Titanium-Titanium Junctions in the Knee Corrode, Generating Damage Similar to the Hip

BackgroundPrevious studies identified corrosion between the modular tibial components of total knee arthroplasty (TKA) devices. In this study, we investigated the damage modes present in titanium-titanium (Ti-Ti) junctions in the knee. We asked: under typical in vivo cyclic loading conditions, will the same alloy damage modes from TKA devices resemble those documented in the hip?MethodsA total of 50 paired titanium alloy tibial baseplates and stems were collected and semi-quantitatively analyzed using Goldberg corrosion scoring. To characterize damage, a subsection of moderately and severely corroded components was sectioned and imaged using scanning electron and digital optical microscopy.ResultsOf the 100 device components, 95% showed visual evidence of corrosion. The initial contact area between the stem and bore generally occurred 3 mm from the stem taper base. Scanning electron microscopy revealed four damage modes, including oxide film formation, crevice corrosion, selective dissolution, and pitting.ConclusionsEach of the damage modes identified in modular Ti-Ti tibial junctions was previously reported by total hip arthroplasty retrieval studies. Cumulatively, our results suggest that mechanically assisted crevice corrosion promoted this damage in vivo. Previous studies identified corrosion between the modular tibial components of total knee arthroplasty (TKA) devices. In this study, we investigated the damage modes present in titanium-titanium (Ti-Ti) junctions in the knee. We asked: under typical in vivo cyclic loading conditions, will the same alloy damage modes from TKA devices resemble those documented in the hip? A total of 50 paired titanium alloy tibial baseplates and stems were collected and semi-quantitatively analyzed using Goldberg corrosion scoring. To characterize damage, a subsection of moderately and severely corroded components was sectioned and imaged using scanning electron and digital optical microscopy. Of the 100 device components, 95% showed visual evidence of corrosion. The initial contact area between the stem and bore generally occurred 3 mm from the stem taper base. Scanning electron microscopy revealed four damage modes, including oxide film formation, crevice corrosion, selective dissolution, and pitting. Each of the damage modes identified in modular Ti-Ti tibial junctions was previously reported by total hip arthroplasty retrieval studies. Cumulatively, our results suggest that mechanically assisted crevice corrosion promoted this damage in vivo.