I have a 12 year old mare, that has had intermittent lameness for approximately six months.  Comes and goes. Super frustrating. Bute, time off, good shoeing, etc. 

Took her to the vet yesterday, xrays are all good (foot, hock and stifle). No bony issues. Ultrasound of  foot tendon,ligaments, soft tissues were normal, but did  show mild increased fluid in the navicular bursa. (bursitis). No reason or cause for this though. 

I asked the vet if it was "navicular syndrome/disease" -- and he told me "NO". Navicular bone is fine. AND navicular disease is usually in the front legs. 

Super confused and frustrated. No concrete diagnosis. Ive been to 3 vets now and no one can give me a definite answer. Except, stall rest, soft footing, anti-inflammatories. 

Anyone have any input or similar situation. I would greatly appreciate input. 

Thanks! 

An MRI would give you a lot of answers if she blocks to her foot. 

For sure. . . MRI was an option presented, just super expensive to have done. I got a quote of $2000 for it. 

Thanks for your time. 

I had one get an acute bursitis in a front foot and the vet injected front Bursa. Might be an option I guess. Only had to do it once thankfuly. 

Yep. I've done it twice on one of mine. wasnt fun on the pocket book.