Corrosion Damage in Retrieved CoCrMo/Ti-6Al-4V Modular Junctions in Femoral Revision Total Knee Components

Modularity in revision total knee arthroplasty (TKA) is prevalent; however, corrosion mechanisms at modular junctions in these devices are not well investigated compared to total hip arthroplasty (THA). This retrieval study analyzed corrosion damage on modular junctions of cobalt chromium molybdenum (CoCrMo) alloy femoral components with a boss and titanium aluminum vanadium (Ti-6Al-4V) stem components. It is hypothesized that similar corrosion modes would be found in TKA as in THA, including mechanically assisted and non-mechanically driven corrosion. The collected implants were examined using the Goldberg corrosion score, digital optical microscopy, scanning electron microscopy, and energy-dispersive x-ray spectroscopy. Corrosion modes were analyzed, including etching, pitting, intergranular (interphase) corrosion adjacent to carbides, and fretting scars with titanium transfer on CoCrMo. Ti-6Al-4V exhibited plastic deformation, mechanically assisted crevice corrosion (MACC), and titanium-chromium-molybdenum-rich oxides. These findings suggest that TKA junctions may experience corrosion processes similar to THA, warranting further clinical investigation.