Novel Alignment Angle Sensor for Limb Prostheses
Researchers from University of Pittsburgh have invented an alignment angle sensor to allow for optimization of prosthetic limbs improving fit, efficiency and user comfort.
Description
Over one million people in the US live with lower limb loss, with this number expected to increase significantly in the coming decades due to the rise in diabetes, trauma, and cancer. Prosthetic limbs often have multiple components, for example, a foot linked to a lower leg section at a fixed angle using a pyramid connector. To optimize the user experience and reduce the risk of further musculoskeletal issues, prosthetic limbs should be personalized to the user such as the connecting angles of various components in the prostheses. This invention allows for more accurate, efficient, and systematic alignment of angles in prosthetic limbs, improving the quality of life of patients.Applications
1. Optimization of prosthetic limb fit and efficiency2. Design of new prosthetic limbs and joints
Advantages
Current approaches to adjusting the alignment angles between prosthetic components involves tightening or loosening four screws in pyramid adaptors connected to prosthetic knee joints, sockets, and spacers. However, there are challenges in quantifying and documenting these adjustments. Practitioners often rely on counting screw rotations, which may not be easily replicated, and parallax errors can also occur. Incorrect angle alignment in prosthetic limbs can lead to increased wear and tear, increased noise from the prosthesis, and joint or muscle pain for the user.This novel approach is based on an array of Hall-effect sensors, housed in a removable cuff designed to fit around the modular adapters connecting elements of the prosthesis. Using a small permanent magnet connected to existing pyramid connectors, the angle of adjustment is determined by the Hall-effect sensors. This approach allows for an accurate measurement, and rapid readjustment of alignment angles as and when required following natural wear and tear.
This novel sensor can be conveniently introduced to clinics and fitted to existing prosthetic limbs without any special adjustments.