Amy Chaya1, Sayuri Yoshizawa2, Kostas Verdelis3, Sabrina Noorani4, Bernard J Costello5, Charles Sfeir6. 1. 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. 2. Research Assistant Professor, Center for Craniofacial Regeneration, Department of Oral Biology, and McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA. 3. Professor, Center for Craniofacial Regeneration, Department of Oral Biology, and McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA. 4. Research Technician, Center for Craniofacial Regeneration and Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA. 5. Professor, Center for Craniofacial Regeneration, McGowan Institute for Regenerative Medicine, and Department of Oral and Maxillofacial Surgery, University of Pittsburgh, Pittsburgh, PA. 6. 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.
Abstract
PURPOSE: 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. MATERIALS AND 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. CONCLUSION: 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.
PURPOSE: 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. MATERIALS AND 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. CONCLUSION: 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: Mike Barbeck; Lennart Kühnel; Frank Witte; Jens Pissarek; Clarissa Precht; Xin Xiong; Rumen Krastev; Nils Wegner; Frank Walther; Ole Jung Journal: Int J Mol Sci Date: 2020-04-28 Impact factor: 5.923