title: Coating of carbon fiber-reinforced polyetheretherketone implants with titanium to improve bone apposition.
abstract: Carbon fiber-reinforced polyetheretherketone (CF/PEEK) is a thermoplastic composite biomaterial exhibiting properties suitable for load-bearing orthopedic implants. However, the hydrophobic surface of CF/PEEK implants induces the deposition of a peri-implant fibrous tissue capsule preventing bone apposition. However, if bone apposition was improved, the use of CF/PEEK in orthopedics could be increased as it has many advantages compared with metallic implants. In this study, CF/PEEK screws were coated with titanium (Ti) using two different techniques, namely vacuum plasma spraying (VPS) and physical vapor deposition (PVD) with uncoated screws as controls. These coatings were characterized and implanted in a loaded sheep tibia model. In the characterization of the screw surfaces using microscopy techniques, the uncoated screws were seen to have an irregular surface. The PVD coating appeared smooth and consistent, whereas the VPS coating appeared to be a rough coating with some inhomogeneities, which did not cover the entire surface area. Nevertheless, in the ex vivo analysis the VPS-coated screws had a screw removal torque which was statistically greater than uncoated and PVD-coated screws (p ≤ 0.002 for both comparisons). Additionally, the VPS-coated screws had a statistically higher bone contact area than the uncoated screws (p = 0.006), whereas no statistical difference was detected between VPS and PVD coating types (p = 0.11). Thereby illustrating that Ti coating of CF/PEEK screws significantly improve bone apposition and removal torque compared with uncoated CF/PEEK screws.
authors.affiliation: AO Research Institute, Davos, Switzerland. ddevine50@yahoo.co.uk
authors.forename: Declan M
authors.initials: DM
authors.lastname: Devine
authors.forename: Joachim
authors.initials: J
authors.lastname: Hahn
authors.forename: R Geoffery
authors.initials: RG
authors.lastname: Richards
authors.forename: Heiko
authors.initials: H
authors.lastname: Gruner
authors.forename: Ronald
authors.initials: R
authors.lastname: Wieling
authors.forename: Simon G
authors.initials: SG
authors.lastname: Pearce
mesh_terms: D000818:Animals; D001577:Benzophenones; D001863:Bone Screws; D001842:Bone and Bones / Q000187:drug effects*; D002244:Carbon / Q000737:chemistry*; D000077482:Carbon Fiber; D020099:Coated Materials, Biocompatible; D005260:Female; D016268:Internal Fixators; D007659:Ketones / Q000737:chemistry*; D008422:Materials Testing; D011092:Polyethylene Glycols / Q000737:chemistry*; D011108:Polymers; D019736:Prostheses and Implants; D011474:Prosthesis Design; D012756:Sheep; D013499:Surface Properties; D013977:Tibia / Q000473:pathology; D014025:Titanium / Q000737:chemistry*; D019415:Torque; D016474:Weight-Bearing
chemical_list: D001577:Benzophenones; D000077482:Carbon Fiber; D020099:Coated Materials, Biocompatible; D007659:Ketones; D011108:Polymers; C063834:polyetheretherketone; D011092:Polyethylene Glycols; D002244:Carbon; D014025:Titanium