sounds like you need an AFO - ankle foot orthotic - also known as a foot drop brace.

If you are tripping over your foot, then you may have a foot drop. I do not have MS, but the sort of lupus I have has a lot in common with MS really. I have a bilarteral foot drop and wear two AFO's. They really help prevent me from falling over my feet.

You may need to get a referal to an OT (or orthoticist, or whatever they are called - I can't say it let alone spell it).

cheers
raglet