Date of Award
8-2025
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Bioengineering
Committee Chair/Advisor
Dr. Jeremy L. Gilbert
Committee Member
Dr. John DesJardins
Committee Member
Dr. Ying Mei
Committee Member
Dr. Jeremy Mercuri
Abstract
Mechanically assisted corrosion and non-mechanically (chemically) driven corrosion in modular junctions of orthopedic implants using cobalt-chromium-molybdenum (CoCrMo) alloys remain clinical concerns and may contribute to implant failure. The underlying corrosion mechanisms are not yet fully understood, leaving a critical research gap. We hypothesized that corrosion in modular junctions may be driven by aggressive local environments, including fretting, metal ion release (cobalt ion, Co2+), low pH and reactive oxygen species (ROS). This dissertation aims to (1) analyze corrosion modes and potential causes in modular junctions; (2) identify chemically driven corrosion modes on CoCrMo alloys using simulated inflammatory modular taper crevice solutions; (3) elucidate single asperity, mechanically assisted nanoscale corrosion in physiological conditions; and (4) characterize in vitro cellular response in simulated in vivo crevice solution. First, retrieval analysis showed that knee replacements exhibit similar corrosion mechanisms to hip replacements, as both show comparable corrosion modes, including etching, fretting, pitting, carbide boundary corrosion, and titanium transfer. Second, the combination of low pH and ROS or Co2+ in physiological solutions reduced the corrosion resistance of CoCrMo alloy, suggesting that the oxide film is less stable and protective compared to neutral pH solutions without inflammatory factors. Third, we developed novel real-time AFM-based nanoscale tribocorrosion analysis methods (e.g., the tribogram), which track the progression of wear to the sub-nanometer scale and identify distinct tribocorrosion mechanisms on fluid-exposed surfaces by analyzing sharp fluctuations in the tribogram, indicating transient repassivation of the oxide film. Then, fluid-exposed CoCrMo surfaces exhibited reduced susceptibility to nanoscale wear compared to tests in air, calling into question the synergy-based tribocorrosion theories, with protein-containing solutions (bovine albumin serum) demonstrating a further increased wear resistance, likely due to a lubricant effect on wear. Finally, pre-osteoblast responses to Co2+ ions vary depending on the presence of ROS and hypoxia-inducible factor-1a (HIF-1a). In conclusion, understanding the crevice environments in modular junctions is crucial for preventing corrosion.
Recommended Citation
Lee, Hwaran, "Crevice Corrosion Mechanisms of CoCrMo Alloys in Orthopedic Implants: Retrieval Analysis, Nano-tribocorrosion and Cellular Responses" (2025). All Dissertations. 4044.
https://open.clemson.edu/all_dissertations/4044
Author ORCID Identifier
0000-0002-5219-2038
Included in
Biomaterials Commons, Biomedical Devices and Instrumentation Commons, Cell Biology Commons, Metallurgy Commons, Other Biomedical Engineering and Bioengineering Commons, Other Cell and Developmental Biology Commons, Other Engineering Commons, Other Materials Science and Engineering Commons