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Hall TAG, Theodoridis K, Kohli N, Cegla F, van Arkel RJ. Active osseointegration in an ex vivo porcine bone model. Front Bioeng Biotechnol 2024; 12:1360669. [PMID: 38585711 PMCID: PMC10995341 DOI: 10.3389/fbioe.2024.1360669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 03/08/2024] [Indexed: 04/09/2024] Open
Abstract
Achieving osseointegration is a fundamental requirement for many orthopaedic, oral, and craniofacial implants. Osseointegration typically takes three to 6 months, during which time implants are at risk of loosening. The aim of this study was to investigate whether osseointegration could be actively enhanced by delivering controllable electromechanical stimuli to the periprosthetic bone. First, the osteoconductivity of the implant surface was confirmed using an in vitro culture with murine preosteoblasts. The effects of active treatment on osseointegration were then investigated in a 21-day ex vivo model with freshly harvested cancellous bone cylinders (n = 24; Ø10 mm × 5 mm) from distal porcine femora, with comparisons to specimens treated by a distant ultrasound source and static controls. Cell viability, proliferation and distribution was evident throughout culture. Superior ongrowth of tissue onto the titanium discs during culture was observed in the actively stimulated specimens, with evidence of ten-times increased mineralisation after 7 and 14 days of culture (p < 0.05) and 2.5 times increased expression of osteopontin (p < 0.005), an adhesive protein, at 21 days. Moreover, histological analyses revealed increased bone remodelling at the implant-bone interface in the actively stimulated specimens compared to the passive controls. Active osseointegration is an exciting new approach for accelerating bone growth into and around implants.
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Affiliation(s)
- Thomas A G Hall
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Konstantinos Theodoridis
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Nupur Kohli
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Frederic Cegla
- Non-Destructive Evaluation Group, Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Richard J van Arkel
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, London, United Kingdom
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Hall TAG, Cegla F, van Arkel RJ. Passive Biotelemetric Detection of Tibial Debonding in Wireless Battery-Free Smart Knee Implants. Sensors (Basel) 2024; 24:1696. [PMID: 38475232 DOI: 10.3390/s24051696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 02/23/2024] [Accepted: 02/25/2024] [Indexed: 03/14/2024]
Abstract
Aseptic loosening is the dominant failure mechanism in contemporary knee replacement surgery, but diagnostic techniques are poorly sensitive to the early stages of loosening and poorly specific in delineating aseptic cases from infections. Smart implants have been proposed as a solution, but incorporating components for sensing, powering, processing, and communication increases device cost, size, and risk; hence, minimising onboard instrumentation is desirable. In this study, two wireless, battery-free smart implants were developed that used passive biotelemetry to measure fixation at the implant-cement interface of the tibial components. The sensing system comprised of a piezoelectric transducer and coil, with the transducer affixed to the superior surface of the tibial trays of both partial (PKR) and total knee replacement (TKR) systems. Fixation was measured via pulse-echo responses elicited via a three-coil inductive link. The instrumented systems could detect loss of fixation when the implants were partially debonded (+7.1% PKA, +32.6% TKA, both p < 0.001) and fully debonded in situ (+6.3% PKA, +32.5% TKA, both p < 0.001). Measurements were robust to variations in positioning of the external reader, soft tissue, and the femoral component. With low cost and small form factor, the smart implant concept could be adopted for clinical use, particularly for generating an understanding of uncertain aseptic loosening mechanisms.
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Affiliation(s)
- Thomas A G Hall
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Frederic Cegla
- Non-Destructive Evaluation Group, Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Richard J van Arkel
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, London SW7 2AZ, UK
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Hall TAG, Theodoridis K, Kechagias S, Kohli N, Denonville C, Rørvik PM, Cegla F, van Arkel RJ. Electromechanical and biological evaluations of 0.94Bi 0.5Na 0.5TiO 3-0.06BaTiO 3 as a lead-free piezoceramic for implantable bioelectronics. Biomater Adv 2023; 154:213590. [PMID: 37598437 DOI: 10.1016/j.bioadv.2023.213590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 08/01/2023] [Accepted: 08/13/2023] [Indexed: 08/22/2023]
Abstract
Smart implantable electronic medical devices are being developed to deliver healthcare that is more connected, personalised, and precise. Many of these implantables rely on piezoceramics for sensing, communication, energy autonomy, and biological stimulation, but the piezoceramics with the strongest piezoelectric coefficients are almost exclusively lead-based. In this article, we evaluate the electromechanical and biological characteristics of a lead-free alternative, 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 (BNT-6BT), manufactured via two synthesis routes: the conventional solid-state method (PIC700) and tape casting (TC-BNT-6BT). The BNT-6BT materials exhibited soft piezoelectric properties, with d33 piezoelectric coefficients that were inferior to commonly used PZT (PIC700: 116 pC/N; TC-BNT-6BT: 121 pC/N; PZT-5A: 400 pC/N). The material may be viable as a lead-free substitute for soft PZT where moderate performance losses up to 10 dB are tolerable, such as pressure sensing and pulse-echo measurement. No short-term harmful biological effects of BNT-6BT were detected and the material was conducive to the proliferation of MC3T3-E1 murine preosteoblasts. BNT-6BT could therefore be a viable material for electroactive implants and implantable electronics without the need for hermetic sealing.
