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Müller P, Synek A, Stauß T, Steinnagel C, Ehlers T, Gembarski PC, Pahr D, Lachmayer R. Development of a density-based topology optimization of homogenized lattice structures for individualized hip endoprostheses and validation using micro-FE. Sci Rep 2024; 14:5719. [PMID: 38459092 PMCID: PMC10923877 DOI: 10.1038/s41598-024-56327-4] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 03/05/2024] [Indexed: 03/10/2024] Open
Abstract
Prosthetic implants, particularly hip endoprostheses, often lead to stress shielding because of a mismatch in compliance between the bone and the implant material, adversely affecting the implant's longevity and effectiveness. Therefore, this work aimed to demonstrate a computationally efficient method for density-based topology optimization of homogenized lattice structures in a patient-specific hip endoprosthesis. Thus, the root mean square error (RMSE) of the stress deviations between the physiological femur model and the optimized total hip arthroplasty (THA) model compared to an unoptimized-THA model could be reduced by 81 % and 66 % in Gruen zone (GZ) 6 and 7. However, the method relies on homogenized finite element (FE) models that only use a simplified representation of the microstructural geometry of the bone and implant. The topology-optimized hip endoprosthesis with graded lattice structures was synthesized using algorithmic design and analyzed in a virtual implanted state using micro-finite element (micro-FE) analysis to validate the optimization method. Homogenized FE and micro-FE models were compared based on averaged von Mises stresses in multiple regions of interest. A strong correlation (CCC > 0.97) was observed, indicating that optimizing homogenized lattice structures yields reliable outcomes. The graded implant was additively manufactured to ensure the topology-optimized result's feasibility.
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Affiliation(s)
- Patrik Müller
- Institute of Product Development, Leibniz University of Hannover, Garbsen, 30823, Germany.
| | - Alexander Synek
- TU Wien, Institute for Lightweight Design and Structural Biomechanics, Vienna, 1060, Austria
| | - Timo Stauß
- Institute of Product Development, Leibniz University of Hannover, Garbsen, 30823, Germany
| | - Carl Steinnagel
- Institute of Product Development, Leibniz University of Hannover, Garbsen, 30823, Germany
| | - Tobias Ehlers
- Institute of Product Development, Leibniz University of Hannover, Garbsen, 30823, Germany
| | | | - Dieter Pahr
- TU Wien, Institute for Lightweight Design and Structural Biomechanics, Vienna, 1060, Austria
- Division Biomechanics, Karl Landsteiner University of Health Sciences, Krems, 3500, Austria
| | - Roland Lachmayer
- Institute of Product Development, Leibniz University of Hannover, Garbsen, 30823, Germany
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