Had my horses hocks done(bottom 2 joints, both legs) at the end of August, decided to just put Depo Medrol in the joint and Legend IV (systemic) as the ultimate goal was to get the joints to fuse. It didn't make sense to put HA in the joint as that would prolong the cartilage.
He's been in light-medium work since. Ridden 4-5/wk, mostly out on hacks at a trot and canter, some flat work in the ring. Turned out 24/7.
He seemed great for ~2days maybe a week after the procedure, nice bouncy canter, happy to come out of the field. Then he went back to his old self. Now he seems worse than before the injections... very stiff, especially when wet and cold, needs a longer warm up period. Left actually seems worse than right, which is odd. Perhaps the right has finally fused, it was further along than the left. He drags his left hind toe to start and then gradually gets better. Before now, it was usually just mild stiffness and reluctance to really use his hind end, but not obviously lame.
I've done feed through without a whole lot of improvement (including Cosequin ASU), 2 loading doses of Adequan 6mo apart last year(the 1st round seemed to work great, 2nd not so much) and now the joint injections which I decided on after a full lameness exam this summer showing some discomfort in the hocks. I bought a BOT back pad that I use when I groom and tack up to try to alleviate some of the stiffness, it seems to help.
So now what? I tryed talking to the vet about Pentosan, she didn't seem to know anything about it and I provided some literature on it, but seems pretty skeptical about it. I've asked other vets in the area, they seem to be in the same boat... I think the Legend was responsible for the improvement after the injections, but I thought that it has a short "active" period to benefit the horse. Something in the back of my mind tells me that it doesn't make sense to use it long term...
I had my horse's hocks injected and it lasted all of a month before he was back to pre-injection status. Got the vet back out and decided to try the SI the second time around (flexed off on the hocks and stifle, very reactive to pressure over his SI/loins) and that did the trick. That was maybe 8 months ago and we've been able to maintain by work to strengthen the SI and body work to take care of any muscle tightness before it becomes a major issue.