An Electronic Osteosynthesis Implant for Continuous Load Monitoring using a Strain Gauge

Abstract

The utilization of strain gauges for monitoring the applied mechanical load to osteosynthesis plates using electronic implants was reported several times in literature. The technique was found to provide valuable information for monitoring the fracture healing process and for improving the rehabilitation. This paper introduces a new electronic osteosynthesis implant, which uses supercapacitors as an energy storage for short term autonomous operation. Moreover, a bluetooth low energy (BLE) transceiver is integrated into the system, which covers larger distances and is less sensitive to misalignment than the commonly used inductive data transmission. This improves the usability of the proposed system for the patients. The system can continuously sample and transmit strain values at a sampling rate of 5 Hz for more than 10 min without being recharged. More than 60 cm of distance in any practically relevant direction can be covered by the BLE data transmission if the implant is placed 5 cm deep in a phantom. The implant dimensions of 20 mm x 16 mm still fit on osteosynthesis plates for larger bones.