title: Degradation behaviour of LAE442-based plate-screw-systems in an in vitro bone model.
abstract: The use of absorbable implant materials for fixation after bone fracture helps to avoid a second surgery for implant removal and the risks and costs involved. Magnesium (Mg) is well known as a potential metallic material for degradable implants. The aim of the present in vitro study was to evaluate if degradable LAE442-based magnesium plate-screw-systems are suitable candidates for osteosynthesis implants in load-bearing bones. The corrosion behaviour was tested concerning the influence of different surface treatments, coatings and screw torques. Steel plates and screws of the same size served as control. Plates without special treatment screwed on up to a specified torque of 15cNm or 7cNm, NaOH treated plates (15cNm), magnesium fluoride coated plates (15cNm) and steel plates as control (15cNm) were examined in pH-buffered, temperature-controlled SBF solution for two weeks. The experimental results indicate that the LAE442 plates and screws coated with magnesium fluoride revealed a lower hydrogen evolution in SBF solution as well as a lower weight loss and volume decrease in μ-computed tomography (μCT). The nanoindentation and SEM/EDX measurements at several plate areas showed no significant differences. Summarized, the different screw torques did not affect the corrosion behaviour differently. Also the NaOH treatment seemed to have no essential influence on the degradation kinetics. The plates coated with magnesium fluoride showed a decreased corrosion rate. Hence, it is recommended to consider this coating for the next in vivo study.
authors: Small Animal Clinic, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, 30559 Hannover, Germany.
authors: Leonie
authors: L
authors: Wolters
authors: Institute of Continuum Mechanics, Leibniz Universität Hannover, Appelstraße 11, 30167 Hannover, Germany.
authors: Silke
authors: S
authors: Besdo
authors: Small Animal Clinic, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, 30559 Hannover, Germany.
authors: Nina
authors: N
authors: Angrisani
authors: Institute of Continuum Mechanics, Leibniz Universität Hannover, Appelstraße 11, 30167 Hannover, Germany.
authors: Peter
authors: P
authors: Wriggers
authors: Institute of Production Engineering and Machine Tools, Leibniz Universität Hannover, An der Universität 2, 30823 Garbsen, Germany.
authors: Britta
authors: B
authors: Hering
authors: Institute of Materials Science, Leibniz Universität Hannover, An der Universität 2, 30823 Garbsen, Germany.
authors: Jan-Marten
authors: JM
authors: Seitz
authors: Small Animal Clinic, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, 30559 Hannover, Germany. Electronic address: janin.reifenrath@tiho-hannover.de.
authors: Janin
authors: J
authors: Reifenrath
mesh_terms: D020341:Absorbable Implants; D000497:Alloys / Q000378:metabolism*; D000818:Animals; D001860:Bone Plates; D001863:Bone Screws; D001842:Bone and Bones / Q000378:metabolism*; D003343:Corrosion; D005593:Fracture Fixation, Internal / Q000379:methods; D006859:Hydrogen / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism; D011817:Rabbits
chemical_list: D000497:Alloys; D006859:Hydrogen; D008274:Magnesium
keywords: Degradation; In vitro; Magnesium alloy; Nanoindentation; Plate–screw-system; μCT