A Randomized Single Blinded Trial (Landorf et al, 2006) concluded that, long term, both prefabricated and custom orthoses are no more effective in treating Plantar Fasciitis than a sham device. 

In my clinical practice, I have found proprioceptive therapy to be very effective in resolving Plantar Fasciitis when secondary to either the Rothbarts Foot or the PreClinical Clubfoot Deformity. 

References:

   Landorf KB, Keenan AM, Herbert RD 2006. Arch Intern Med. 166:1305-1310.
    Rothbart BA 1971.  Heel spur and heel spur syndrome.  Journal American Podiatric Medical Association(JAPMA), 61(5):186-9.

Plantar Fascittis

Plantar Fasciitis is a common symptom resulting from abnormal foot pronation.

Abnormal foot pronation occurs both the Rothbarts Foot and the PreClinical Clubfoot Deformity.