bump - I am curious about your question, too.
Trying to make conversation here, so that maybe someone will answer your questions: Can you tell us more about how your horse was diagnosed? What sort of problems did you have that lead to the diagnosis? What was the horse injected with?
On various horses I have had the hocks, coffin joint, stifles on one, and a fetlock injected. My vets have always been very conservative following injections (as have I). With these lower joints, I always keep the elasticon on for 24 hrs during their stall rest. The vet administers IV bute, and I usually bute for 2 days following injections. This is followed by removing the elesticon and small paddock turnout for 3-4 days. The horse is then put lightly back under saddle for a day or two, and then back into full work.
Any time you go into a joint with a needle, there is a risk. Not only is there risk of infection (especially lower joints), but can be very painful for the horse. The last horse that I had injected was this spring, and it was stifles. The vet said that I should see results within two weeks, and full effect within 4-6 weeks. I am happy to say that I saw results within 2 days!
Length of recovery time would depend upon the extent of the injury, and how long the horse was in pain before being treated. The longer the time in pain, the more chance that muscles developed unevenly and improperly. Consistent and even WTC both directions, working the horse from behind and over his back, stretching, encouraging bending right and left WTC will develope a proper topline.
What sort of a rehab program did your vet send you home with? What excercises and how long is the program?