A friend of mine had a pony who near the exact same thing happened! It damaged it's rear tendon and had some build up of scar tissue (can't remember if the tissue built up before or after operation, think before!). She travelled hours to go to Newmarket to have this operation, and was then on box rest. After being gradually brought into work again, she can do hacking and schooling. Vet said she would be fine to jump if it was on a good surface, but they don't want to risk it as have another pony to jump with anyway. Hope this helps! Have you got one that needs surgery? =D