Flat feet

Flat feet, also called fallen arches, means the arches along the inside of your feet are low or not visible when you stand. One or both feet can be affected.

Many babies and young children have flat-looking feet because their arches are still developing and partly hidden by soft tissue. Some people continue to have flexible flat feet as adults. This is often painless and does not need treatment.

A flexible flat foot has an arch when there is no weight on it, but the arch lowers when you stand. A rigid flat foot stays flat when sitting or standing on tiptoe. Rigid flat feet are less common and more likely to need assessment.

Flat feet can also develop later in life when the tendons and ligaments supporting the arch weaken or are injured. This is sometimes called progressive collapsing foot deformity. It often involves the posterior tibial tendon, which runs behind the inner ankle and helps support the arch.

Flat feet matter mainly when they cause pain, stiffness, difficulty walking or a change in foot shape. Having flat feet without symptoms does not automatically mean something is wrong.

Many people with flat feet have no symptoms. When symptoms occur, they may include:

• Aching in the arch, heel or inner ankle
• Swelling behind or below the inner ankle
• Tired feet after standing or walking
• Stiffness or reduced movement
• Pain on the outside of the ankle
• Uneven shoe wear or uncomfortable shoes
• Difficulty standing on tiptoe on the affected leg

Symptoms may become more noticeable after long periods on your feet, a sudden increase in activity or an injury.

In a child, painless flexible flat feet usually do not limit play or sport. Pain, repeated ankle sprains, unusual shoe wear, stiffness or flatness affecting only one side should be assessed.

In adults, a newly lowering arch, a heel turning outward or the front of the foot pointing outward can suggest that the supporting tendon and ligaments are no longer working normally.

Flat feet do not have one single cause.

In children, flexible flat feet are usually part of normal development. Family foot shape and naturally loose ligaments may contribute. Some people keep a low arch throughout life.

A rigid flat foot may result from bones that developed or joined differently. One example is tarsal coalition, in which bones near the back of the foot are connected. Conditions affecting nerves or muscles can also alter foot shape.

Adult flat feet may develop when the structures supporting an existing arch weaken. Causes include:

• Damage or gradual wear of the posterior tibial tendon
• Previous foot or ankle injury
• Arthritis affecting the foot joints
• Long-term strain on supporting ligaments
• Conditions affecting muscles, nerves or connective tissue

Older age, higher body weight, diabetes and inflammatory arthritis may increase the risk of tendon problems or strain on the feet. Pregnancy can also temporarily lower the arches as body weight and ligament flexibility change.

Flat feet are usually diagnosed through a medical history and physical examination. You may be asked when the shape changed, where it hurts and which activities affect your symptoms.

A healthcare professional may examine your feet while you sit, stand, walk and rise onto your toes. They may check whether the arch returns when weight is removed, whether the heel moves normally and whether the joints are flexible. Strength, sensation and blood flow may also be checked.

Tests are not always needed. Weight-bearing X-rays may be used if there is pain, stiffness, changing foot shape or concern about arthritis or unusual bone development. They are taken while you stand to show how the bones line up under load.

Ultrasound or MRI may be used to examine a tendon, ligament or other soft tissue. Blood tests do not confirm flat feet but may be considered if inflammatory arthritis or another condition is suspected.

Painless, flexible flat feet usually need no treatment. Treatment focuses on relieving symptoms and maintaining movement rather than creating a visible arch.

Supportive, well-fitting shoes may reduce discomfort. A firm heel section and enough room for the toes can help. Shoes should suit the activity and not rub painful areas.

Foot orthoses are inserts worn inside shoes. Ready-made or custom inserts may support the foot and improve comfort, but they do not permanently rebuild an arch. Custom devices are not necessary for everyone.

Exercises may help when the calf or Achilles tendon is tight or foot and ankle muscles need strengthening. A physiotherapist or another qualified professional can recommend exercises that do not increase pain.

For short-term pain, options include reducing aggravating activity, applying ice wrapped in a cloth and using non-prescription pain medicine. Pain medicines are not suitable for everyone. Check the label and ask a pharmacist or healthcare professional if you have other medical conditions, take other medicines or are pregnant.

