title: High-strength, surface-porous polyether-ether-ketone for load-bearing orthopedic implants.
abstract: Despite its widespread clinical use in load-bearing orthopedic implants, polyether-ether-ketone (PEEK) is often associated with poor osseointegration. In this study, a surface-porous PEEK material (PEEK-SP) was created using a melt extrusion technique. The porous layer was 399.6±63.3 μm thick and possessed a mean pore size of 279.9±31.6 μm, strut spacing of 186.8±55.5 μm, porosity of 67.3±3.1% and interconnectivity of 99.9±0.1%. Monotonic tensile tests showed that PEEK-SP preserved 73.9% of the strength (71.06±2.17 MPa) and 73.4% of the elastic modulus (2.45±0.31 GPa) of as-received, injection-molded PEEK. PEEK-SP further demonstrated a fatigue strength of 60.0 MPa at one million cycles, preserving 73.4% of the fatigue resistance of injection-molded PEEK. Interfacial shear testing showed the pore layer shear strength to be 23.96±2.26 MPa. An osseointegration model in the rat revealed substantial bone formation within the pore layer at 6 and 12 weeks via microcomputed tomography and histological evaluation. Ingrown bone was more closely apposed to the pore wall and fibrous tissue growth was reduced in PEEK-SP when compared to non-porous PEEK controls. These results indicate that PEEK-SP could provide improved osseointegration while maintaining the structural integrity necessary for load-bearing orthopedic applications.
authors.affiliation: School of Materials Science and Engineering, 771 Ferst Drive, J. Erskine Love Building, Georgia Institute of Technology, Atlanta, GA 30332, USA. Electronic address: nevans3@gatech.edu.
authors.forename: Nathan T
authors.initials: NT
authors.lastname: Evans
authors.affiliation: George W. Woodruff School of Mechanical Engineering, 801 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA; Parker H. Petit Institute for Bioengineering and Bioscience, 315 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors.forename: F Brennan
authors.initials: FB
authors.lastname: Torstrick
authors.affiliation: Vertera, Inc., 311 Ferst Drive NW Suite L1328, Atlanta, GA 30332, USA.
authors.forename: Christopher S D
authors.initials: CS
authors.lastname: Lee
authors.affiliation: MedShape, Inc., 1575 Northside Drive, NW, Suite 440, Atlanta, GA 30318, USA.
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Dupont
authors.affiliation: MedShape, Inc., 1575 Northside Drive, NW, Suite 440, Atlanta, GA 30318, USA.
authors.forename: David L
authors.initials: DL
authors.lastname: Safranski
authors.affiliation: Vertera, Inc., 311 Ferst Drive NW Suite L1328, Atlanta, GA 30332, USA.
authors.forename: W Allen
authors.initials: WA
authors.lastname: Chang
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, 313 Ferst Drive, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA.
authors.forename: Annie E
authors.initials: AE
authors.lastname: Macedo
authors.affiliation: George W. Woodruff School of Mechanical Engineering, 801 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA; Parker H. Petit Institute for Bioengineering and Bioscience, 315 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors.forename: Angela S P
authors.initials: AS
authors.lastname: Lin
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, 313 Ferst Drive, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Boothby
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, 313 Ferst Drive, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA.
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Whittingslow
authors.affiliation: George W. Woodruff School of Mechanical Engineering, 801 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Carson
authors.affiliation: George W. Woodruff School of Mechanical Engineering, 801 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA; Parker H. Petit Institute for Bioengineering and Bioscience, 315 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Guldberg
authors.affiliation: School of Materials Science and Engineering, 771 Ferst Drive, J. Erskine Love Building, Georgia Institute of Technology, Atlanta, GA 30332, USA; George W. Woodruff School of Mechanical Engineering, 801 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA; Parker H. Petit Institute for Bioengineering and Bioscience, 315 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors.forename: Ken
authors.initials: K
authors.lastname: Gall
mesh_terms: D000818:Animals; D001577:Benzophenones; D018786:Bone Substitutes / Q000737:chemistry / Q000494:pharmacology; D055119:Elastic Modulus; D005260:Female; D005269:Femur / Q000293:injuries / Q000378:metabolism / Q000473:pathology; D007659:Ketones / Q000737:chemistry / Q000494:pharmacology; D019637:Orthopedic Procedures; D016348:Osseointegration / Q000187:drug effects*; D011092:Polyethylene Glycols / Q000737:chemistry / Q000494:pharmacology; D011108:Polymers; D051381:Rats; D017207:Rats, Sprague-Dawley; D016474:Weight-Bearing
chemical_list: D001577:Benzophenones; D018786:Bone Substitutes; D007659:Ketones; D011108:Polymers; C063834:polyetheretherketone; D011092:Polyethylene Glycols
keywords: Fatigue; Orthopedic implant; Polyether-ether-ketone (PEEK); Surface porous