title: Design and assessment of a wrapped cylindrical Ca-P AZ31 Mg alloy for critical-size ulna defect repair.
abstract: Recently, magnesium has been investigated as a promising bioresorbable orthopedic biomaterial. Its mechanical properties are very similar to natural bone, making it appropriate for load-bearing orthopedic fracture repair applications. However, significant hurdles remain regarding the design of practical implants and methods to control degradation and enhance biocompatibility. Although attempts have been made to hinder magnesium's rapid corrosion via alloying and coating, these studies have used solid monoliths. In an effort to reduce the amount of alloy used for implantation in a shape that mimics cortical bone shape, this study used a thin sheet of Mg AZ31 which was rolled into hollow cylindrical scaffolds. The scaffold was coated with different amounts of Ca-P; this implant demonstrated slowed corrosion in simulated body fluid (SBF) as well as enhanced biocompatibility for mesenchymal stem cells (MSC). In vivo implantation of magnesium alloy scaffold adjacent to the rat femur showed significant biointegration with further deposition of complex Mg-Ca phosphates/carbonates typical of natural bone. Finally, the implant was placed in a critical-size ulna defect in live rabbits, which lead to radiographic union and partial restoration of biomechanical strength in the defect. This study demonstrated that a thin sheet of coated Mg alloy that was spirally wrapped wound be a promising orthopedic biomaterial for bone repair.
authors.affiliation: Department of Chemistry and Biochemistry, Kettering University, Flint, Michigan 48504, USA.
authors.forename: Montserrat Rabago
authors.initials: MR
authors.lastname: Smith
authors.forename: Patrick
authors.initials: P
authors.lastname: Atkinson
authors.forename: Désirée
authors.initials: D
authors.lastname: White
authors.forename: Tyler
authors.initials: T
authors.lastname: Piersma
authors.forename: Gloria
authors.initials: G
authors.lastname: Gutierrez
authors.forename: Gianny
authors.initials: G
authors.lastname: Rossini
authors.forename: Sapna
authors.initials: S
authors.lastname: Desai
authors.forename: Stephen
authors.initials: S
authors.lastname: Wellinghoff
authors.forename: Hui
authors.initials: H
authors.lastname: Yu
authors.forename: Xingguo
authors.initials: X
authors.lastname: Cheng
mesh_terms: D020341:Absorbable Implants; D000497:Alloys; D000818:Animals; D018786:Bone Substitutes; D002130:Calcium Phosphates; D008274:Magnesium; D008297:Male; D008422:Materials Testing; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D014457:Ulna / Q000293:injuries*
chemical_list: D000497:Alloys; D018786:Bone Substitutes; D002130:Calcium Phosphates; C020243:calcium phosphate; D008274:Magnesium