(18) What types of corrosion are observed in hip replacements?

Corrosion in hip replacement
Advantages of modular connections between head, neck and stem can be offset by their failure risk. The interface between the stem and head, in particular, is known to be susceptible to corrosion, which can lead to a severe foreign body reaction and metal poisoning. Pitting and crevice corrosion have been documented, as well as mechanically assisted corrosion [Gilbert et al 2006]. Geometrical analysis of the surfaces of failed cobalt-chrome heads on titanium stems has suggested that joint loading, including high joint friction moments due to poorly lubricated bearings, may initiate corrosion by fretting, followed by material dissolution. In contrast, titanium heads on titanium stems demonstrate oxidation propagating radially from the interface, followed by crumbling. This can lead to neck fracture, but its potential biological consequences are yet to be clarified.

Posted in: Total Hip Replacement