Development of a Wireless Telemetry Sensor Device to Measure Load and Deformation in Orthopaedic Applications

Abstract

Due to sensor size and supporting circuitry, in-vivo load and deformation measurements are currently restricted to applications within larger orthopaedic implants. The objective of this study is to repurpose a commercially available low-power, miniature, wireless, telemetric, tire-pressure sensor (FXTH87) to measure load and deformation for future use in orthopaedic and biomedical applications. The capacitive transducer membrane was modified, and compressive deformation was applied to the transducer to determine the sensor signal value and the internal resistive force. The sensor package was embedded within a deformable enclosure to illustrate potential applications of the sensor for monitoring load. To reach the maximum output signal value, sensors required compressive deformation of 350 ± 24 µm. The output signal value of the sensor was an effective predictor of the applied load on a calibrated plastic strain member, over a range of 35 N. The FXTH87 sensor can effectively sense and transmit load-induced deformations. The sensor does not have a limit on loads it can measure, as long as deformation resulting from the applied load does not exceed 350 µm. The proposed device presents a sensitive and precise means to monitor deformation and load within small-scale, deformable enclosures.

A Novel Capacitive Measurement Device for Longitudinal Monitoring of Bone Fracture Healing

“…Since we were able to work at pre-contact distances (i.e., 2 mm) in our measurement device, we exploited the exponential curve of response of the capacitive sensors to increase the resolution and the accuracy of the sensing technology. Moreover, the performance of a capacitive technology in detecting deformations and loads was already proved [ 43 ], paving the way for future orthopaedic applications.…”

Role of Nanomaterials in the Fabrication of bioNEMS/MEMS for Biomedical Applications and towards Pioneering Food Waste Utilisation

“…Because of advancements in sensor technology, real-time monitoring of various post-operative care and recovery such as fracture healing, early signs of infection determination that could potentially lead to sepsis if not properly assessed and treated, and wound recovery monitoring is now possible [126]. Implantable biosensors are also useful for many invasive implant surgeries (e.g., orthopaedic implants-total knee and hip replacements, spine implants) because they provide real-time implant monitoring or post-implantation data for improved clinical outcomes [5,126]. Anderson, Wilson and Holdsworth [5] demonstrated technical modifications to a MEMS pressure sensor that allowed them to measure changes in deformation up to 350 µm.…”

“…Implantable biosensors are also useful for many invasive implant surgeries (e.g., orthopaedic implants-total knee and hip replacements, spine implants) because they provide real-time implant monitoring or post-implantation data for improved clinical outcomes [5,126]. Anderson, Wilson and Holdsworth [5] demonstrated technical modifications to a MEMS pressure sensor that allowed them to measure changes in deformation up to 350 µm.…”

“…Nanomaterials 2022, 12, x FOR PEER REVIEW 2 of 40 perform sample screening and analysis cycles in the millisecond to picosecond range, necessitating careful consideration of factors such as device design, sensor sensitivity, and material selection. Nanomaterials-based bioNEMS/MEMS have found potential in a myriad of biomedical applications, from drug delivery systems, cell manipulation (e.g., sorting-separation technology and cell patterning) to point-of-care testing (e.g., surgical sensors, implant sensors for tissue engineering applications, and rapid home monitoring devices) [3][4][5][6]. Hence, the development of high-throughput nanomaterials-based bi-oNEMS/MEMS devices is needed.…”

Design, Simulations and Tests of a Novel Force and Moments Sensor for Instrumented Knee Implants

“…However, beyond its complexity of integration, the ageing and brittleness of piezoelectric elements when subjected to shocks still need to be studied, particularly in the context of the knee joint. More recently, [29] repurposed a commercially available tire pressure sensor with the aim of reducing the space allocated to the sensors. Unfortunately, the capacitive pressure transducer, initially dedicated to air pressure measurements, must be coupled to several mechanical interfaces to adapt the high mechanical input force to a micrometer-level deformation.…”