Posterior tibial tendon dysfunction (PTTD) is the inflammation or over stretching of the posterior tibial tendon in the foot. The function of this tendon is to support the arch in the foot and it assist the foot while walking. However, if PTTD is present than the result is often an adult-acquired flatfoot. If this is left untreated, symptoms will continue to get worse. Symptoms of this condition are pain, swelling, flattening of the arch or an inward roll of the ankle. The area may be red, warm, and swollen as well. There are several treatment options available depends your condition.