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High-strength, surface-porous polyether-ether-ketone for load-bearing orthopedic implants

2014; Elsevier BV; Volume: 13; Linguagem: Inglês

10.1016/j.actbio.2014.11.030

1878-7568

Nathan T. Evans, F. Brennan Torstrick, Christopher S.D. Lee, Kenneth M. Dupont, David L. Safranski, Wei Chang, Annie E. Macedo, Angela Lin, Jennifer M. Boothby, Daniel C. Whittingslow, Robert Carson, Robert E. Guldberg, Ken Gall,

Total Knee Arthroplasty Outcomes

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.