Flexible Flatfoot in Children

The short version

Most parents who bring a child to see me about flat feet already suspect it is not a big problem. What they want is to hear it from someone who looks at children's feet every day, and to be sure of two things: that it will not hurt their child later, and that they are not missing a window for treatment. Here is what I tell them.

• A flexible flatfoot is common and normal in young children.
• Most of the time the arch appears on its own as the child grows.
• When it does not, a flexible flatfoot is still a normal foot. It does not lead to arthritis or disability.
• There is no treatment that changes the shape of a growing flexible foot, so there is no window to miss.
• A shoe insert can make an older child more comfortable in sports. It is for comfort, not correction. Take it out and the foot is unchanged.
• A short list of foot problems does need a visit: a stiff flatfoot, a painful one, one that is only on one side, or a tight heel cord. Those are at the end of this guide.

What a flexible flatfoot is

Stand your child on the floor and look at the inside edge of each foot. In a flatfoot, the arch that most adults have is low or touches the ground, and from behind, the heel tilts outward so the ankle seems to roll in. Now ask your child to stand on tiptoe, or lift the foot off the floor: the arch appears, and the heel swings back under the leg. That is what "flexible" means. The bones and joints move normally. The arch is there; it just flattens under the child's weight.

Doctors call this flexible pes planovalgus: "planus" for the flat arch and "valgus" for the outward tilt of the heel. It is the same thing.

How common it is

Very. In the largest study of healthy preschoolers, more than half of all 3-year-olds had a flexible flatfoot. By age 6, about one in four did. Across the whole group of 3- to 6-year-olds, it was a little under half. Boys had flat feet more often than girls, and children who were overweight more often than children who were not.

Those numbers tell the whole story. Flat feet are the usual way a young child's foot is built, and the arch forms gradually over the preschool and early school years. The ligaments tighten, the muscles of the foot and leg get stronger, and the baby fat that fills in the arch melts away. For most children the arch is there by the time they are 6 to 10 years old.

Why there is no window to miss

Parents worry that if they wait, they will have lost the chance to shape the foot while it is soft. I understand the worry, and I can put it to rest: there is no treatment that shapes a growing flexible foot.

This has been tested properly. In a well-known study, young children with flexible flat feet were divided into groups and given corrective shoes, heel cups, custom-molded inserts, or nothing at all, and then followed for three years with X-rays. The arches improved by the same amount in every group, including the children who had no treatment. The foot develops on its own schedule, from the inside, and a shoe or insert on the outside does not change it.

So waiting costs your child nothing. Watching is the treatment.

If the flat foot stays

Some children keep a flexible flatfoot into their teens and adult life. That is still a normal foot. Many adults have flexible flat feet and never think about them. Large studies of young adults, including military recruits examined before training, found that a flexible flatfoot did not cause disability and did not keep people from marching, running, and working. It does not lead to arthritis.

Here is how I check a persistent flatfoot. I look at your child from behind, standing. The Achilles tendon runs down the back of the ankle to the heel. When the heel tilts outward, the tendon angles inward as it comes down. If I then put the heel in a neutral, straight position, the tendon runs straight down. That tells me the heel is flexible and the foot is a normal flexible flatfoot.

Some older children and teenagers find that an arch support or shoe insert feels better, particularly for running and sports, because it holds the heel closer to that straight position while they are on their feet. Others try one and find it uncomfortable or pointless. Both answers are fine. An insert is a comfort item, like a good pair of socks. It is not treatment: take it out, and the foot is exactly as it was. If your child wants to try one, an inexpensive over-the-counter insert is the place to start. If your child does not want one, there is no reason to insist.

Shoes should simply fit well and be comfortable. There are no special shoes to buy.

When to come in

A few foot problems can look like a flatfoot at first glance and do need attention. Please make an appointment if you notice any of these:

• A stiff flatfoot. The arch does not appear when your child stands on tiptoe or sits with the feet dangling, or the heel does not swing inward on tiptoe. In older children and teenagers, the usual cause is a tarsal coalition, where two of the small bones in the back of the foot are joined together by a bridge of bone or cartilage. It typically shows up between about ages 8 and 16, often with aching on the outside of the foot or repeated ankle sprains. A stiff flatfoot in a baby, with a rocker-shaped sole, is a separate and rare condition that also needs an early visit.
• A painful flatfoot. Occasional tired legs after a long day are normal in any child. Pain in the arch, the heel, or the outside of the ankle that comes with activity, limits play, or makes your child want to stop sports is not, and I want to see it.
• A tight heel cord. If your child cannot bring the foot up toward the shin with the knee straight, or walks with the heels barely touching, the calf muscles and Achilles tendon are tight. A tight heel cord pushes the foot flat and can make it ache. Stretching helps, and my calf stretches for children and teens are the place to start.
• A flatfoot on one side only, or one that is clearly getting worse.
• A child with a neuromuscular or genetic condition, such as cerebral palsy, Down syndrome, or a connective tissue disorder, since in those children the foot can keep flattening and sometimes does need support.
• New limping, tripping, or weakness.

Common questions

• Will my child grow out of it? Most do, with the arch appearing between about ages 4 and 10. If it does not, a flexible flatfoot is still a normal foot.
• Should I buy inserts or special shoes now, while the foot is soft? No. They do not change how the foot develops. Comfortable shoes that fit are all a young child needs.
• Will my child be able to play sports? Yes, all of them. Plenty of fast runners and good athletes have flat feet.
• Could this cause knee, hip, or back problems later? There is no good evidence that a flexible flatfoot in a child leads to problems higher up later in life.
• My child's feet roll in when standing. Is that harmful? It can look alarming, but it is exactly what a flexible flatfoot does. If there is no pain, no stiffness, and your child runs and plays normally, nothing needs to be done.
• My own feet are flat. Did my child get this from me? Probably, in part. Flat feet run in families, and that is one more sign that this is a normal variation rather than a disease.
• What if the foot hurts in a few years? Then come back. A painful flatfoot in a teenager is worth a careful look, and most of the time it is treated with stretching, an insert for comfort, and time.

Learn more

OrthoInfo (AAOS), Flexible Flatfoot in Children: orthoinfo.aaos.org (opens in a new tab)

My calf stretches for children and teens, and my guides to in-toeing and toe walking, two other common worries that are usually normal stages of growing.

This information is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. For specific concerns about your child, consult a board-certified, fellowship-trained pediatric orthopaedic surgeon.

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