Subvention doesn't encompass vets' treatment of foot complaint (6)
I believe the answer is:
bunion
'complaint' is the definition.
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for bunion that I've seen before include "Swelling at base of toe with thickened skin" , "Painful swelling of the big toe joint" , "Something painful" , "Painful swelling at base of big toe" , "Foot fault" .)