Posterior tibial tendon dysfunction (PTTD) is caused by changes in the tendon, causing it to no longer properly support the arch while walking. This results in flattening of the foot.

PTTD or "adult acquired flatfoot” as it is often called, is the most common type of flatfoot developed as an adult. Usually PTTD forms in only one foot but can develop in both. PTTD, if untreated, will continue to worsen.

Causes
The most common cause of PTTD is overuse of the posterior tibial tendon. Symptoms usually present themselves after physical activities that involve the tendon (ex. running, walking, hiking, or climbing stairs)

Symptoms
With PTTD you may experience pain and swelling, a flattening of the arch, and/or an inward rolling of the ankle. In addition, your foot and ankle may be red, warm, and swollen.

As the condition progresses, your symptoms will change. As the arch begins to flatten, there may still be pain on the inside of your foot and ankle. But at this point, your foot and toes begin to turn outward and your ankle rolls inward.

As PTTD becomes more advanced, your arch will flatten even more and the pain may shift to the outside of your foot, below the ankle. By now, your tendon has deteriorated considerably and your chances of getting arthritis in the foot and ankle increase significantly.

Treatment (Non-surgical)
Because PTTD will continue to worsen over time, early treatment is advised. Early treatment can help you avoid the need for surgery as well as keep the condition from getting worse.

If left untreated, PTTD could leave you with an extremely flat foot and painful arthritis in your foot and ankle. This will force increased limitations on walking, running, and other physical activities.

Examples of non-surgical treatment include:

- Orthotic devices or bracing may be prescribed to give your arch the support it needs.
- To allow the tendon to heal, you may need to completely avoid all weight-bearing physical activities for a while. Your doctor may prescribe a short-leg cast or boot to protect the tendon as it heals.
- Following immobilization of the foot and ankle, physical therapy and ultrasound therapy may help rehabilitate the tendon and muscle.
- Medications such as nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, help reduce pain and inflammation.
- Your doctor may advise changes to make with your shoes and may provide special inserts designed to improve arch support.

When Is Surgery Needed?
In severe cases where the PTTD has gone untreated to too long or if non-surgical treatments have failed to correct the issue, surgery may be required. In some cases, surgery may be the only option. Your foot doctor will determine the best approach for you.