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Affiliation(s)
- Thomas A G Hall
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, UK
| | | | - Stylianos Kechagias
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, UK
| | - Nupur Kohli
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, UK; Biomedical Engineering Department, Khalifa University, United Arab Emirates
| | - Christelle Denonville
- Thin Film and Membrane Technology, Sustainable Energy Technology, SINTEF Industry, Norway
| | - Per Martin Rørvik
- Thin Film and Membrane Technology, Sustainable Energy Technology, SINTEF Industry, Norway
| | - Frederic Cegla
- Non-Destructive Evaluation Group, Department of Mechanical Engineering, Imperial College London, UK
| | - Richard J van Arkel
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, UK.
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Wang J, Hall TAG, Musbahi O, Jones GG, van Arkel RJ. Predicting hip-knee-ankle and femorotibial angles from knee radiographs with deep learning. Knee 2023; 42:281-288. [PMID: 37119601 DOI: 10.1016/j.knee.2023.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 01/25/2023] [Accepted: 03/09/2023] [Indexed: 05/01/2023]
Abstract
BACKGROUND Knee alignment affects the development and surgical treatment of knee osteoarthritis. Automating femorotibial angle (FTA) and hip-knee-ankle angle (HKA) measurement from radiographs could improve reliability and save time. Further, if HKA could be predicted from knee-only radiographs then radiation exposure could be reduced and the need for specialist equipment and personnel avoided. The aim of this research was to assess if deep learning methods could predict FTA and HKA angle from posteroanterior (PA) knee radiographs. METHODS Convolutional neural networks with densely connected final layers were trained to analyse PA knee radiographs from the Osteoarthritis Initiative (OAI) database. The FTA dataset with 6149 radiographs and HKA dataset with 2351 radiographs were split into training, validation, and test datasets in a 70:15:15 ratio. Separate models were developed for the prediction of FTA and HKA and their accuracy was quantified using mean squared error as loss function. Heat maps were used to identify the anatomical features within each image that most contributed to the predicted angles. RESULTS High accuracy was achieved for both FTA (mean absolute error 0.8°) and HKA (mean absolute error 1.7°). Heat maps for both models were concentrated on the knee anatomy and could prove a valuable tool for assessing prediction reliability in clinical application. CONCLUSION Deep learning techniques enable fast, reliable and accurate predictions of both FTA and HKA from plain knee radiographs and could lead to cost savings for healthcare providers and reduced radiation exposure for patients.
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Affiliation(s)
- Jinhong Wang
- Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Thomas A G Hall
- Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Omar Musbahi
- Department of Surgery and Cancer, Imperial College London, White City Campus, London W12 0BZ, United Kingdom
| | - Gareth G Jones
- Department of Surgery and Cancer, Imperial College London, White City Campus, London W12 0BZ, United Kingdom
| | - Richard J van Arkel
- Department of Mechanical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom.
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Kohli N, Theodoridis K, Hall TAG, Sanz-Pena I, Gaboriau DCA, van Arkel RJ. Bioreactor analyses of tissue ingrowth, ongrowth and remodelling around implants: An alternative to live animal testing. Front Bioeng Biotechnol 2023; 11:1054391. [PMID: 36890911 PMCID: PMC9986429 DOI: 10.3389/fbioe.2023.1054391] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 02/06/2023] [Indexed: 02/22/2023] Open
Abstract
Introduction: Preclinical assessment of bone remodelling onto, into or around novel implant technologies is underpinned by a large live animal testing burden. The aim of this study was to explore whether a lab-based bioreactor model could provide similar insight. Method: Twelve ex vivo trabecular bone cylinders were extracted from porcine femora and were implanted with additively manufactured stochastic porous titanium implants. Half were cultured dynamically, in a bioreactor with continuous fluid flow and daily cyclic loading, and half in static well plates. Tissue ongrowth, ingrowth and remodelling around the implants were evaluated with imaging and mechanical testing. Results: For both culture conditions, scanning electron microscopy (SEM) revealed bone ongrowth; widefield, backscatter SEM, micro computed tomography scanning, and histology revealed mineralisation inside the implant pores; and histology revealed woven bone formation and bone resorption around the implant. The imaging evidence of this tissue ongrowth, ingrowth and remodelling around the implant was greater for the dynamically cultured samples, and the mechanical testing revealed that the dynamically cultured samples had approximately three times greater push-through fixation strength (p < 0.05). Discussion: Ex vivo bone models enable the analysis of tissue remodelling onto, into and around porous implants in the lab. While static culture conditions exhibited some characteristics of bony adaptation to implantation, simulating physiological conditions with a bioreactor led to an accelerated response.
