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What is Posterior Tibial Dysfunction (Acquired Flatfoot)?

When someone loses the function of his or her posterior tibialis tendon (a tendon that passes under the ankle and lifts the arch of your foot), he or she will most likely develop posterior tibial dysfunction. The tendon can tear from injury, can suffer from tendinitis, or can include muscle dysfunction. Once the tendon is damaged, the result will often be a loss of support for the foot's arch and a flat foot deformity. The flat feet are correctable, but if ignored, a permanent deformity may result.

Foot pronation (inward tilting of the ankles and flattening of the arches) is a normal part of walking and running, but when excessive, it can lead to foot, ankle, and knee pain.

Causes of Tibial Dysfunction

A damaged posterior tibial can be caused by trauma, a degenerative tear (simple deterioration over time), muscle dysfunction or tenosynovitis (inflammation of the tendon).

Symptoms of Posterior Tibial Dysfunction

Symptoms associated with posterior tibial dysfunction include pain and swelling at the inner ankle when weight is put on the foot. Patients will also say that their foot rolls in or out. There will also be tenderness of the tendon itself. Sometimes patients will hear a pop or click when the foot is moved inward and outward. Patients will usually have trouble walking on their tiptoes, especially if the posterior tibialis tendon is completely torn. In the athletic person, a loud pop associated with pain on the inside of the ankle will alert them to the problem. After a few days they can see that they are becoming flat-footed just on the involved side.

Some physicians will tell patients to have someone stand behind the patient and see if there is a "too many toes" sign. When their feet are viewed from behind, the viewer should only see two toes, but in an affected foot, upwards of four toes will be seen because of the foot's flat appearance and excessive inward pronation.

Also, from behind, physicians will view a patient as he or she stands on his or her tiptoes. A normal foot's heel will slant outward while a foot with posterior tibial dysfunction will remain straight.

Treatment of Posterior Tibial Dysfunction

To reduce inflammation, physicians will recommend a cast or cast boot to be worn for four-to-six weeks. This is most effective when done early in the disease. Other treatments include:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs)
  • A molded ankle-foot orthotics device (foot support)
  • Arch support
  • Keep weight off the foot

In worse case scenarios, surgical reconstruction of the posterior tibialis tendon may be needed.

The information provided herein is not intended to be a substitute for professional medical advice. You should not use this information to diagnose or treat a health problem or disease without consulting a licensed physician.

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