title: PHB, crystalline and amorphous magnesium alloys: promising candidates for bioresorbable osteosynthesis implants?
abstract: In this study various biodegradable materials were tested for their suitability for use in osteosynthesis implants, in particular as elastically stable intramedullary nails for fracture treatment in paediatric orthopaedics. The materials investigated comprise polyhydroxybutyrate (PHB), which belongs to the polyester family and is produced by microorganisms, with additions of ZrO2 and a bone graft substitute; two crystalline magnesium alloys with significantly different degradation rates ZX50 (MgZnCa, fast) and WZ21 (MgYZnCa, slow); and MgZnCa bulk metallic glasses (BMG). Push-out tests were conducted after various implantation times in rat femur meta-diaphysis to evaluate the shear forces between the implant material and the bone. The most promising materials are WZ21 and BMG, which exhibit high shear forces and push-out energies. The degradation rate of ZX50 is too fast and thus the alloy does not maintain its mechanical stability long enough during the fracture-healing period. PHB exhibits insufficient mechanical properties: it degrades very slowly and the respective low shear forces and push-out energy levels are unsatisfactory.
authors.affiliation: Institute for Building Construction and Technology E-206-4, Vienna University of Technology, Karlsplatz 13, 1040 Vienna, Austria.
authors.forename: Anna
authors.initials: A
authors.lastname: Celarek
authors.affiliation: Department of Paediatric Orthopaedics, Medical University of Graz, Auenbruggerplatz 34, 8036 Graz, Austria.
authors.forename: Tanja
authors.initials: T
authors.lastname: Kraus
authors.affiliation: Institute for Building Construction and Technology E-206-4, Vienna University of Technology, Karlsplatz 13, 1040 Vienna, Austria.
authors.forename: Elmar K
authors.initials: EK
authors.lastname: Tschegg
authors.affiliation: Department of Paediatric and Adolescent Surgery, Medical University of Graz, Auenbruggerplatz 34, 8036 Graz, Austria.
authors.forename: Stefan F
authors.initials: SF
authors.lastname: Fischerauer
authors.affiliation: Department of Material Sciences and Process Engineering, Institute of Physics and Materials Science, University of Natural Resources and Life Sciences, Peter Jordan Str. 82, 1190 Vienna, Austria.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Stanzl-Tschegg
authors.affiliation: Department of Materials, Laboratory for Metal Physics and Technology, ETH Zurich, 8093 Zurich, Switzerland.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Uggowitzer
authors.affiliation: Department of Paediatric and Adolescent Surgery, Medical University of Graz, Auenbruggerplatz 34, 8036 Graz, Austria.
authors.forename: Annelie M
authors.initials: AM
authors.lastname: Weinberg
mesh_terms: D000497:Alloys / Q000737:chemistry*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D001842:Bone and Bones / Q000502:physiology; D005269:Femur / Q000502:physiology; D005593:Fracture Fixation, Internal / Q000379:methods*; D006885:Hydroxybutyrates / Q000737:chemistry*; D008274:Magnesium / Q000737:chemistry*; D008297:Male; D008422:Materials Testing / Q000379:methods; D011091:Polyesters / Q000737:chemistry*; D000091402:Prohibitins; D019736:Prostheses and Implants; D051381:Rats; D017207:Rats, Sprague-Dawley; D015032:Zinc / Q000737:chemistry; D000094122:Polyhydroxybutyrates
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D006885:Hydroxybutyrates; D008274:Magnesium; D011091:Polyesters; D000091402:Prohibitins; D015032:Zinc; C000717332:Phb protein, rat; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates