I gave my senior gelding 3 Osphos injections, about 6-9 months apart. The first one was great, the second was was great but caused a mild colic, and then the third caused a ridiculously stiff neck resulting in more vet visits to make sure he was okay and about two weeks before the neck pain resolved. So as well as it worked, I’m not going to do it again.
His trouble areas are hocks, pasterns, and fetlocks. We’ve done 2 steroid injections in each of these (last ones were about 9 months ago) and he continues to do well. Our plan is to try prostride the next time he needs something. I also just put some composite heartbar shoes on his hind feet and that seems to have made him more comfortable, as well.