Flat Feet (Pes Planus)

What is pes planus (flat foot)?

Pes planus means having flat feet — or one flat foot — with little-to-no arch in the sole. You may be flat footed from childhood, or your feet may have lost their natural arches due to a medical condition.

Babies are naturally flat footed, but most begin to develop arches when they start walking. If arches never develop, or if they collapse later in life, flat feet can cause pain or other problems with walking.

Why do foot arches matter?

The arches of your feet play an important role in the mechanics of walking upright. This is why they’re unique to human primates. Your arches are made of bones and connective tissues. They:

• Act as a springboard and shock absorber
• Store and release energy as you walk
• Adapt your foot to uneven walking surfaces
• Protect nerves and vessels in the soles of your feet

Are there different types of flat feet (pes planus)?

Some healthcare providers make a distinction between mildly flat feet that don’t cause any issues and the foot deformity they call pes planus. With pes planus, flat arches cause other changes to your foot.

Pes planus means:

• The arch on the inner side of your sole is flattened and appears to touch the ground.
• The flattened arch causes your heel to point outward and your ankle to roll inward.
• Your talus bone, a bone on the inner side of your foot, sticks out.

Providers may classify your flat feet as flexible or rigid (sometimes flat or always flat). Flat feet can also be congenital (due to conditions present at birth) or acquired (something that happens later in life).

Types include:

• Flexible flat foot. Flexible flat feet are the most common type. With this type, you can see arches in your feet when you aren’t standing on them, but they disappear when you stand.
• Rigid flat foot. If you have rigid flat feet, your feet have no arches whether you’re standing or sitting. You may find it difficult to flex your feet up and down or side to side. This type is rare.
• Congenital flat foot. Some babies have a birth defect that prevents their feet from developing arches. Some hereditary connective tissue disorders can make your arches too weak to hold up.
• Acquired flat foot (fallen arches). Also known as progressive collapsing foot deformity, this condition happens in adulthood, or after your feet have developed their natural arches.

What symptoms do flat feet cause?

Flat feet (pes planus) don’t always cause symptoms for everyone. But they can change the way you walk. They can also transfer too much stress to parts of your lower body that aren’t prepared to bear it.

Early symptoms might include:

• Foot pain after walking
• Ankle pain from overpronation
• Shin splints from overcompensating

Over time, you might develop:

• Gait disorders and abnormalities
• Deformities like bunions or hammertoes
• Chronic pain even when you’re not walking

You might begin to feel pain in your:

• Knees
• Hips
• Lower back

You also might be more at risk of secondary conditions like:

• Repetitive strain injuries
• Ankle instability and sprains
• Foot and ankle arthritis

What causes flat feet (pes planus)?

Some flat feet causes are congenital (present at birth). Other causes happen later in life, after your arches have formed normally. This is called progressive collapsing foot deformity, or “fallen arches.”

Congenital causes

Congenital pes planus is due to conditions present at birth. While all babies are flat footed, some won’t ever develop normal arches. The answer to this is in their genes, which determine their physical traits.

Some families just have flatter arches than others. But genes can also cause genetic disorders or defects that affect how your arches form or prevent them from forming. Some of these conditions include:

• Cerebral palsy
• Clubfoot
• Down syndrome
• Ehlers-Danos syndrome
• Joint hypermobility syndrome
• Marfan syndrome
• Osteogenesis imperfecta
• Tarsal coalition

Acquired flat foot (fallen arches) causes

Acquired pes planus happens when your arches fall flat after forming normally. Arch collapse can happen slowly or rapidly. Diseases and injuries can cause them. Some of these conditions include:

• Posterior tibial tendon dysfunction. This is the most common cause. Chronic tendonitis can weaken this important tendon until it breaks down and can no longer support your arch.
• Charcot foot. Diabetes-related nerve damage can lead the breakdown of the bones in your foot and compromise the supporting ligaments. This can lead to arch collapse.
• Arthritis. Degenerative types and inflammatory types of arthritis can cause swelling and deformity in the joints of your feet. This can throw off the architecture of your foot arches.
• Injury. Foot fractures or injuries to your foot ligaments may undermine your arch support. Going too long without walking while you recover from an injury can weaken the supporting muscles.

How do healthcare providers diagnose pes planus?

An orthopedist or podiatrist can recognize pes planus on a physical exam. They’ll observe the shape and position of your foot, how it moves and how you stand and walk on it.

They’ll ask you about your health history and any prior injuries or conditions that may have caused it. They might take images, like a foot X-ray, to confirm pes planus or to look further into the cause.

How do healthcare providers treat flat feet?

Many people won’t need any treatment for flat feet. If you don’t have symptoms, there’s no need to fix them. If flat feet cause you occasional, mild aches and pains, you can treat them conservatively with:

• Over-the-counter (OTC) pain relievers, like NSAIDs or acetaminophen
• Physical therapy exercises that stretch and strengthen your feet
• Orthotic shoe inserts or other walking supports

But flat feet that cause frequent or significant pain or other complications might need additional treatment. Depending on the cause, some people might need surgery to fix the underlying issue.

Can flat feet be fixed?

Sometimes, a mild and recent case of flat feet will correct itself with conservative treatment. In more severe cases, surgery can potentially fix flat feet. But some of the underlying causes are hard to treat.

When you have a chronic disease that contributes to flat feet, like advanced diabetes, arthritis or a connective tissue disease, it’s not always possible to manage it well enough to preserve your arches.

How can I prevent flat feet?

Often, there isn’t anything you can do to prevent flat feet. Staying at a healthy weight may ease pain from flat feet.

Can you live normally with flat feet?

Yes. Many people with flat feet don’t have noticeable symptoms or need treatment. Your healthcare provider may recommend nonsurgical treatments if pes planus causes foot pain or other problems.

Wearing special footwear and adding some exercises to your daily routine can easily become your new normal. But if they aren’t helping, don’t keep quiet. Some types of pes planus can keep getting worse.