A bunion is a bump that forms on the side of the foot, by the big toe. Once thought to be caused by wearing pointed-toed shoes, bunions are now considered, in most cases, to be the result of fallen arches. Fallen arches cause a change in how the feet work and bunions are one of the possible symptoms. This means they can be prevented, if the foot arch is corrected early enough. It also means the bunion could return after surgery, if the cause of the bunion is not addressed. Custom orthotics are one component of an appropriate treatment plan for bunions.