Flat feet (pes planus) is a condition in which the foot does not have a normal arch when standing.
Pes planovalgus; Fallen arches; Pronation of feet; Pes planus
Causes, incidence, and risk factors
Flat feet are a common condition. In infants and toddlers, they are normal.
Flat feet occur because the tissues holding the joints in the foot together (called tendons) are loose. In infants and babies, the fat in the foot is also a factor.
As children grow older, these tissues tighten and form an arch, most often by the time the child is 2 or 3 years old. By adulthood, most people have normal arches. However, in some people this arch may never form.
Aging, injuries, or illness may harm the tendons and cause flat feet to develop in a person who has already formed arches. This type of flat foot may only be on one side.
Rarely, painful flat feet in children may be caused by a condition in which two or more of the bones in the foot grow or fuse together. This condition is called tarsal coalition.
Most flat feet do not cause pain or other problems.
At times, foot pain, ankle pain, or lower leg pain are present (especially in children). They should be evaluated by a health care provider.
Adults may notice some symptoms. Their feet may become achy or tired when standing for long periods of time or after playing sports.
Signs and tests
In people with flat feet, the instep of the foot comes in contact with the ground when they stand.
The health care provider will ask you to stand on your toes. If an arch forms while you are standing on your toes, the flat foot is called flexible. No treatment or further work-up is needed.
If the arch does not form with toe-standing (caled rigid flat feet), or if there is pain, other tests may be needed, including:
Once your health care provider has examined your child, no treatment is needed for flat feet that are not causing any pain or problems walking.
Your child's feet will grow and develop the same, whether special shoes, shoe inserts, heel cups, or wedges are used.
Your child may walk barefoot, run or jump, or do any other activity without making the flat feet worse.
In older children and adults, flexible flat feet that are painless and do not cause problems with walking do not need further treatment once a health care provider has evaluated them.
If you have pain due to flexible flat feet, the following may help:
An off-the-shelf or custom-made orthotic (arch-supporting insert in the shoe)
Rigid or painful flat feet require evaluation by a health care provider. The treatment depends on the cause of the flat feet.
For tarsal coalition, treatment starts with rest and possibly a cast. If this does not improve the pain, surgery may be needed.
In more severe cases, surgery may be needed to:
Clean or repair the tendon
Fuse some of the joints of the foot into a corrected position
Flat feet in older adults can be treated with pain relievers, orthotics, and sometimes surgery.
Most cases of flat feet are painless and do not cause any problems or need treatment.
Some causes of painful flat feet can be successfully treated without surgery, but surgery is the last option to relieve pain in some cases.
Patients who need to have surgery often report improvement in pain and function.
Flat feet rarely cause any complications except pain.
Possible problems after surgery include:
Failure of the fused bones to heal
Foot deformity that does not go away
Loss of ankle movement
Pain that does not go away
Calling your health care provider
Call your health care provider if you experience persistent pain in your feet or your child complains of foot pain or lower leg pain.
Most cases are not preventable.
Hosalkar HS, Spiegel DA, Davidson RS. The foot and toes. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap. 673.
Wexler D, Kile TZ, Grosser DM. Posterior tibial tendon dysfunction. In: Frontera WR, Silver JK, eds. Essentials of Physical Medicine and Rehabilitation. 2nd ed. Philadelphia, Pa: Saunders Elsevier; 2008:chap. 87.
C. Benjamin Ma, MD, Associate Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.