Is wearing the aircast inflatable stirrup ankle brace suitable for posterior tibial tendonitis? how long should this be worn?

Air casts do nothing: Air casts do virtually nothing. A functional forefoot orthosis balanced to neutral is what will cure the problem. Be sure you do not stand in a mold to make it. You should be reclined and a plaster slipper cast used placing the foot back into neutral position to make it.

Yes: In most cases the aircast brace is appropriate tx for post tib tendonitis. Occasionally a brace that locks the heal itself might be necessary. With the brace, nsaid's, and some rest mild tendonitis should be better in about 3 weeks. Occasionally more aggressive tx is needed with perhaps a cortizone (hydrocortisone) injection or even surgery if the above and pt doesn't help. Good luck!