Yes, I want to know how long a injection of corisone, injected into a Bulls knee, after drained, Arthrithis, in knee injury.: How long does this medicine stay in system? I ts really hard watching him hurt, taking Best care I can, hauling him water, hay, and food . Several times a day, Vet says 50 days, i m almost there, but Prossessing plant says, best to wait one more Week, 100% days and watching this , I don t want wait a another week of Aggavation. Do you think that is plenty of time? Thank You, I ve looked everywhere on this Computor, haven t found my Answer yet.