In forty-five patients, who had an arthrodesis because of failed total
knee arthroplasty, the cause was infection in forty, instability in two,
failure of the prosthesis in two, and loosening in one. The arthrodesis
succeeded in twenty-nine (81%) of thirty-six patients who had had a
minimally or partially constrained arthroplasty and in five (56%) of nine
who had had a hinge-type prosthesis inserted. The reasons for failure were
severe bone loss, persistent sepsis, and loss of bone apposition after
manipulation. The technique of arthrodesis did not seem to influence the
final result. External fixation most commonly had to be used because of the
infections and the device was kept in place for an average of ten weeks,
after which immobilization in a cast was used until the arthrodesis
healed.