The first sign of ringbone an owner usually sees is lameness. The tissue around the area may be soft and painful. But as the condition becomes chronic, the soft tissue around the joint becomes very firm, very cool, and there's no pain on palpation. In chronic cases, horses might have swelling around the pastern or on top of the coronet band associated with the coffin joint. Diagnosis is based on history of the problem, external appearance, palpation, and radiographs.
Prognosis depends on the severity of the disease.
But it is a degenerative condition, so it will progress. Adequan is a potent inhibitor of some of the degradative enzymes seen in arthritis, so it's probably helpful in slowing the disease process. These agents are most effective early on, prior to a lot of bony changes. Surgery might be effective for high ringbone when medical management fails. The bone fuses, there is no pain, and since that joint does not have a lot of motion, once you fuse it, it becomes one complete bony column.