Deaeration, pH shift, and surface disruption effects on the corrosion of modular THR alloys

Recent clinical retrieval studies have shown that extensive attack often occurs in modular total hip replacements (THR's). Proposed causes for the degradation of these implants include galvanic, crevice, and fretting corrosion, as well as combinations of these effects. The research described here is part of an ongoing study to determine the mechanism or mechanisms behind these high rates of attack. DC electrochemical techniques have been employed to conduct short, term studies related to device corrosion and fretting. The results suggest that fretting accelerated crevice corrosion is sufficient but not necessary for severe attack of modular THR's. Crevice conditions alone may cause the attack, if the pH and p/sub O2/ levels decline sufficiently far.