Magnetic boots have been great for mine
Adding turmeric to your horses grain. Turmeric helps with inflammation, started giving my horse turmeric and my body worker said it has been working miracles, he was so more joint pain
Pentosan injections, 4cyte feed supplements or basic supplements like glucosamine HCL and MSM can help :)
Talk to your vet about management practices, and about getting a physio out to have a look. In the mean time, up the oil content of the horse's diet and keep the pony in slow, light exercise.
If he was diagnosed, what did your vet say you should do?
I know that some people use ice on there horse frequently and wrap them with special cream that helps with that at night