ex racehorse lameness

Question
Hi, I have a 4 year old ex racehorse who has been off the track for a little over a year. I have had her for 2 months and I am having trouble keeping her sound. When I first got her I had the farrier put shoes on her. The shoes put too much pressure on her souls and made her feet sore. We changed the shoes to ones with no pressure and she got a lot better. But she never seems completely sound. My trainer says that it might have something to do with her being ponied around as a race horse making her stride weird because she seems to work out of it and doesn't seem like she is in any pain. I was wondering how you felt about this issue and how to go about correcting it. Thanks so much for your time I really need your help!

Answer
Hi Amanda,
            I'd like to think I could help you with a simple answer but this is a mystery to me.
The shoes you put on her first may have focussed your attention on her feet when in fact the problem could be anywhere in the foot or leg. I assume you have had her back and joints checked for misalignment?
Bone splints in a knee or fetlock can cause pain/shortstepping but on warming up can be masked.
There is so much to know about your horse before making any recommendations that I can never know without seeing the horse and maybe not even then. I am a layman rather than a vet or professional trainer so be careful with anything I say.
I hope you can find someone close by who has had a similar problem and found a solution.
Good luck and sorry I was not able to help you.
Regards,
Don Boddie
New Zealand.