Adult flatfoot



Flatfoot is a condition in which the arches on the inside of the foot are flattened. When this happens in adults, it’s called adult acquired flatfoot. Over time, this can change the position of your heel and leg bones. It can also lead to knee and ankle problems.

Causes and symptoms

Adult flatfoot is usually caused by years of wear and tear. It happens four times more often in women than it does in men. Diabetes, high blood pressure and being overweight are also factors. It can also happen in just one foot, not both.

There are three stages of adult acquired flatfoot:

  • Stage 1: Inflammation and swelling of the posterior tibial tendon around the inside of the ankle.
  • Stage 2: Noticeable difference when comparing one foot to the other. The foot with problems will become flatter and more deformed.
  • Stage 3: The foot develops a rigid, flat-foot deformity that is painful, primarily on the outside of the ankle.


Your doctor will examine your feet and watch you walk. The affected foot will look different than the unaffected foot. Muscle testing will show less strength. Imaging tests may also be done, including X-rays, CT scans, ultrasounds and MRIs.


Adult acquired flatfoot is best treated early. Treatment depends on how serious the condition is. In Stage 1, wearing a cast and taking medication can help. Wearing well-designed shoes or arch supports can also help keep the foot in the proper position.

If these options don’t help, surgery is the next step. Most flatfoot surgeries require six to twelve weeks of wearing a cast.


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