Total Hip Replacement: The Effect of in vivo Corrosion on the Strength of the Taper Connection
Thursday, February 15, 2018
9:00 AM-11:00 AM
BIOMED PhD Research Proposal
Title:
Total Hip Replacement: The Effect of in vivo Corrosion on the Strength of the Taper Connection
Speaker:
Genymphas Higgs, PhD Candidate, School of Biomedical Engineering, Science and Health Systems, Drexel University
Advisor:
Steven M. Kurtz, PhD, Associate Research Professor, School of Biomedical Engineering, Science and Health Systems, Drexel University
Details:
There are over 2.5 million people living in the United States with a hip replacement, and nearly all designs feature a taper connection. Tapers allow surgeons to configure an implant that better addresses individual patient needs, but these junctions may also wear and corrode, resulting in the release of metallic debris into the patient. Not only have these particles been associated with biological reactions such as tissue damage and elevated systemic blood ion levels, but the corrosion process has been identified as a contributor to mechanical taper failure. Recently, there have been a number of independent reports on spontaneous disassembly of the taper junction, resulting in catastrophic failure and requiring revision surgery. These observational studies have speculated that taper corrosion causes material loss that weakens the taper connection and results in failure of the interlock.
This work explores the causal link between taper corrosion and taper interlock failure by using hip replacements that were retrieved from cadaver donors and from revision surgery. The overarching hypothesis is that the strength of the taper interlock in total hip replacements is differentially affected by specific forms of corrosion, which may be quantitatively identified with electrochemistry. A mechanical experimental system was designed to measure the strength of the taper interlock, and a semi-quantitative technique was developed to visually determine corrosion severity at the interface. With the understanding that corrosion is a process underpinned by electron flow and chemical changes to the alloy, impedance spectroscopy is being incorporated to understand how the electrochemical behavior of the taper interface mediates its strength. This characterization will then be leveraged in designing a novel framework to distinguish individual corrosion damage features quantitatively. Identifying the specific corrosion modes that threaten the strength of the interlock is pivotal to future implant design, as efforts to alter the microstructure of alloys during manufacturing may inhibit some corrosion modes, but exacerbate others.
Contact Information
Ken Barbee
215-895-1335
barbee@drexel.edu