title: Fracture healing using degradable magnesium fixation plates and screws.
abstract: OBJECTIVE
  Internal bone fixation devices made with permanent metals are associated with numerous long-term complications and may require removal. We hypothesized that fixation devices made with degradable magnesium alloys could provide an ideal combination of strength and degradation, facilitating fracture fixation and healing while eliminating the need for implant removal surgery.
  
  
  METHODS
  Fixation plates and screws were machined from 99.9% pure magnesium and compared with titanium devices in a rabbit ulnar fracture model. Magnesium device degradation and the effect on fracture healing and bone formation were assessed after 4 weeks. Fracture healing with magnesium device fixation was compared with that of titanium devices using qualitative histologic analysis and quantitative histomorphometry.
  
  
  RESULTS
  Micro-computed tomography showed device degradation after 4 weeks in vivo. In addition, 2-dimensional micro-computed tomography slices and histologic staining showed that magnesium degradation did not inhibit fracture healing or bone formation. Histomorphology showed no difference in bone-bridging fractures fixed with magnesium and titanium devices. Interestingly, abundant new bone was formed around magnesium devices, suggesting a connection between magnesium degradation and bone formation.
  
  
  CONCLUSIONS
  Our results show potential for magnesium fixation devices in a loaded fracture environment. Furthermore, these results suggest that magnesium fixation devices may enhance fracture healing by encouraging localized new bone formation.
authors.affiliation: Graduate Student Researcher, Center for Craniofacial Regeneration, Department of Bioengineering, Department of Oral Biology, and McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA.
authors.forename: Amy
authors.initials: A
authors.lastname: Chaya
authors.affiliation: Research Assistant Professor, Center for Craniofacial Regeneration, Department of Oral Biology, and McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA.
authors.forename: Sayuri
authors.initials: S
authors.lastname: Yoshizawa
authors.affiliation: Professor, Center for Craniofacial Regeneration, Department of Oral Biology, and McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA.
authors.forename: Kostas
authors.initials: K
authors.lastname: Verdelis
authors.affiliation: Research Technician, Center for Craniofacial Regeneration and Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Noorani
authors.affiliation: Professor, Center for Craniofacial Regeneration, McGowan Institute for Regenerative Medicine, and Department of Oral and Maxillofacial Surgery, University of Pittsburgh, Pittsburgh, PA.
authors.forename: Bernard J
authors.initials: BJ
authors.lastname: Costello
authors.affiliation: Professor, Center for Craniofacial Regeneration, Department of Bioengineering, Department of Oral Biology, and McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA. Electronic address: csfeir@pitt.edu.
authors.forename: Charles
authors.initials: C
authors.lastname: Sfeir
mesh_terms: D000818:Animals; D001860:Bone Plates; D001863:Bone Screws; D017102:Fracture Healing; D016268:Internal Fixators; D010012:Osteogenesis; D011817:Rabbits; D055114:X-Ray Microtomography