Compliant Intramedullary Stems for Joint Reconstruction
The longevity of current joint replacements is limited by aseptic loosening, which is the primary cause of non-infectious failure for hip, knee, and ankle arthroplasty. Aseptic loosening is typically caused either by osteolysis from particulate wear, or by high shear stresses at the bone-implant int...
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| Format: | Article |
| Language: | English |
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IEEE
2024-01-01
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| Series: | IEEE Journal of Translational Engineering in Health and Medicine |
| Subjects: | |
| Online Access: | https://ieeexplore.ieee.org/document/10433175/ |
| _version_ | 1797272717692502016 |
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| author | John A. Mccullough Brandon T. Peterson Alexander M. Upfill-Brown Thomas J. Hardin Jonathan B. Hopkins Nelson F. Soohoo Tyler R. Clites |
| author_facet | John A. Mccullough Brandon T. Peterson Alexander M. Upfill-Brown Thomas J. Hardin Jonathan B. Hopkins Nelson F. Soohoo Tyler R. Clites |
| author_sort | John A. Mccullough |
| collection | DOAJ |
| description | The longevity of current joint replacements is limited by aseptic loosening, which is the primary cause of non-infectious failure for hip, knee, and ankle arthroplasty. Aseptic loosening is typically caused either by osteolysis from particulate wear, or by high shear stresses at the bone-implant interface from over-constraint. Our objective was to demonstrate feasibility of a compliant intramedullary stem that eliminates over-constraint without generating particulate wear. The compliant stem is built around a compliant mechanism that permits rotation about a single axis. We first established several models to understand the relationship between mechanism geometry and implant performance under a given angular displacement and compressive load. We then used a neural network to identify a design space of geometries that would support an expected 100-year fatigue life inside the body. We additively manufactured one representative mechanism for each of three anatomic locations, and evaluated these prototypes on a KR-210 robot. The neural network predicts maximum stress and torsional stiffness with 2.69% and 4.08% error respectively, relative to finite element analysis data. We identified feasible design spaces for all three of the anatomic locations. Simulated peak stresses for the three stem prototypes were below the fatigue limit. Benchtop performance of all three prototypes was within design specifications. Our results demonstrate the feasibility of designing patient- and joint-specific compliant stems that address the root causes of aseptic loosening. Guided by these results, we expect the use of compliant intramedullary stems in joint reconstruction technology to increase implant lifetime. |
| first_indexed | 2024-03-07T14:33:23Z |
| format | Article |
| id | doaj.art-d3dd36d7e393481faae4d0442b800afd |
| institution | Directory Open Access Journal |
| issn | 2168-2372 |
| language | English |
| last_indexed | 2024-03-07T14:33:23Z |
| publishDate | 2024-01-01 |
| publisher | IEEE |
| record_format | Article |
| series | IEEE Journal of Translational Engineering in Health and Medicine |
| spelling | doaj.art-d3dd36d7e393481faae4d0442b800afd2024-03-06T00:00:18ZengIEEEIEEE Journal of Translational Engineering in Health and Medicine2168-23722024-01-011231432710.1109/JTEHM.2024.336530510433175Compliant Intramedullary Stems for Joint ReconstructionJohn A. Mccullough0https://orcid.org/0000-0002-7050-0305Brandon T. Peterson1Alexander M. Upfill-Brown2Thomas J. Hardin3Jonathan B. Hopkins4https://orcid.org/0000-0003-4752-746XNelson F. Soohoo5https://orcid.org/0000-0002-3943-2631Tyler R. Clites6https://orcid.org/0000-0001-7754-4442Department of Mechanical and Aerospace Engineering, University of California Los Angeles, Los Angeles, CA, USADavid Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USADavid Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USAMaterial, Physical, and Chemical Sciences Center, Sandia National Laboratories, Albuquerque, NM, USADepartment of Mechanical and Aerospace Engineering, University of California Los Angeles, Los Angeles, CA, USADavid Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USADepartment of Mechanical and Aerospace Engineering, University of California Los Angeles, Los Angeles, CA, USAThe longevity of current joint replacements is limited by aseptic loosening, which is the primary cause of non-infectious failure for hip, knee, and ankle arthroplasty. Aseptic loosening is typically caused either by osteolysis from particulate wear, or by high shear stresses at the bone-implant interface from over-constraint. Our objective was to demonstrate feasibility of a compliant intramedullary stem that eliminates over-constraint without generating particulate wear. The compliant stem is built around a compliant mechanism that permits rotation about a single axis. We first established several models to understand the relationship between mechanism geometry and implant performance under a given angular displacement and compressive load. We then used a neural network to identify a design space of geometries that would support an expected 100-year fatigue life inside the body. We additively manufactured one representative mechanism for each of three anatomic locations, and evaluated these prototypes on a KR-210 robot. The neural network predicts maximum stress and torsional stiffness with 2.69% and 4.08% error respectively, relative to finite element analysis data. We identified feasible design spaces for all three of the anatomic locations. Simulated peak stresses for the three stem prototypes were below the fatigue limit. Benchtop performance of all three prototypes was within design specifications. Our results demonstrate the feasibility of designing patient- and joint-specific compliant stems that address the root causes of aseptic loosening. Guided by these results, we expect the use of compliant intramedullary stems in joint reconstruction technology to increase implant lifetime.https://ieeexplore.ieee.org/document/10433175/Orthopaedicsaseptic looseningcompliant mechanismsflexureintramedullary stemsjoint replacement |
| spellingShingle | John A. Mccullough Brandon T. Peterson Alexander M. Upfill-Brown Thomas J. Hardin Jonathan B. Hopkins Nelson F. Soohoo Tyler R. Clites Compliant Intramedullary Stems for Joint Reconstruction IEEE Journal of Translational Engineering in Health and Medicine Orthopaedics aseptic loosening compliant mechanisms flexure intramedullary stems joint replacement |
| title | Compliant Intramedullary Stems for Joint Reconstruction |
| title_full | Compliant Intramedullary Stems for Joint Reconstruction |
| title_fullStr | Compliant Intramedullary Stems for Joint Reconstruction |
| title_full_unstemmed | Compliant Intramedullary Stems for Joint Reconstruction |
| title_short | Compliant Intramedullary Stems for Joint Reconstruction |
| title_sort | compliant intramedullary stems for joint reconstruction |
| topic | Orthopaedics aseptic loosening compliant mechanisms flexure intramedullary stems joint replacement |
| url | https://ieeexplore.ieee.org/document/10433175/ |
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