Development of a Highly Sensitive Micropyramid Flexible Pressure Sensor Array for Intra-Acetabular Pressure Field Monitoring

Total Hip Replacement (THR) surgery has achieved significant success in alleviating pain from hip joint diseases and improving patients’ quality of life. However, the challenge of precisely placing the acetabular implant during surgery can lead to complications such as early loosening and wear of the implant. Traditionally, this critical step relies on the surgeon’s experience and subjective judgment, lacking objective tools to monitor the pressure field within the acetabulum in real-time. This study presents the development of a highly sensitive micro-pyramid flexible sensor array, fabricated using micro-fine photolithography precision molding technology, for assisting pressure field monitoring in the acetabulum during THR. The compression of the pyramid microstructure results in large changes in contact area, allowing our single sensor to exhibit an ultra-high sensitivity of 11711.95 kPa⁻¹ within the 0-90 kPa pressure range, with a response/recovery time of 120 ms/81 ms. Six independent sensors were integrated into a customized acetabular implant model, enabling the collection of pressure field data from the acetabulum. To simulate the surgical process, we modified the test platform, developed corresponding signal acquisition circuits, and a software system for real-time visualization of pressure distribution in the acetabulum, demonstrating the potential application of this system in assisting surgeons in precisely placing implants during THR surgery.