I'm going through fusing hocks with my mare right now. Had her x-rayed earlier this month and my vet suggested pain management (previcox), lots of turn out and 30-45 minutes of light riding a day.
On the previcox (tiny oral pill) she was like a new horse after about three days. She went from an obvious lame trot and at its worst bunny hopping lope (while in her paddock, I didn't ask her to work at all as she was obviously sore) to moving almost totally normal, cocking either hind leg while at rest (before she would only cock her fusing leg) and standing square again.
I started light riding after the 5th day (walk only, 30 mins). It's only been three weeks since starting treatment, but it is working out really well for us so far.