoskeleton): A rigid external frame that runs alongside the leg to offload force from the knee during stair climbing.

Design 3 (Torsion Spring Brace): A brace that uses a torsion spring to store and release energy, assisting knee extension during stair navigation.

After evaluating all three against our functional and physical requirements, including pain reduction, knee collapse reduction, mobility range, comfortability, weight, and adjustability, we selected the torsion spring approach as the basis for our final design.

Our final prototype is an adaptive angle knee brace that uses an IMU (Inertial Measurement Unit) sensor to continuously calculate the current angle of the knee and identify which stage of stair navigation the user is in. The brace responds in real time, providing the appropriate level of resistance and support at each phase of the stair-climbing motion. The prototype was 3D printed and integrated with an ESP32 microcontroller, IMU, and motor to drive the adaptive mechanism.

Testing across four design studies showed a 46% reduction in average pain rating and a 39% reduction in knee collapse angle when wearing the brace, both satisfying our Level 1 design criteria.