Posterior tibial tendon dysfunction (PTTD) is the inflammation or overstretching of the posterior tibial tendon in the foot. The key function of the posterior tibial tendon is to support the arch in the foot. The tendon serves as a major supporting structure to assist the foot function while walking - however, if PTTD is present then the result is oftentimes an “adult-acquired flatfoot.”

Generally, adult-acquired flat-foot occurs only in one foot but can be seen in both. This ailment is generally progressive, so if left untreated, the symptoms will continue to get worse. Symptoms generally occur after an activity that requires the use of the tendon such as running, walking, hiking, or climbing stairs.

Symptoms of PTTD will change as the condition worsens but initially include:

• Pain

• Swelling

• Flattening of the arch

• An inward roll of the ankle

When PTTD initially develops, it begins with pain on the inside of the foot and ankle. The area may be red, warm, and swollen, as well. As the arch begins to flatten, there may still be pain on the inside of the foot and ankle, however, the foot and toes begin to turn outward and the ankle rolls inward. As it reaches its advanced stages, the arch continues to flatten and the pain often shifts to the outside of the foot, below the ankle. This indicates that the tendon has deteriorated considerably and arthritis is likely developing in the foot.