Has anyone heard of the treatment called Kush, or CUSH. The proper name is long and I cannot remember it.

Yes - I actually know one of the vets personally that's involved in it. It's similar to Noltrex which I've used in the past with great success. My gelding has an awful knee at 9 years old, visibly lame when he got off the trailer in January, injected and ran him on it extensively and it's still holding. When he needs another injection I'm going to try Kush. I've heard really good things about it.