What is adult acquired flatfoot?

Adult acquired flatfoot is a very common condition that affects the feet and ankles of adult males and females. In people with adult acquired flatfoot, the arch of the foot falls or collapses. It can be a painful, sometimes debilitating condition. However, a painful flatfoot can usually be helped with braces or orthotics and other non-surgical treatments.

Adult acquired flatfoot is different than flatfoot in children. Children will usually outgrow flatfoot on their own, often without treatment. In adults, flat feet usually remain permanently flat. Treatment usually addresses the symptoms rather than a cure.

In adults the condition is called "acquired" flatfoot because it affects feet that at one point in time had a normal longitudinal arch. The deformity may worsen over time as one ages.

Who gets adult acquired flatfoot?

Any adult can develop adult acquired flatfoot. The condition is more common in women over the age of 40, however. Pregnant women are also at a higher risk of developing adult acquired flatfeet. Adults with medical conditions including uncontrolled hypertension, diabetes, rheumatoid arthritis and obesity are also at a higher risk.

People who had flat feet as children are at a higher risk of developing adult acquired flatfoot. Also, those with a family history of flatfoot may be more prone to developing the condition.

What causes adult acquired flatfoot?

There is no one cause of flatfoot in adults.

One of the more common causes is posterior tibial tendon dysfunction (PTTD). This condition affects one of the most important tendons in the foot, the posterior tibial tendon. This tendon's main job is to support the arch of your foot as you walk. The tendon runs down the inside of an individual’s lower leg from the calf to the bones on the inside of the foot. If this tendon is injured, torn, or becomes overused and swollen, it can eventually lead the arch to collapse. This is one of the more common causes of adult acquired flatfoot in women, patients with rheumatoid arthritis and overweight individuals. Athletes in sports, such as soccer or basketball, may also damage this tendon, eventually leading to flat feet.

In some cases, adult acquired flatfoot can also be caused by an injury or tear to the ligaments of the foot. An injury to the middle of the foot, called a Lisfranc injury, can cause the foot to become flat. This injury may be very painful. Injuries to the back of the foot and fractures of the bones in the foot can also cause flatfoot to develop.

Another cause of flatfoot is arthritis. Arthritis that attacks and inflames the cartilage in the joints of the foot can cause the foot to lose its arch and flatten.

In people with diabetes, a condition called Charcot foot may cause flatfoot to develop. This condition may also cause the foot to deform. People with diabetes often have less feeling in their feet or neuropathy, so they do not initially notice as their foot collapses. This can lead to a more severe flattening before diagnosis. In turn, this severe collapse can lead to even more serious problems. Bones in the foot may break and disintegrate as the arch collapses. This can eventually lead to a severely deformed foot. Prescription bracing, footwear or surgery may be required.

Sometimes, a person may think he or she has flatfoot because, on standing, the arch flattens. However, if an arch appears while standing on one’s heels or pulling the toes back, one does not have adult acquired flatfoot. This is a condition called "flexible flatfoot," and is not considered a medical problem that needs treatment.

What are the symptoms of adult acquired flatfeet?

Symptoms of adult acquired flatfoot vary depending on the cause of the condition.

If the flatfoot is caused by posterior tibial tendon dysfunction (PTTD), the person may feel pain along the back of the calf to inside the foot where the tendon runs. There may also be swelling around the ankle.

Pain while walking or standing can also be a symptom of adult acquired flatfoot. It may be worse after vigorous exercise, such as running or power walking.

Ankle pain may also be a symptom of flatfoot, as the collapsed arch causes more pressure to be on the ankle bone.

Bony bumps on the top or inside of the foot can also be a symptom of adult acquired flatfoot.

Adults with diabetes who have acquired flatfoot may not be aware of the normal symptoms of pain due to limited sensation in the feet. The first symptom noticed may be a swelling of the feet or a skin sore that will not heal on the foot.

If you have any of the symptoms of adult acquired flatfoot, you should see a doctor, especially if you have complications of diabetes.

Last reviewed by a Cleveland Clinic medical professional on 03/02/2019.

References

  • American Academy of Orthopaedic Surgeons. Adult acquired flatfoot. Accessed 3/4/2019.
  • Lee MS, Vanore JV, Thomas JL, Catanzariti AR, Kogler G, Kravitz SR et al. Diagnosis and treatment of adult flatfoot. J Foot Ankle Surg. 2005 MarApr;44(2):78-113.
  • DeHeer P, Taulman J. A guide to conservative care for adult flatfoot. Podiatry Today. 2011 Jan;24(1).

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