title: The biocompatibility of degradable magnesium interference screws: an experimental study with sheep.
abstract: Screws for ligament reconstruction are nowadays mostly made of poly-L-lactide (PLLA). However, magnesium-based biomaterials are gathering increased interest in this research field because of their good mechanical property and osteoanabolic influence on bone metabolism. The aim of this pilot study was to evaluate the biocompatibility of an interference screw for ligament reconstruction made of magnesium alloy W4 by diecasting and milling and using different PEO-coatings with calcium phosphates. PLLA and titanium screws were used as control samples. The screws were implanted in the femur condyle of the hind leg of a merino sheep. The observation period was six and twelve weeks and one year. Histomorphometric, immunohistochemical, immunofluorescence, and molecular biological evaluation were conducted. Further TEM analysis was done. In all magnesium screws a clinically relevant gas formation in the vicinity of the biomaterial was observed. Except for the PLLA and titanium control samples, no screw was fully integrated in the surrounding bone tissue. Regarding the fabrication process, milling seems to produce less gas liberation and has a better influence on bone metabolism than diecasting. Coating by PEO with calcium phosphates could not reduce the initial gas liberation but rather reduced the bone metabolism in the vicinity of the biomaterial.
authors.affiliation: Laboratory for Experimental Trauma Surgery, Justus-Liebig University Giessen, Kerkrader Straße 9, 35394 Giessen, Germany ; Department of Trauma Surgery Giessen, University Hospital of Giessen-Marburg, Justus-Liebig University Giessen, Rudolf-Buchheim-Straße 7, 35392 Giessen, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Thormann
authors.affiliation: Laboratory for Experimental Trauma Surgery, Justus-Liebig University Giessen, Kerkrader Straße 9, 35394 Giessen, Germany ; Department of Trauma Surgery Giessen, University Hospital of Giessen-Marburg, Justus-Liebig University Giessen, Rudolf-Buchheim-Straße 7, 35392 Giessen, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Alt
authors.affiliation: aap Biomaterials GmbH, Lagerstraße 11-15, 64807 Dieburg, Germany.
authors.forename: Lydia
authors.initials: L
authors.lastname: Heimann
authors.affiliation: aap Biomaterials GmbH, Lagerstraße 11-15, 64807 Dieburg, Germany.
authors.forename: Cyrille
authors.initials: C
authors.lastname: Gasquere
authors.affiliation: Laboratory for Experimental Trauma Surgery, Justus-Liebig University Giessen, Kerkrader Straße 9, 35394 Giessen, Germany ; Department of Trauma Surgery Giessen, University Hospital of Giessen-Marburg, Justus-Liebig University Giessen, Rudolf-Buchheim-Straße 7, 35392 Giessen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Heiss
authors.affiliation: Department of Trauma Surgery Giessen, University Hospital of Giessen-Marburg, Justus-Liebig University Giessen, Rudolf-Buchheim-Straße 7, 35392 Giessen, Germany.
authors.forename: Gabor
authors.initials: G
authors.lastname: Szalay
authors.affiliation: Department of Trauma and Orthopedic Surgery, Elbe Kliniken Stade, Bremervörder Straße 111, 21682 Stade, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Franke
authors.affiliation: Laboratory for Experimental Trauma Surgery, Justus-Liebig University Giessen, Kerkrader Straße 9, 35394 Giessen, Germany ; Department of Trauma Surgery Giessen, University Hospital of Giessen-Marburg, Justus-Liebig University Giessen, Rudolf-Buchheim-Straße 7, 35392 Giessen, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Schnettler
authors.affiliation: Laboratory for Experimental Trauma Surgery, Justus-Liebig University Giessen, Kerkrader Straße 9, 35394 Giessen, Germany
authors.forename: Katrin Susanne
authors.initials: KS
authors.lastname: Lips
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology*; D001863:Bone Screws; D019544:Equipment Failure Analysis; D005260:Female; D005269:Femur / Q000473:pathology* / Q000601:surgery*; D008274:Magnesium / Q000494:pharmacology*; D008422:Materials Testing; D011474:Prosthesis Design; D012756:Sheep
chemical_list: D001672:Biocompatible Materials; D008274:Magnesium