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Affiliation(s)
- Nupur Kohli
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Konstantinos Theodoridis
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Thomas A G Hall
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Inigo Sanz-Pena
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - David C A Gaboriau
- FILM, National Heart & Lung Institute, Imperial College London, London, United Kingdom
| | - Richard J van Arkel
- Biomechanics Group, Department of Mechanical Engineering, Imperial College London, London, United Kingdom
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Hall TAG, Cegla F, van Arkel RJ. Simple Smart Implants: Simultaneous Monitoring of Loosening and Temperature in Orthopaedics With an Embedded Ultrasound Transducer. IEEE Trans Biomed Circuits Syst 2021; 15:102-110. [PMID: 33471767 DOI: 10.1109/tbcas.2021.3052970] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Implant failure can have devastating consequences on patient outcomes following joint replacement. Time to diagnosis affects subsequent treatment success, but current diagnostics do not give early warning and lack accuracy. This research proposes an embedded ultrasound system to monitor implant fixation and temperature - a potential indicator of infection. Requiring only two implanted components: a piezoelectric transducer and a coil, pulse-echo responses are elicited via a three-coil inductive link. This passive system avoids the need for batteries, energy harvesters, and microprocessors, resulting in minimal changes to existing implant architecture. Proof-of-concept was demonstrated in vitro for a titanium plate cemented into synthetic bone, using a small embedded coil with 10 mm diameter. Gross loosening - simulated by completely debonding the implant-cement interface - was detectable with 95% confidence at up to 12 mm implantation depth. Temperature was calibrated with root mean square error of 0.19°C at 5 mm, with measurements accurate to ±1°C with 95% confidence up to 6 mm implantation depth. These data demonstrate that with only a transducer and coil implanted, it is possible to measure fixation and temperature simultaneously. This simple smart implant approach minimises the need to modify well-established implant designs, and hence could enable mass-market adoption.
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Masen MA, Chung A, Dawczyk JU, Dunning Z, Edwards L, Guyott C, Hall TAG, Januszewski RC, Jiang S, Jobanputra RD, Karunaseelan KJ, Kalogeropoulos N, Lima MR, Mancero Castillo CS, Mohammed IK, Murali M, Paszkiewicz FP, Plotczyk M, Pruncu CI, Rodgers E, Russell F, Silversides R, Stoddart JC, Tan Z, Uribe D, Yap KK, Zhou X, Vaidyanathan R. Evaluating lubricant performance to reduce COVID-19 PPE-related skin injury. PLoS One 2020; 15:e0239363. [PMID: 32970710 PMCID: PMC7514078 DOI: 10.1371/journal.pone.0239363] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 09/07/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Healthcare workers around the world are experiencing skin injury due to the extended use of personal protective equipment (PPE) during the COVID-19 pandemic. These injuries are the result of high shear stresses acting on the skin, caused by friction with the PPE. This study aims to provide a practical lubricating solution for frontline medical staff working a 4+ hours shift wearing PPE. METHODS A literature review into skin friction and skin lubrication was conducted to identify products and substances that can reduce friction. We evaluated the lubricating performance of commercially available products in vivo using a custom-built tribometer. FINDINGS Most lubricants provide a strong initial friction reduction, but only few products provide lubrication that lasts for four hours. The response of skin to friction is a complex interplay between the lubricating properties and durability of the film deposited on the surface and the response of skin to the lubricating substance, which include epidermal absorption, occlusion, and water retention. INTERPRETATION Talcum powder, a petrolatum-lanolin mixture, and a coconut oil-cocoa butter-beeswax mixture showed excellent long-lasting low friction. Moisturising the skin results in excessive friction, and the use of products that are aimed at 'moisturising without leaving a non-greasy feel' should be prevented. Most investigated dressings also demonstrate excellent performance.
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Affiliation(s)
- Marc A. Masen
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Aaron Chung
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Joanna U. Dawczyk
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Zach Dunning
- Department of Manufacturing Engineering, Coventry University, Coventry, United Kingdom
| | - Lydia Edwards
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Christopher Guyott
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Thomas A. G. Hall
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Rachel C. Januszewski
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Shaoli Jiang
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
- Wuhan University of Technology, Wuhan, China
| | - Rikeen D. Jobanputra
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | | | | | - Maria R. Lima
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | | | - Idris K. Mohammed
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Manoj Murali
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Filip P. Paszkiewicz
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Magdalena Plotczyk
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Catalin I. Pruncu
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Euan Rodgers
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Felix Russell
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Richard Silversides
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Jennifer C. Stoddart
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Zhengchu Tan
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - David Uribe
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Kian K. Yap
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
| | - Xue Zhou
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
- Southwest Jiaotong University, Chengdu, China
| | - Ravi Vaidyanathan
- Department of Mechanical Engineering, Imperial College London, London, United Kingdom
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