Chaya, Amy
(2016)
Development and Testing of Degradable Magnesium Alloys for Bone Fracture Healing.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Bone fractures are an extremely common injury, with over six million occurring each year in the U.S. Roughly one third of these fractures require internal fixation devices, such as plates and screws, to facilitate bone healing. Traditionally, internal fixation devices have been made with permanent metals like titanium alloys, which can cause long-term complications and even require surgical removal. To circumvent these problems, resorbable polymeric devices have been developed; however their mechanical limitations render them inadequate for many load bearing applications. Unlike permanent metals and resorbable polymers, degradable magnesium alloys provide a balance of degradation and strength. Recent investigations with magnesium alloys have begun demonstrating their promise as orthopedic biomaterials; however, additional work remains to fully assess their efficacy.
For these reasons, we conducted in vivo studies to better understand the biological effects of magnesium degradation. To begin, two subcutaneous implant models were developed incorporating human stem cells and magnesium implants. Using these models, we measured gradual magnesium degradation, and observed human cells and osteogenic protein expression around the implant-tissue interface. These results supported subsequent assessments of magnesium as fixation plates and screws using an ulna fracture model. With pure magnesium devices, we observed gradual implant degradation and fracture healing similar to that of clinically-used titanium devices. In addition, we observed abundant new bone formation around the degrading magnesium devices. Interestingly however, when testing faster degrading magnesium alloy devices, we observed localized cortical bone loss. This dichotomy in observations emphasizes the biological sensitivity to magnesium implants based on their degradation rate and composition. Taken together, our results demonstrate preliminary efficacy of pure magnesium fixation devices and support their continued development; however, additional investigations should be conducted to fully understand the mechanisms of magnesium’s effect on bone biology and long-term safety.
Share
| Citation/Export: |
|
| Social Networking: |
|
Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
|
| Date: |
17 June 2016 |
| Date Type: |
Publication |
| Defense Date: |
18 December 2015 |
| Approval Date: |
17 June 2016 |
| Submission Date: |
22 March 2016 |
| Access Restriction: |
5 year -- Restrict access to University of Pittsburgh for a period of 5 years. |
| Number of Pages: |
140 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Bioengineering |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Magnesium, bone fracture fixation, degradable metal |
| Date Deposited: |
17 Jun 2017 05:00 |
| Last Modified: |
17 Jun 2021 05:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/27304 |
Metrics
Monthly Views for the past 3 years
Plum Analytics
Actions (login required)
 |
View Item |
![[img]](http://d-scholarship.pitt.edu/style/images/fileicons/application_pdf.png)
![[feed]](/images/feed-icon-32x32.png){kind=icon}