My horse was diagnosed with navicular several years ago, confirmed by radiographs. Minor lesions noted on both fronts, but mainly the right front. It was a visiting farrier working on someone else's horse that saw her working in the round pen and asked to evaluate her, then recommended she be seen at a lameness clinic.
Once she was diagnosed we took her xrays back to the farrier who looked at her, and he and his partner examined them and discussed treatment with me, which included short-term application of plastic shoes while they adjusted her pastern angles a little.
We had some success getting her back to trail sound, even though he had secondary issues like arthritis due to compensation and is just now recover from major bar malfunction. ("New" farrier gave her incredible relief from the navicular but let other areas of her foot go. I eventually switched trimmers again, and then started learning about trimming myself.)
The current situation is that she is not real sound for anything but toodling around the pasture a little, but I cannot say what the cause is at this time. It could be navicular degeneration, it could be that in an effort to get her bars back under control her heels are now shorter than she is really comfortable with. Her bars are now coming back under control, so I will likely play around with allowing her a little more heel to see how that changes her comfort level. I have not had radiographs done again, and probably will not. She is 21 now, and if trimming practices and a maintenance dose of Previcoxx do not keep her comfortably pasture sound I will put her down.
So, that is our tale. Not sure if there is anything in there for you, but you never know. I am willing to answer questions, feel free.