A painful adult flat foot may need a brace or temporary walking boot. This should be supervised because prolonged immobilisation can weaken muscles and has other risks.

Surgery is uncommon for flexible flat feet without symptoms. It may be considered for persistent pain, worsening deformity or major loss of function despite appropriate non-surgical care. The procedure depends on which tendons, ligaments, joints and bones are affected. Recovery often takes months, and risks include infection, stiffness, nerve irritation and failure of bones to heal fully.

Most painless flexible flat feet do not cause complications.

Painful or progressive flat feet can alter how force passes through the foot and ankle. This may cause ongoing tendon pain, calluses, difficulty fitting shoes or reduced ability to walk and exercise.

Progressive collapsing foot deformity can become increasingly stiff. Arthritis may develop in overloaded joints or existing arthritis may worsen. As the heel turns outward, tissues at the outer ankle may become painfully compressed.

These problems are not inevitable. Early assessment of a newly changing or painful adult foot may help prevent the deformity from becoming rigid.

Developmental or inherited flat feet usually cannot be prevented. Children do not need special shoes, inserts or exercises solely to force a normal-looking arch when their feet are painless and flexible.

Not every adult case can be prevented. Tendons and joints may change because of age, injury, arthritis or other health conditions.

You may reduce avoidable strain by increasing walking or running distances gradually, wearing shoes suited to the activity and allowing injuries time to recover. Managing diabetes or inflammatory arthritis may also support general foot health, although it cannot guarantee that the arches will remain unchanged.

Most children with flexible flat feet remain active and pain-free. Their arches may become more visible as they grow, or their feet may remain flat without causing difficulty. Arch appearance alone does not predict future disability.

Adults who have always had painless flat feet may never need treatment. Comfort, strength and function are more important than whether an arch is visible.

Symptoms following a change in activity may improve over weeks or months with footwear changes, exercises and a temporary reduction in aggravating activity. Inserts may help while worn but generally do not permanently change adult foot structure.

A newly acquired adult flat foot can progress over months or years. Some cases remain manageable without surgery, while others become stiffer or more painful. Follow-up may be useful if the shape continues to change, walking becomes harder or an orthosis or brace needs adjustment.

You can usually remain active, although activity may need to change during painful periods. Cycling or swimming may be more comfortable. Return gradually to usual activity after pain and swelling settle.

Arrange a routine appointment if:

• Foot or ankle pain lasts more than a few weeks
• Pain keeps returning or limits walking, work, sleep or exercise
• One arch is newly lower than the other
• The foot is becoming stiffer or changing shape
• There is swelling or tenderness along the inner ankle
• A child has pain, stiffness, frequent falls or one-sided flatness
• You have diabetes and develop a new foot problem

Seek urgent medical assessment after an injury if you cannot bear weight, the foot looks deformed or pain and swelling are severe.

Get emergency help if the foot becomes suddenly cold, pale or blue, or if there is new major numbness or weakness. These symptoms are not typical of flat feet and may indicate a problem with blood flow or nerves.

A hot, red, rapidly swelling foot with fever also needs urgent assessment, particularly if you have diabetes, reduced immunity or a wound.

Can flat feet be corrected?

Symptoms can often be improved, but inserts and exercises do not permanently create an arch in most adults. Surgery can correct selected painful deformities but is usually reserved for substantial symptoms or progression.

Do flat feet always cause pain?

No. Many children and adults have flat feet without pain or loss of function. Treatment is based on symptoms and stiffness, not appearance alone.

Are flat feet normal in children?

Flat-looking feet are common during early childhood because the arch is still developing. Painless, flexible feet usually do not need treatment. Pain, stiffness or a difference between the feet should be assessed.

Do shoe inserts fix flat feet?

Inserts may support the foot and reduce pain while worn. They usually do not permanently change the bones or restore an adult arch. Ready-made and custom options may help.

Can I run or exercise with flat feet?

Many people with flat feet run and play sport without difficulty. Use comfortable footwear, increase training gradually and respond to persistent pain rather than the appearance of your arches.

Why has one of my feet suddenly gone flat?

A new change in one adult foot can follow an injury or weakening of the tendon and ligaments supporting the arch. Arrange an assessment, especially if there is inner ankle pain, swelling or difficulty standing on tiptoe.