We explored the possibility that wear products of cobalt-chromium alloy
might lead to sensitivity to metal wear products and in turn to loosening
of a component of the prosthesis after total joint replacement. Twenty
patients with sterile, loose McKee-Farrar hip replacements had patch tests
for sensitivity to cobalt, nickel, and chromium. All tests were negative in
all patients. The histological findings from surrounding tissues in
seventeen patients who had reoperation showed no signs of delayed
hypersensitivity. In five patients, lymphokine assays for migration
inhibition factor and blastogenic factor were done. Only one assay was
positive. Our findings do not support the suggestion that hypersensitivity
to metal is a cause of component loosening after McKee-Farrar total hip
replacement.