Flatfoot (Pes Planus)

  • Medical Author:
    Philip A. Radovic, DPM, FACFAS

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

What is flatfoot?

When the entire sole of the foot is in contact or near contact with the ground while standing, it is considered a flat foot. The result is that there is no arch to the foot. Flatfoot is a common disorder. It is a complex deformity, and there are types and stages that vary in degree of symptoms and disability. Flatfeet are also referred to as pes planus, posterior tibial tendon dysfunction, and fallen arches.

What are the different types of flatfoot?

There are two general types of flatfoot; flexible flatfoot and rigid flatfoot. If a person is sitting or standing on their toes and they have an arch that disappears when they stand with the entire foot on the ground they have a flexible flatfoot. If there is no arch, whether sitting or standing, they have a "rigid" or "true" flatfoot.

Flexible flatfoot is sometimes called "pediatric flatfoot" because it is first apparent in childhood. Congenital or rigid "true flatfoot" (talipes planovalgus) is much less common in children. Of note, almost all infants appear to have a flatfoot due to the fat pad on the sole of their feet and that the arch does not develop until 5 or 6 years of age.

When a rigid flatfoot develops in adults, it is called "adult acquired flatfoot" or "posterior tibial tendon dysfunction." This type of flatfoot develops because of the weakening of the tibialis posterior muscle tendon, which is a major supporting structure of the foot arch. It is a condition that leads to flattening of the arch and rolling in of the ankle. It is a progressive deformity with early symptoms of pain and swelling at the inside arch of the foot that progresses to the outside of the foot below the ankle. It eventually may lead to arthritis of the foot and ankle joints.

Flexible flatfoot is usually in both feet where posterior tibial tendon dysfunction or adult acquired flatfoot can occur in one or both feet.

Quick GuideCommon Causes of Foot Pain

Common Causes of Foot Pain

What are other causes of flatfoot?

As described above, a person may be born with a flatfoot, pediatric flexible flatfoot, or develop it as an adult (adult acquired flatfoot). Less common causes of flatfoot include the following:

  • Tarsal coalitions: A condition where joints bridge or grow together restricting or prohibiting movement of that joint.
  • Accessory navicular bone (os tibiale externum): a small extra bone in the posterior tibial tendon that causes a weakening of support to the arch
  • Ligament laxity in diseases such as Marfan syndrome or Ehlers-Danlos syndrome
  • Charcot arthropathy
  • Trauma
  • Obesity
  • Diabetes
  • Neuropathy
  • Age
  • Pregnancy, due to hormonal changes such as increases in elastin
  • Osteoporosis
  • Overuse

What are flatfoot symptoms and signs?

A flatfoot may cause no symptoms. Symptoms of flatfoot include pain that may be in the inside arch, heel, or ankle and on the outside of the foot just below the ankle. Flattening of the arch can lead to rolling in of the foot and ankle and tilting outward of the heel. Flatfoot can also cause shin pain (shin splints), and aching of the knee, hip, and/or lower back.

How is flatfoot diagnosed?

One may look at their feet to see if they have an arch when standing barefoot for a general assessment. A foot specialist will provide an in-depth evaluation usually including X-rays to determine the precise type of flatfoot, its cause, and potential treatments.

What is the treatment for flatfoot?

It really depends on the type of flatfoot, its stage of progression, and the symptoms. Early treatment is advised whether one's condition is a flexible, rigid, or adult acquired flatfoot. Treatments include proper shoe gear, over-the-counter inserts, custom functional orthotics, bracing, casting, physical therapy, NSAIDs, weight loss, changes in activities, and surgery.

What is the prognosis of flatfoot?

This really depends on the type and severity of the flatfoot. Many people with pediatric or flexible flatfoot function without any signs or symptoms and are unrestricted in their levels of activity. These people do perfectly well without any treatments. Adult acquired flatfoot or true rigid flatfoot tends to be progressive, leading to functional disability and progression of symptoms that interfere with normal daily activities.

Medically reviewed by Aimee V. HachigianGould, MD; American Board of Orthopaedic Surgery


American College of Foot and Ankle Surgeons

American Podiatric Medical Association

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