Implantable electronics for orthopaedic surgery: smart interventions for aseptic loosening and periprosthetic joint infection
File(s)
Author(s)
Hall, Thomas
Type
Thesis
Abstract
Implantable electronics are a key pillar of the ongoing revolution in healthcare towards precision medicine. In orthopaedics, commercial interest in the technology is high but translation has been impeded by inflated device architectures, which are incompatible with the clinical requirement for less invasive implants. In this research, minimalist principles were adopted by which processing and power were externalised to reduce footprint. As demonstrations, two smart implant concepts were developed to mitigate the most severe consequences of aseptic loosening and periprosthetic joint infection, the two most common causes of implant failure, by enabling early diagnosis and intervention. The first concept was a battery-free smart implant with an embedded ultrasound transducer: passive interrogation of the implant was used to extract fixation and temperature data. Fixation was robustly detected in two commercial implants amidst variation in reader and implant positioning, whilst temperature was measured to ±1 °C as a proxy for infection with positioning controls. The second concept delivered controllable electromechanical stimuli to promote osseointegration. In an ex vivo organ model, expansive mineralised structures with high cell viability were observed on the implant surfaces of treated specimens, whilst passive controls exhibited near-zero proliferation or matrix deposition. Both concepts contained lead-based piezoelectric transducers as principal components, and a new lead free piezoceramic (BNT-6BT) was evaluated for comparison. No cytotoxic effect was detected and its surface conducive to cell proliferation, indicating that the piezoceramic could be exposed to – or even integrated with - biological tissue whilst part of a smart implant...
Version
Open Access
Date Issued
2022-09-22
Date Awarded
01/03/2023
Advisor
van Arkel, Richard
Cegla, Frederic
Sponsor
Engineering and Physical Sciences Research Council
Grant Number
2067578
Publisher Department
Mechanical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)