Parametric analysis of electromechanical and fatigue performance of total knee replacement bearing with embedded piezoelectric transducers

Safaei, Mohsen; Meneghini, R. Michael; Anton, Steven R.

doi:10.1088/1361-665x/aa814e

Cited by 17 publications

(16 citation statements)

References 27 publications

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“…The power output was calculated on the basis of the contact force F 33 acting on the piezoelectric end faces, which is therefore presented first. The results of the sensitivity analysis show that the contact force F 33 and the open-circuit voltage V OC were identically influenced; therefore, only the contact force F 33 is presented and shown in Figure A1, Appendix A. The 10% change in the stiffness of the implant or UHWM-PE housing changed the contact force in a range of up to 10%, respectively up to 6%.…”

Section: Results Of Finite Element Analysis: Deformation Loading and Sensitivitymentioning

confidence: 99%

Performance of a Piezoelectric Energy Harvesting System for an Energy-Autonomous Instrumented Total Hip Replacement: Experimental and Numerical Evaluation

et al. 2021

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Instrumented implants can improve the clinical outcome of total hip replacements (THRs). To overcome the drawbacks of external energy supply and batteries, energy harvesting is a promising approach to power energy-autonomous implants. Therefore, we recently presented a new piezoelectric-based energy harvesting concept for THRs. In this study, the performance of the proposed energy harvesting system was numerically and experimentally investigated. First, we numerically reproduced our previous results for the physiologically based loading situation in a simplified setup. Thereafter, this configuration was experimentally realised by the implantation of a functional model of the energy harvesting concept into an artificial bone segment. Additionally, the piezoelectric element alone was investigated to analyse the predictive power of the numerical model. We measured the generated voltage for a load profile for walking and calculated the power output. The maximum power for the directly loaded piezoelectric element and the functional model were 28.6 and 10.2 µW, respectively. Numerically, 72.7 µW was calculated. The curve progressions were qualitatively in good accordance with the numerical data. The deviations were explained by sensitivity analysis and model simplifications, e.g., material data or lower acting force levels by malalignment and differences between virtual and experimental implantation. The findings verify the feasibility of the proposed energy harvesting concept and form the basis for design optimisations with increased power output.

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Section: Results Of Finite Element Analysis: Deformation Loading and Sensitivitymentioning

confidence: 99%

Performance of a Piezoelectric Energy Harvesting System for an Energy-Autonomous Instrumented Total Hip Replacement: Experimental and Numerical Evaluation

et al. 2021

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“…Stack geometries can provide relatively high coupling properties which are optimal for sensing applications. Additionally, the matched impedance of piezoelectric stacks for optimum energy harvesting is on the order of hundreds of k Ω (as opposed to M Ω for similar monolithic transducers), which is appropriate for realistic energy harvesting circuitry [26].…”

Section: Methodsmentioning

confidence: 99%

Force detection, center of pressure tracking, and energy harvesting from a piezoelectric knee implant

Safaei

Meneghini

Anton

2018

Smart Mater. Struct.

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Recent developments in the field of orthopedic materials and procedures have made the total knee replacement (TKR) an option for people who suffer from knee diseases and injuries. One of the ongoing debates in this area involves the correlation of postoperative joint functionality to intraoperative alignment. Due to a lack of in vivo data from the knee joint after surgery, the establishment of a well-quantified alignment method is hindered. In order to obtain information about knee function after the operation, the design of a self-powered instrumented knee implant is proposed in this study. The design consists of a total knee replacement bearing equipped with four piezoelectric transducers distributed in the medial and lateral compartments. The piezoelectric transducers are utilized to measure the total axial force applied on the tibial bearing through the femoral component of the joint, as well as to track the movement in the center of pressure (CoP). In addition, the generated voltage from the piezoelectrics can be harvested and stored to power embedded electronics for further signal conditioning and data transmission purposes. Initially, finite element (FE) analysis is performed on the knee bearing to select the best location of the transducers with regards to sensing the total force and location of the CoP. A series of experimental tests are then performed on a fabricated prototype which aim to investigate the sensing and energy harvesting performance of the device. Piezoelectric force and center of pressure measurements are compared to actual experimental quantities for twelve different relative positions of the femoral component and bearing of the knee implant in order to evaluate the performance of the sensing system. The output voltage of the piezoelectric transducers is measured across a load resistance to determine the optimum extractable power, and then rectified and stored in a capacitor to evaluate the realistic energy harvesting ability of the system. The results show only a small level of error in sensing the force and the location of the CoP. Additionally, a maximum power of 269.1 μW is achieved with a 175 kΩ optimal resistive load, and a 4.9 V constant voltage is stored in a 3.3 mF capacitor after 3333 loading cycles. The sensing and energy harvesting results present the promising potential of this system to be used as an integrated self-powered instrumented knee implant.

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“…Other methods include adding pressure sensing matrixes to either the surface or directly below the surface in the polymer bearing [9,10]. An alternative to these methods that has been shown capable in determining loads is embedding multiple piezoelectric transducers into the polyethylene bearing of the TKR in order to sense load at various locations (see Figure 1 (b) for conceptual sketch) [11]. The benefits of using piezoelectric transducers (hereafter referred to as PZTs based on their composition of lead zirconate titanate) include the ability to determine load magnitude and location as well as performing other functions simultaneously such as energy harvesting and/or structural health monitoring [12].…”

Section: Introductionmentioning

confidence: 99%

Fabrication and selection of surrogate knee implant bearings for experimental evaluation of embedded in-vivo sensors

Ponder

Safaei

Anton

2019

Journal of the Mechanical Behavior of Biomedical Materials

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Total Knee Replacement (TKR) is a common procedure that is gaining importance with the aging American population. Although TKR is common, about 20% of patients report being unhappy with their results. Previous research has pointed to misalignment and loosening as contributing factors to negative outcomes. What is lacking in the field of TKR is a sensory system that can determine the internal loads of the knee in a direct manner. Implant bearings embedded with piezoelectric transducers have already shown promise in providing accurate sensing data. To perform further experimentation, prototype implant bearings that can be accurately and efficiently produced are needed. This work investigates various fabrication processes and possible materials to provide a foundation for developing surrogate biomechanical implants, especially those with integrated smart sensors. In this study, an original knee bearing is scanned and the resulting geometries used to generate prototypes. The prototypes are fabricated using a variety of methods including CNC machining and additive manufacturing. The prototypes are then tested to determine load distribution, active sensor performance, as well as kinematic performance under loading. The results of this study show that FDM printing provides quick and affordable results but is not ideal for rigorous experimentation. SLA printed prototypes are improved in final quality with an increase in fabrication time. Lastly, CNC machined processes are more labor intensive but can provide the best material characteristics. The findings from this study aim to have an impact not only on researchers studying biomedical sensing, but on the field of biomechanical implants.

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Parametric analysis of electromechanical and fatigue performance of total knee replacement bearing with embedded piezoelectric transducers

Cited by 17 publications

References 27 publications

Performance of a Piezoelectric Energy Harvesting System for an Energy-Autonomous Instrumented Total Hip Replacement: Experimental and Numerical Evaluation

Performance of a Piezoelectric Energy Harvesting System for an Energy-Autonomous Instrumented Total Hip Replacement: Experimental and Numerical Evaluation

Force detection, center of pressure tracking, and energy harvesting from a piezoelectric knee implant

Fabrication and selection of surrogate knee implant bearings for experimental evaluation of embedded in-vivo sensors

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