Toward Self-Powered Load Imbalance Detection for Instrumented Knee Implants Using Quadrant Triboelectric Energy...

Area of Science:

• Biomedical Engineering
• Materials Science
• Mechanical Engineering

Background:

• Knee implant loosening is a major cause of implant failure.
• Accurate monitoring of load distribution on the tibial tray is crucial for implant longevity.
• Existing monitoring methods may lack self-powering capabilities or real-time feedback.

Purpose of the Study:

• To develop and evaluate a triboelectric nanogenerator (TENG) as a self-powered pressure sensor for measuring load imbalance on the tibial tray.
• To investigate the potential of TENGs for early detection of knee implant loosening.
• To assess the power harvesting capabilities of the TENG system.

Main Methods:

• A segmented quadrant design TENG pressure sensor with various micro-patterns (pyramid, cylindrical, bar) was proposed.
• Experimental testing was conducted to evaluate sensing capabilities and power harvesting under axial forces.
• The relationship between quadrant output and axial force was determined to characterize sensor performance and find the center of pressure.

Main Results:

• The TENG pressure sensors demonstrated varying sensitivity across different quadrants, enabling axial force measurement.
• A clear relationship between each quadrant's output and the applied axial force was established.
• The system successfully characterized self-powered sensor performance and enabled the determination of the center of pressure.
• Under a 2200 N walking load, each quadrant produced measurable apparent power at 1 Hz and 2 Hz.

Conclusions:

• The developed TENG-based pressure sensor is a viable self-powered solution for monitoring load imbalance on tibial trays.
• Detecting shifts in the center of pressure can serve as an early indicator of knee implant loosening.
• The TENG system exhibits potential for both sensing and energy harvesting in instrumented implants.