cornuate navicular and the posterior tibial tendon

An image from the MRI, bisection of ankle, view as if from behind me standing:



This could be the source of my problems. The radiologist describes this as "suggestive of a Type III os naviculare". This is an enlarged "medial horn" of the navicular bone (red arrow). The presence of a navicular type 2 or type 3 is a risk factor for posterior tibial tendon problems, as it "leads to a more proximal insertion of the PTT". Thus, "the leverage of the malleolus on the PTT is reduced and therefore the stress on the tendon increases."

http://www.rbrs.org/dbfiles/journalarticle_0220.pdf
http://www.ajronline.org/cgi/content/full/175/3/627