You have flatfeet when the arches on the inside of your feet are flattened, allowing the entire soles of your feet to touch the floor when you stand up.

A common and usually painless condition, flatfeet can occur when the arches don't develop during childhood. In other cases, flatfeet develop after an injury or from the simple wear-and-tear stresses of age.

Flatfeet can sometimes contribute to problems in your ankles and knees because the condition can alter the alignment of your legs. If you aren't having pain, no treatment is usually necessary for flatfeet.

Most people have no signs or symptoms associated with flatfeet. But some people with flatfeet experience foot pain, particularly in the heel or arch area. Pain may worsen with activity. Swelling along the inside of the ankle can also occur.

When to see a doctor

Talk to your doctor if you or your child has foot pain.

A flat foot is normal in infants and toddlers, because the foot's arch hasn't yet developed. Most people's arches develop throughout childhood, but some people never develop arches. This is a normal variation in foot type, and people without arches may or may not have problems.

Some children have flexible flatfoot, in which the arch is visible when the child is sitting or standing on tiptoes, but disappears when the child stands. Most children outgrow flexible flatfoot without problems.

Arches can also fall over time. Years of wear and tear can weaken the tendon that runs along the inside of your ankle and helps support your arch.

Factors that can increase your risk of flatfeet include:

• Obesity
• Injury to your foot or ankle
• Rheumatoid arthritis
• Aging
• Diabetes

To view the mechanics of your feet, your doctor will observe your feet from the front and back and ask you to stand on your toes. He or she might also look at the wear pattern on your shoes.

Imaging tests

If you're having a lot of pain in your feet, your doctor may order tests such as:

• X-rays. A simple X-ray uses a small amount of radiation to produce images of the bones and joints in your feet. It's particularly useful in detecting arthritis.
• CT scan. This test takes X-rays of your foot from different angles and provides much more detail than a standard X-ray.
• Ultrasound. If your doctor suspects an injured tendon, he or she may request this test, which uses sound waves to produce detailed images of soft tissues within the body.
• MRI. Using radio waves and a strong magnet, MRIs provide excellent detail of both hard and soft tissues.

No treatment is necessary for flatfeet if they don't cause pain.

Therapy

If your flatfeet are painful, your doctor might suggest:

• Arch supports (orthotic devices). Over-the-counter arch supports may help relieve the pain caused by flatfeet. Or your doctor might suggest custom-designed arch supports, which are molded to the contours of your feet. Arch supports won't cure flatfeet, but they often reduce symptoms.
• Stretching exercises. Some people with flatfeet also have a shortened Achilles tendon. Exercises to stretch this tendon may help.
• Supportive shoes. A structurally supportive shoe might be more comfortable than sandals or shoes with minimal support.
• Physical therapy. Flatfeet may contribute to overuse injuries in some runners. A physical therapist can do a video analysis of how you run to help you improve your form and technique.

Surgery

Surgery isn't done solely to correct flatfeet. However, you might have surgery for an associated problem, such as a tendon tear or rupture.

If your flatfeet cause you minor pain, you might want to try:

• Rest. Avoid activities that aggravate your condition. Participate in low-impact activities — such as walking, biking or swimming — rather than jumping and running activities.
• Arch supports. Over-the-counter arch supports might increase your comfort.
• Medications. Over-the-counter pain relievers might help.
• Weight loss. Losing weight can reduce stress on your feet.

If your feet cause you significant pain, your family doctor may refer you to a doctor specializing in foot disorders (podiatrist) or sports medicine.

What you can do

Wear your everyday shoes to your appointment so your doctor can look at the wear patterns on the soles. Before the appointment, you might want to write answers to the following questions:

• When did you first notice problems with your feet?
• What other medical problems, if any, do you have?
• Do your parents or siblings have flatfeet?
• Have you ever injured your foot or ankle?
• What medications and supplements do you take regularly?

What to expect from your doctor

Your doctor may ask some of the following questions:

• Where exactly does it hurt?
• How would you describe the pain — dull, sharp, burning?
• Does any specific motion or position ease the pain or worsen it?
• Does the type of shoe you wear affect the pain?
• Can you stand on tiptoe on one foot?
• Have you tried arch supports?
• How does the pain affect your life?