CORROSION AT THE INTERFACE - A POSSIBLE SOLUTION TO COBALT-CHROME HEADS ON TITANIUM-ALLOY STEMS

The low-wear characteristics of cobalt-chrome femoral heads matched wi th the excellent biocompatibility and low modulus of titanium alloy fe moral stems constitute the preferred combination used by many orthopae dic surgeons performing total hip arthroplasty. The combination of the se materials in a synovial fluid environment, however, has proven to r esult in extensive crevice corrosion and metallosis of the surrounding tissues. This study investigates an alternative to the conventional m ating of dissimilar metals at the head-neck junction. Five cobalt-chro me heads premated with titanium alloy sleeves were investigated by gro ss examination, dissecting microscopy, and scanning electron microscop y. Examination by both gross examination and dissecting microscope rev ealed no signs of corrosion. Scanning electron microscope examination revealed slight crevice corrosion in the only head with a +15-mm neck length.