High-strength, surface-porous polyether-ether-ketone for load-bearing orthopedic implants. (February 2015)

• Record Type: Journal Article
• Authors: Evans, Nathan T.; Torstrick, F. Brennan; Lee, Christopher S.D.; Dupont, Kenneth M.; Safranski, David L.; Chang, W. Allen; Macedo, Annie E.; Lin, Angela S.P.; Boothby, Jennifer M.; Whittingslow, Daniel C.; Carson, Robert A.; Guldberg, Robert E.; Gall, Ken
• Is Part Of: Acta biomaterialia. Volume 13(2015)
• Page Start: 159
• Page End: 167
• Publication Date: 2015-02
• Subjects: Polyether-ether-ketone (PEEK) -- Fatigue -- Surface porous -- Orthopedic implant; Biomedical materials -- Periodicals; 610.28
• DOI: 10.1016/j.actbio.2014.11.030
• Languages: English
• ISSNs: 1742-7061

Abstract

Graphical abstract: 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.