scholarly journals Design Study on Customised Piezoelectric Elements for Energy Harvesting in Total Hip Replacements

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3480
Author(s):  
Hans-E. Lange ◽  
Rainer Bader ◽  
Daniel Kluess
Keyword(s):  
Energy Harvesting ◽  
Power Output ◽  
Piezoelectric Element ◽  
Element Model ◽  
Design Study ◽  
Total Hip ◽  
Total Hip Replacements ◽  
Hip Replacements ◽  
Therapeutic Measures

Energy harvesting is a promising approach to power novel instrumented implants that have passive sensory functions or actuators for therapeutic measures. We recently proposed a new piezoelectric concept for energy harvesting in total hip replacements. The mechanical implant safety and the feasibility of power generation were numerically demonstrated. However, the power output for the chosen piezoelectric element was low. Therefore, we investigated in the present study different geometry variants for an increased power output for in vivo applications. Using the same finite element model, we focused on new, customised piezoelectric element geometries to optimally exploit the available space for integration of the energy harvesting system, while maintaining the mechanical safety of the implant. The result of our iterative design study was an increased power output from 29.8 to 729.9 µW. This amount is sufficient for low-power electronics.

Comparision of Cup Anteversion and Tilt Effects on Dislocation Propensity for Small-Head-Size Total Hip Replacements

2000 ◽  
Author(s):  
Mark E. Nadzadi ◽  
Douglas R. Pedersen ◽  
John J. Callaghan ◽  
Thomas D. Brown
Keyword(s):  
Range Of Motion ◽  
Three Dimensional ◽  
Element Model ◽  
Head Size ◽  
Modular System ◽  
Total Hip ◽  
Total Hip Replacements ◽  
Apparent Stiffness ◽  
Hip Replacements ◽  
Laboratory Examinations

Abstract While dislocation is a leading cause of total hip replacement failure, empirical observations far outnumber systematic laboratory examinations of this phenomenon. A previously validated three-dimensional, non-linear, contact finite element model was used to study how surgical placement affects dislocation propensity. The computational model employed a widely used 22mm modular system, and examined range of motion prior to impingement as well as peak moment developed to resist dislocation under a typical leg-crossing maneuver. Results were compared to a previous study of an otherwise similar 26mm modular head system, using the same formulation. Similar trends occurred. Increasing tilt and/or anteversion increased both the range of motion and the peak resisting moment, while apparent stiffness seemed to be unaffected. Further, impingement range of motion was independent of head size, but peak resisting moment was nearly 25% less for the 22mm head sizes.

Quantification of self-polishing in vivo from explanted metal-on-metal total hip replacements

2011 ◽  
Vol 44 (5) ◽  
pp. 513-516 ◽  
Author(s):  
Thomas J. Joyce ◽  
Harry Grigg ◽  
David J. Langton ◽  
Antoni V.F. Nargol
Keyword(s):  
Total Hip ◽  
Total Hip Replacements ◽  
Metal On Metal ◽  
Hip Replacements

In vivo wear of bilateral total hip replacements: conventional versus crosslinked polyethylene

2005 ◽  
Vol 125 (8) ◽  
pp. 555-557 ◽  
Author(s):  
Christian Heisel ◽  
Mauricio Silva ◽  
Thomas P. Schmalzried
Keyword(s):  
Total Hip ◽  
Total Hip Replacements ◽  
Hip Replacements

In Vivo Polyethylene Wear of Bilateral Total Hip Replacements - Cemented versus Uncemented Modular Sockets

2010 ◽  
Vol 20 (4) ◽  
pp. 447-452 ◽  
Author(s):  
Rebecca J. Kampa ◽  
Andrew Hacker ◽  
Emmett Griffiths ◽  
John W. Rosson
Keyword(s):  
Polyethylene Wear ◽  
Total Hip ◽  
Total Hip Replacements ◽  
Hip Replacements

Long-Term Survival of Stanmore Total Hip Replacements Inserted with Radiolucent Bone Cement

2002 ◽  
Vol 12 (3) ◽  
pp. 274-280
Author(s):  
J.A. Wimhurst ◽  
J.L. Hobby ◽  
C.P. Roberts ◽  
A.N. Gibbs ◽  
L.J. Deliss ◽  
...  
Keyword(s):  
Bone Cement ◽  
In Vivo Studies ◽  
Long Term Results ◽  
Term Survival ◽  
Total Hip ◽  
Total Hip Replacements ◽  
Hip Replacements

Radio-opacifiers in bone cements are an accepted part of every-day practice. They have, however, been shown to be a potential cause of an increase in third body wear and to excite bone resorption in in vitro and in vivo studies. We reviewed the results of 228 consecutive Stanmore total hip replacements performed between 1981 and 1985 in 211 patients. All were inserted with radiolucent bone cement. Information regarding whether the prosthesis had been revised was available for all patients. Seventy-three patients (83 hips) were still alive and 41 patients (44 hips) were sufficiently healthy to attend clinic. Information regarding pain level was obtained from the remaining 32 patients. When revision of the implant was taken as the end-point, there was 95% ten-year survival, 91% fifteen-year survival and 75% eighteen-year survival. These long-term results of Stanmore THRs, performed in a district general hospital, with radiolucent bone cement, compare favourably with the other published series for this implant. We did not find the inability to see the bone cement a particular disadvantage when reviewing radiographs for signs of loosening.

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

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5151
Author(s):  
Hans-E. Lange ◽  
Nils Arbeiter ◽  
Rainer Bader ◽  
Daniel Kluess
Keyword(s):  
Energy Harvesting ◽  
Power Output ◽  
Functional Model ◽  
Piezoelectric Element ◽  
Numerical Data ◽  
External Energy ◽  
Total Hip ◽  
Piezoelectric Energy ◽  
Bone Segment ◽  
Energy Harvesting System

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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