title: Peri-implant tissue response and biodegradation performance of a Mg-1.0Ca-0.5Sr alloy in rat tibia.
abstract: Biodegradable magnesium (Mg) alloys combine the advantages of traditional metallic implants and biodegradable polymers, having high strength, low density, and a stiffness ideal for bone fracture fixation. A recently developed Mg-Ca-Sr alloy potentially possesses advantageous characteristics over other Mg alloys, such as slower degradation rates and minimal toxicity. In this study, the biocompatibility of this Mg-Ca-Sr alloy was investigated in a rat pin-placement model. Cylindrical pins were inserted in the proximal tibial metaphyses in pre-drilled holes orthogonal to the tibial axis. Implant and bone morphologies were investigated using μCT at 1, 3, and 6 weeks after implant placement. At the same time points, the surrounding tissue was evaluated using H&E, TRAP and Goldner's trichrome staining. Although gas bubbles were observed around the degrading implant at early time points, the bone remained intact with no evidence of microfracture. Principle findings also include new bone formation in the area of the implant, suggesting that the alloy is a promising candidate for biodegradable orthopedic implants.
authors.affiliation: Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611, USA.
authors.forename: Ida S
authors.initials: IS
authors.lastname: Berglund
authors.affiliation: Department of Biomedical Engineering, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Brittany Y
authors.initials: BY
authors.lastname: Jacobs
authors.affiliation: Department of Biomedical Engineering, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Kyle D
authors.initials: KD
authors.lastname: Allen
authors.affiliation: Department of Small Animal Clinical Sciences, Gainesville, FL 32610, USA.
authors.forename: Stanley E
authors.initials: SE
authors.lastname: Kim
authors.affiliation: Department of Small Animal Clinical Sciences, Gainesville, FL 32610, USA; Clinic of Small Animal Surgery, University of Zurich, Switzerland.
authors.forename: Antonio
authors.initials: A
authors.lastname: Pozzi
authors.affiliation: Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611, USA.
authors.forename: Josephine B
authors.initials: JB
authors.lastname: Allen
authors.affiliation: Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611, USA. Electronic address: mmanuel@mse.ufl.edu.
authors.forename: Michele V
authors.initials: MV
authors.lastname: Manuel
mesh_terms: D020341:Absorbable Implants; D000497:Alloys / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism*; D001858:Bone Nails; D002118:Calcium / Q000737:chemistry; D006859:Hydrogen / Q000378:metabolism; D008274:Magnesium / Q000737:chemistry; D008297:Male; D008422:Materials Testing; D051381:Rats; D017207:Rats, Sprague-Dawley; D013324:Strontium / Q000737:chemistry; D013977:Tibia / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D055114:X-Ray Microtomography
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D006859:Hydrogen; D008274:Magnesium; D002118:Calcium; D013324:Strontium
keywords: Biodegradable alloy; Calcium; Magnesium; Rat preclinical model; Strontium