Behind my left knee & in my calf-I was diagnosed with blood clots last August. I'm on Coumadin. My last INR-two weeks ago was 3.4. I have constant arthritis pain in my RIGHT knee-causing me to limp. I lose sleep-Tylenol ex-strength doesn't help much. I'm doing Physio. I can't take NSAIDs. So I'm contemplating a cortisone shot in the right knee. What are the risks of this affecting the bloodclots behindmy left knee? Will they have the potential to travel? I'm nervous-but tired of the pain.