Adult Acquired Flatfoot: Cause, Symptoms and Treatment

Adult acquired flatfoot deformity (AAFD) is not present at birth and only acquired during adulthood between 40-60 years of age. Usually caused by damage to the posterior tibial tendon, the arch of the foot gradually collapses as the tendon gets inflamed or torn.


There are a few categories of people more likely to develop AAFD – Women over 40, diabetic patients, obese people and patients with hypertension. Such conditions provide a higher risk to overstretch or rupture the posterior tibial tendon, leading to AAFD.

Other causes of AAFD are rheumatoid arthritis, bone fracture or dislocation. These conditions cause the tendon to be weaker and subject to impairment. Those with flatfoot since birth are also more prone to AAFD later in life.


One or more of these symptoms may be experienced depending on the cause of the AAFD.

  • The foot is angled in an awkward position. One way to check is to view from the back of the foot. For a normal foot, only the fourth and fifth toes can be seen from the back. If the big toe can be seen, chances are AAFD has developed.
  • Pain and swelling along the inner side of the foot causing difficulty to tiptoe.
  • Aggravated pain from long periods of standing or walking, or from high intensity physical activities.
  • Pain in the anklebone that feels like arthritis.
  • Numbness and tingling on the top of the foot and in the toes caused by bony bumps developed from old injuries.
  • Diabetic patients may only notice the swelling but not feel any pain due to their impairment of sensation.



Most cases of AAFD can be treated without surgery. If the condition is not improved after nonsurgical treatments, surgery is needed to realign the foot.


  • Shoe modification may help for mild conditions. A shoe insert or customized shoes that give arch support can be easily purchased from stores.
  • Customized braces and foot orthoses are fit tightly around the leg to prevent it from moving in certain angles and correct the alignment of the foot.
  • Physiotherapy helps to strengthen leg muscles and guide foot movements.


Depending on the type and severity of deformity, one or a combination of these procedures might be used if nonsurgical treatments show no improvement.

  • Repairing of the posterior tibial tendon and removing inflammatory tissue.
  • Tendon transfer if the posterior tibial tendon is badly damaged.
  • Bone surgery is done to recreate the arch and realign the bones, which are then held in place with screws and plates.
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