I am not much help at all, but I just wanted to offer my support and hope you find some encouraging answers soon.
A joint mouse is a floating piece of cartilage in the joint.
I have been looking into this product called Lubrisyn. We use it for the horses at our barn, but I noticed there was dosing for dogs as well! It is expensive, but perhaps you could see if that could help with managing your boy's pain.
Janka vom Grunenfeld, BH (d.o.b. 10/12/07)
Last edited by The Stig; 05-16-2014 at 12:15 AM.