The willow curve is at least based on something approaching sound science. I can't tell if it's laser based or LED based, though.
I know various laser based treatments for joint issues, including arthritis, tendonitis, etc., are becoming more and more common and are acknowledged to be effective in certain cases. Friend of mine is a DC and uses laser therapy. He treated my tennis elbow a couple of years ago after I was helping him get his Mom's place ready for sale. It actually helped quite a bit.
If the willow curve is LED based.... no clue as to its value, but LED light treatment does seem to be coming into its own for various things. But, I'm having problems tracking down any real studies with associated data.