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What Causes Flat Foot?

If you have flat feet, your feet don’t have a normal arch when you’re standing. This can cause pain when you do extensive physical activity.

The condition is referred to as pes planus, or fallen arches. It’s normal in infants and usually disappears by age 2 or 3 as the ligaments and tendons in the foot and leg tighten. But, it can last through adulthood: 25 percent of American adults have this condition. Having flat feet is rarely serious.

In some cases, flat feet are caused by injuries or illness, creating problems with walking, running, or standing for hours.

Types of Flat Feet

Flexible Flat Foot

Flexible flat foot is the most common type. The arches in your feet appear only when you lift them off the ground, and your soles touch the ground fully when you place your feet on the ground.

This type starts in childhood and usually doesn’t cause pain.

Short Achilles Tendon

Your Achilles tendon connects your heel bone to your calf muscle. If it’s too short, you might experience pain when walking and running. This condition causes the heel to lift prematurely when you’re walking or running.

Posterior Tibial Tendon Dysfunction

This type of flat foot is acquired in adulthood when the tendon that connects your calf muscle to the inside of your ankle is injured, swollen, or torn. If your arch doesn’t receive the support it needs, you’ll have pain on the inside of your foot and ankle, as well as on the outside of the ankle. Depending on the cause, you might have the condition in one or both feet.

What Causes Flat Feet?

Flat feet are related to the tissues and bones in your feet and lower legs. The condition is normal in babies and toddlers because it takes time for the tendons to tighten and form an arch. In rare cases, the bones in a child’s feet become fused, causing pain.

If this tightening doesn’t occur fully, it can result in flat feet. As you age or sustain injuries, the tendons in one or both feet may become damaged. The condition is also associated with diseases such as cerebral palsy and muscular dystrophy.

Who Is at Risk?

You’re more likely to have flat feet if the condition runs in your family. If you’re highly athletic and physically active, your risk is higher due to the possibility of foot and ankle injuries. Older people who are prone to falls or physical injury are also more at risk. People with diseases that affect the muscles — for example, cerebral palsy — also have an increased risk. Other risk factors include obesity, hypertension, and diabetes mellitus.

Recognizing the Symptoms

There is no cause for concern if your feet are flat and you have no pain. However, if your feet ache after walking long distances or standing for many hours, flat feet may be the cause. You may also feel pain in your lower legs and ankles. Your feet may feel stiff or numb, have calluses and possibly lean toward each other.

When to See a Podiatrist

If you have foot pain or your feet are causing problems with walking and running, see an orthopedic surgeon, podiatrist, or your regular doctor.

Diagnosing the problem requires a few tests. Your doctor will look for an arch in your feet as you stand on your toes. If an arch exists, you don’t need treatment for flat feet. Your doctor will also look for flexion in your ankle.

If you’re having difficulty flexing your foot or an arch doesn’t appear, your doctor will order more tests, such as a foot X-ray or a scan to examine the bones and tendons in your feet.

Treating Flat Feet

Foot Support

Supporting your feet is usually a first step in treating the condition. Your doctor may recommend that you wear orthotics, which are inserts that go inside your shoes to support your feet.

For children, the doctor may prescribe special shoes or heel cups until the feet are fully formed.

Lifestyle Changes

Reducing pain from flat feet may involve incorporating some changes in your daily routine. For example, your doctor may recommend a diet and exercise program for weight loss to reduce the pressure on your feet. They may recommend not standing or walking for prolonged periods.


Depending on the cause of your condition, you may have sustained pain and inflammation. Your doctor might prescribe medication to reduce the discomfort from these symptoms. Nonsteroidal anti-inflammatory medications can relieve swelling and pain.

Foot Surgery

Surgery may be an option in more serious cases and is usually the last resort. Your orthopedic surgeon may create an arch in your feet, repair tendons, or fuse your bones or joints. If your Achilles tendon is too short, the surgeon can lengthen it to decrease your pain.

What Is the Long-Term Outlook?

Some people find relief from wearing special shoes or shoe supports. Surgery is usually a last resort, but its outcome is usually positive. Surgery complications, though rare, can include infection, poor ankle movement, improperly healing bones, or persistent pain.

Preventing Flat Feet

Flat feet tend to be hereditary and usually can’t be prevented. But, you can prevent the condition from worsening and causing excessive pain by taking precautions such as wearing shoes that fit well and provide the necessary foot support.

Content licensed from:

Written by: Chitra Badii
Medically reviewed on: Feb 01, 2016: William A Morrison, MD

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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