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Functionally stiff lattice structure for bone reconstruction
Thesis (MEng)--Stellenbosch University, 2023.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2023
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| _version_ | 1867613933567737856 |
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| access_status_str | Open Access |
| author | Heynemann, Marli |
| author2 | Van der Merwe, Johan |
| author_browse | Heynemann, Marli Van der Merwe, Johan |
| author_facet | Van der Merwe, Johan Heynemann, Marli |
| author_sort | Heynemann, Marli |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2023. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/127347 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:44:01Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/127347 Functionally stiff lattice structure for bone reconstruction Heynemann, Marli Van der Merwe, Johan Becker, Thorsten Hermann Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. Lattice structure Strains and stresses Bone scaffolding Additive manufacturing UCTD Thesis (MEng)--Stellenbosch University, 2023. ENGLISH SUMMARY: The treatment of segmental bone loss with reconstructive procedures based on bone grafting is associated with the limitation of donor bone availability and complications at the harvest site, introducing a second surgical site on a patient, increased operating times and increased opportunity of infection. Endoprosthesis, used as a bone substitution, is an alternative reconstructive method which reduces the pain experienced after the procedure, operating time and healing period before a patient may resume load-bearing activities. However, unoptimised titanium implants used for bone substitution have higher stiffness properties than the surrounding bone. The incompatibility in stiffness between the implant and the surrounding bone causes stress shielding, which leads to bone resorption at the interface between the implant and the bone. The reduction in bone mass surrounding the implant leads to complications such as implant loosening, bone fractures and possibly implant failure, which leads to further corrective surgeries affecting the patient’s quality of life. This resulted in the investigation of using a lattice structure to reduce the apparent stiffness of an implant to match, or mimic, the stiffness of bone to reduce the stress shielding phenomenon. A body-centred cuboid unit cell was identified and investigated to match the longitudinal and transverse stiffness bone when repeated in a Ti-6Al-4V (ELI) lattice structure. An analytical model was used to design a body-centred cuboid unit cell with an expected longitudinal stiffness of 17.9 GPa and a transverse stiffness of 10.1 GPa, similar to human cortical bone's average longitudinal and transverse stiffness. The stiffness of the lattice structure was verified by performing compression tests on lattice test specimens according to ISO 13314. The measured elastic modulus of the lattice structure was 14.7 GPa in the longitudinal direction and 8.4 GPa in the transverse direction. The average longitudinal stiffness of bone varies between 14 GPa – 21.8 GPa; consequently, the unit cell stiffness could match the longitudinal stiffness of cortical bone. The measured transverse stiffness of the unit cell also falls within the range of the average transverse stiffness of cortical bone between 7.7 GPa and 12.5 GPa. Based on the compression test findings, the proposed lattice structure could mimic the anisotropic stiffness of bone. Therefore, implementing the proposed unit cell in the design of titanium bone substitution implants could reduce the stress shielding phenomenon. This would increase the success rate of titanium endoprostheses and improve a patient’s quality of life by reducing the effects of the complications associated with stress shielding. AFRIKAANSE OPSOMMING: Die behandeling van segmentele beenverlies met rekonstruktiewe prosedures gebaseer op beenoorplanting word geassosieer met die beperking van skenkerbeenbeskikbaarheid en komplikasies by die skenkerplek, die bekendstelling van 'n tweede chirurgiese wond op 'n pasient, verlengde operasietye en verhoogde geleentheid van infeksie. Endoprostese, wat as beenvervanging gebruik word, is 'n alternatiewe rekonstruktiewe metode wat die pyn wat ervaar word na die prosedure, operasietyd en genesingstydperk verminder voordat 'n pasient lasdraende aktiwiteite kan hervat. Ongeoptimaliseerde titanium-implantate wat vir beenvervanging gebruik word, het egter hoer styfheidseienskappe as die omliggende been. Die onversoenbaarheid in styfheid tussen die implantaat en die omliggende been veroorsaak stres-afskerming, wat lei tot beenresorpsie by die raakvlak tussen die implantaat en die been. Die vermindering in beenmassa rondom die inplanting lei tot komplikasies soos loslating van die implantaat, beenfrakture en moontlik inplantaatversaking, wat lei tot verdere korrektiewe operasies wat die pasient se lewenskwaliteit beinvloed. Dit het gelei tot die ondersoek van die gebruik van 'n traliestruktuur om die oenskynlike styfheid van 'n implantaat te verminder om by die styfheid van been te pas, of na te boots, om die spanningafskermverskynsel te verminder. 'n Binnesentrieskubiese eenheidsel is geidentifiseer en ondersoek om by die longitudinale- en dwarsstyfheid van kortikale been na te boots wanneer dit in 'n Ti-6Al-4V (ELI) traliestruktuur herhaal word. 'n Analitiese model is gebruik om 'n binnesentrieskubiese eenheidsel te ontwerp met 'n verwagte longitudinale styfheid van 17.9 GPa en 'n dwarsstyfheid van 10.1 GPa, soortgelyk aan menslike kortikale been se gemiddelde longitudinale en transversale styfheid. Die styfheid van die traliestruktuur is geverifieer deur kompressietoetse op tralietoetsmonsters uit te voer volgens ISO 13314. Die gemete elastiese modulus van die traliestruktuur was 14.7 GPa in die lengterigting en 8.4 GPa in die dwarsrigting. Die gemiddelde longitudinale styfheid van been wissel tussen 14 GPa – 21.8 GPa; gevolglik stem die die lengtestyfheid van die traliestruktuur ooreen met die longitudinale styfheid van kortikale been. Die gemete dwarsstyfheid van die eenheidsel val ook binne die omvang van die gemiddelde dwarsstyfheid van kortikale been tussen 7.7 GPa en 12.5 GPa. Gebaseer op die kompressietoetsbevindinge, kan die voorgestelde traliestruktuur die anisotropiese styfheid van been naboots. Daarom kan die implementering van die voorgestelde eenheidsel in die ontwerp van titaniumbeenvervangingsimplantate die stresafskermingsverskynsel verminder. Dit sal die sukseskoers van titaan-endoprostese verhoog en 'n pasient se lewenskwaliteit verbeter deur die uitwerking van die komplikasies wat met stresbeskerming geassosieer word, te verminder. Masters 2023-03-02T09:34:53Z 2023-05-18T07:17:24Z 2023-03-02T09:34:53Z 2023-05-18T07:17:24Z 2023-03 Thesis http://hdl.handle.net/10019.1/127347 en_ZA Stellenbosch University xiii, 92 pages : illustrations, includes annexures application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Lattice structure Strains and stresses Bone scaffolding Additive manufacturing UCTD Heynemann, Marli Functionally stiff lattice structure for bone reconstruction |
| title | Functionally stiff lattice structure for bone reconstruction |
| title_full | Functionally stiff lattice structure for bone reconstruction |
| title_fullStr | Functionally stiff lattice structure for bone reconstruction |
| title_full_unstemmed | Functionally stiff lattice structure for bone reconstruction |
| title_short | Functionally stiff lattice structure for bone reconstruction |
| title_sort | functionally stiff lattice structure for bone reconstruction |
| topic | Lattice structure Strains and stresses Bone scaffolding Additive manufacturing UCTD |
| url | http://hdl.handle.net/10019.1/127347 |
| work_keys_str_mv | AT heynemannmarli functionallystifflatticestructureforbonereconstruction |