Quality Factor (QF) Sensitive LCR Patterns for Orthopedic Implant Strain Monitoring

A QF-sensitive LCR sensor for orthopedic implant strain monitoring is demonstrated for the first time, employing laser-annealed polyether-ether-ketone (LAP) as the highly resistance-sensitive unit. The LAP-based unit achieves a gauge factor (GF) of 350.89, effectively overcoming the limitations of traditional LCR strain sensors, such as short coupling distances, stress mismatch, and susceptibility to environmental interference. The wireless passive sensor successfully enables transmuscular strain sensing with a QF sensitivity of ~350/ε and a coupling distance exceeding 15 mm, meeting the requirements of most orthopedic implant applications. This study provides the first validation of the feasibility of integrating near-field coupling with laser-direct-written resistance-sensitive elements for biomechanical sensing. Furthermore, it contributes to the advancement of smart orthopedic implant technologies.