title: Analysis of Carbon Fiber Reinforced PEEK Hinge Mechanism Articulation Components in a Rotating Hinge Knee Design: A Comparison of In Vitro and Retrieval Findings.
abstract: Carbon fiber reinforced poly-ether-ether-ketone (CFR-PEEK) represents a promising alternative material for bushings in total knee replacements, after early clinical failures of polyethylene in this application. The objective of the present study was to evaluate the damage modes and the extent of damage observed on CFR-PEEK hinge mechanism articulation components after in vivo service in a rotating hinge knee (RHK) system and to compare the results with corresponding components subjected to in vitro wear tests. Key question was if there were any similarities or differences between in vivo and in vitro damage characteristics. Twelve retrieved RHK systems after an average of 34.9 months in vivo underwent wear damage analysis with focus on the four integrated CFR-PEEK components and distinction between different damage modes and classification with a scoring system. The analysis included visual examination, scanning electron microscopy, and energy dispersive X-ray spectroscopy, as well as surface roughness and profile measurements. The main wear damage modes were comparable between retrieved and in vitro specimens (n= 3), whereby the size of affected area on the retrieved components showed a higher variation. Overall, the retrieved specimens seemed to be slightly heavier damaged which was probably attributable to the more complex loading and kinematic conditions in vivo.
authors.affiliation: School of Engineering, University of Portsmouth, Portsmouth PO1 3DJ, UK; Aesculap AG, Research & Development, Am Aesculap-Platz, 78532 Tuttlingen, Germany.
authors.forename: Ronja A
authors.identifier: 0000-0002-0624-1978
authors.initials: RA
authors.lastname: Schierjott
authors.affiliation: Department of Orthopaedics, Vienna General Hospital, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.
authors.forename: Alexander
authors.initials: A
authors.lastname: Giurea
authors.affiliation: Department of Traumatology and Orthopaedics, St. Vincenz Hospital, Am Stein 24, 58706 Menden, Germany.
authors.forename: Hans-Joachim
authors.identifier: 0000-0002-4083-7193
authors.initials: HJ
authors.lastname: Neuhaus
authors.affiliation: Aesculap AG, Research & Development, Am Aesculap-Platz, 78532 Tuttlingen, Germany; Department of Orthopaedic Surgery, Physical Medicine & Rehabilitation, Ludwig Maximilians University Munich, Campus Grosshadern, Marchioninistrasse 15, 81377 Munich, Germany.
authors.forename: Jens
authors.identifier: 0000-0001-6581-3238
authors.initials: J
authors.lastname: Schwiesau
authors.affiliation: Aesculap AG, Research & Development, Am Aesculap-Platz, 78532 Tuttlingen, Germany.
authors.forename: Andreas M
authors.initials: AM
authors.lastname: Pfaff
authors.affiliation: Department of Orthopaedic Surgery, Physical Medicine & Rehabilitation, Ludwig Maximilians University Munich, Campus Grosshadern, Marchioninistrasse 15, 81377 Munich, Germany.
authors.forename: Sandra
authors.identifier: 0000-0003-2065-432X
authors.initials: S
authors.lastname: Utzschneider
authors.affiliation: School of Engineering, University of Portsmouth, Portsmouth PO1 3DJ, UK.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Tozzi
authors.affiliation: Aesculap AG, Research & Development, Am Aesculap-Platz, 78532 Tuttlingen, Germany; Department of Orthopaedic Surgery, Physical Medicine & Rehabilitation, Ludwig Maximilians University Munich, Campus Grosshadern, Marchioninistrasse 15, 81377 Munich, Germany.
authors.forename: Thomas M
authors.identifier: 0000-0002-1068-7497
authors.initials: TM
authors.lastname: Grupp
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D001577:Benzophenones; D002244:Carbon / Q000009:adverse effects*; D000077482:Carbon Fiber; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D007659:Ketones / Q000009:adverse effects*; D007720:Knee Prosthesis / Q000009:adverse effects*; D011092:Polyethylene Glycols / Q000009:adverse effects*; D011108:Polymers; D011474:Prosthesis Design / Q000009:adverse effects*; D011475:Prosthesis Failure / Q000009:adverse effects*
chemical_list: D001577:Benzophenones; D000077482:Carbon Fiber; D007659:Ketones; D011108:Polymers; C063834:polyetheretherketone; D011092:Polyethylene Glycols; D002244:Carbon