I agree with Dick
Do not go off warfarin without your doctors involvement and that being on warfarin has nothing to do with your sore knee
If you go off warfarin for any time you need to use another anticoagulant (all of which are worse if you ask me).
If you go off anticoagulation therapy you run the risk of a clot. Such a clot could be a nice little warning like a TIA, or it could leave you with a permanent facial slack, loss of speech , loss of vision, loss of use of one side of your body ... all of which could lead to loss of job and a permanent disability.
and for what? The idea that your sore knee is related to something which it in all probability is not related to it?
Like the old ad says: "see your doctor if pain persists"