Injectable PSGAG's in the form of Adequan have been used in horses and small animals for years and it appears to be chondroprotective, although the evidence is stronger for IA use versus IM. Stronger is relative, of course - I have yet to find any large-scale trials. So, clinically speaking, it seems to work (and some have been using compounded pentosan polysulfate), but is that enough? Will we ever see this drug cross into the human medicine realm, or is it too nebulous and unsupported for that to happen? Would people even go for an OA treatment that had to be injected regularly? Does OA just not matter for many people because they sit on their butts and don't complain (or pop NSAID's) until it gets so bad the joint is trashed, cartilage eroded, subchondral bone damaged? Maybe I'm sensitized because many people expect their horses to be athletes for much of their lives, so synovitis, etc., is taken seriously and often injected with HA and triamcinolone. Of course, we don't know for sure at what point we are doing more harm than good. What about doxycycline and MMP inhibition? Is that going to go anywhere WRT new drugs for OA treatment? Please speculate. Science is nice but not necessary.