Micromachined Tactile Sensor Array for RTSA

Area of Science:

• Biomedical Engineering
• Materials Science
• Orthopedic Surgery

Background:

• Reverse total shoulder arthroplasty (RTSA) requires precise soft tissue tensioning for optimal outcomes.
• Accurate measurement of glenohumeral joint forces is crucial during RTSA procedures.
• Existing methods for assessing joint forces during RTSA have limitations.

Purpose of the Study:

• To develop and validate a polymer-based tactile capacitive sensor for quantifying joint reaction forces in RTSA.
• To enable real-time measurement of four components of glenohumeral contact forces.
• To assist surgeons in achieving optimal soft tissue tensioning and implant fit.

Main Methods:

• Fabrication of a polydimethylsiloxane (PDMS) dielectric layer with an electrode array using soft lithography.
• Integration of the capacitive sensor within a 3D-printed replica of an RTSA prosthesis.
• Testing the sensor's performance under static loading conditions in simulated shoulder positions.

Main Results:

• The sensor demonstrated a loading time of approximately 400 ms at 14.13 kPa.
• Achieved a sensitivity of 1.24 × 10^-3 pF/kPa at a load of 1649 kPa.
• Provided graphical pressure distribution across the glenohumeral joint, enabling intuitive analysis.

Conclusions:

• The developed sensor can accurately measure joint reaction forces during RTSA.
• This technology can aid in selecting appropriate implant sizes and offsets for patient anatomy.
• Potential to reduce postoperative complications like dislocation and scapular stress fractures.