Little is known about the ideal factor regimen for hemophiliacs nor ho
w treatment should be administered. A prospective multicenter study ev
aluated different dosage regimens and defined orthopedic outcomes, bas
ed on factor consumption and a comparison of prophylaxis with on-deman
d therapy. Praphylaxis led to better outcomes, whether joints were ini
tially normal or previously affected. Factor use was substantially mor
e costly if prophylaxis was used, but a major reduction could be achie
ved if continuous infusion were feasible.