Embedded sensing package for temporary bone cement spacers in infected total knee arthroplasty

Area of Science:

• Biomedical Engineering
• Orthopedic Surgery
• Infectious Disease Management

Background:

• High re-infection rates (15%) after two-stage total knee arthroplasty (TKA) revision underscore challenges in verifying infection clearance.
• Current methods lack definitive indicators for successful eradication of infection between revision stages.

Purpose of the Study:

• To design and evaluate a telemetric sensor system for integration with bone cement spacers.
• To measure knee joint temperature to potentially indicate infection status post-TKA revision.

Main Methods:

• Developed a telemetric sensor package to measure knee joint temperature within bone cement spacers.
• Empirically determined sensor package precision, accuracy, hysteresis, and thermal equilibrium.
• Conducted cadaveric testing with cyclic loading (30,000 cycles) and evaluated sensor performance and mechanical integrity.

Main Results:

• Sensor package demonstrated accuracy of ±0.24°C and precision of 0.09°C with negligible hysteresis.
• The system allowed data logging for 6 weeks via Bluetooth transmission.
• No mechanical integrity issues were found in the bone cement spacer or sensor after testing.

Conclusions:

• The telemetric embedded sensor system shows promise for monitoring knee joint temperature.
• This technology could aid in managing infection treatments for total knee arthroplasty revision.
• Further clinical validation is necessary before patient application.