Processing-structure-property relationships of surface porous polymers for orthopaedic applications

dc.contributor.advisor Gall, Ken
dc.contributor.author Evans, Nathan Timothy
dc.contributor.committeeMember Guldberg, Robert E.
dc.contributor.committeeMember McDowell, David L.
dc.contributor.committeeMember Shofner, Meisha L.
dc.contributor.committeeMember Kumar, Satish
dc.contributor.department Materials Science and Engineering
dc.date.accessioned 2016-05-27T13:23:46Z
dc.date.available 2016-05-27T13:23:46Z
dc.date.created 2016-05
dc.date.issued 2016-04-12
dc.date.submitted May 2016
dc.date.updated 2016-05-27T13:23:46Z
dc.description.abstract The use of polymers in orthopaedics is steadily increasing. In some markets, such as spinal fusion and soft tissue anchors, the polymer polyetheretherketone (PEEK) is already the material of choice in the majority of implants. Despite PEEK’s widespread use, it is often associated with poor osseointegration, which can lead to implant loosening and ultimately failure of the device. Many attempts have been explored to improve the osseointegration of PEEK but none have had widespread clinical success. In this dissertation, a novel surface porous structure has been created, where limiting the porosity to the surface maintains adequate mechanical properties for load bearing applications while providing a surface for improved osseointegration. Careful control of the processing parameters resulted in tunable porous microstructures optimized for bone ingrowth: highly interconnected 200-500µm pores with porosity ranging from 60-85% and pore layers from 300-6000µm thick. Mechanical characterization, including monotonic tensile and compression, tensile fatigue, shear, and abrasion tests, were used to probe the effects of the surface porosity on the relevant mechanical properties of the material. In addition, the effect of surface porosity and surface roughness on the mechanical properties of a range of thermoplastics with varying chemistries and crystallinities was explored. This research showed that there is a great disparity in the notch sensitivity of polymers that correlates to the polymers fracture toughness as well as trends in the monotonic stress-strain curve. The results illustrate that care must be taken in the design of polymeric implants, especially when introducing topographical changes to promote osseointegration, in order to ensure they maintain adequate load-bearing capacity. Finally, preliminary in vitro and in vivo data demonstrated the ability of surface porous PEEK (PEEK-SP) to promote osseointegration. Cells grown on PEEK-SP demonstrated enhanced mineralization and differentiation, suggesting the ability of PEEK-SP to facilitate bone ingrowth. The potential of PEEK-SP was further demonstrated by implantation in a rat femoral segmental defect model which demonstrated bone ingrowth and reduced formation of a fibrous capsule.
dc.description.degree Ph.D.
dc.format.mimetype application/pdf
dc.identifier.uri http://hdl.handle.net/1853/55004
dc.language.iso en_US
dc.publisher Georgia Institute of Technology
dc.subject Polyetheretherketone
dc.subject Biomaterials
dc.subject Polymers
dc.subject Porosity
dc.subject Osseointegration
dc.subject Fatigue
dc.subject Strength
dc.title Processing-structure-property relationships of surface porous polymers for orthopaedic applications
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.corporatename School of Materials Science and Engineering
local.contributor.corporatename College of Engineering
relation.isOrgUnitOfPublication 21b5a45b-0b8a-4b69-a36b-6556f8426a35
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
thesis.degree.level Doctoral
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