Dr. Danial Sharifi RazaviFoot and ankle surgeon, with a special focus on children and adolescents

Flatfoot (Pes Planovalgus)

Also known as: Fallen arches, Pes planus, Pes planovalgus, صافی کف پا

A flat arch is normal in most young children and painless in most adults. The question that matters is not whether the arch is low, but whether the foot is stiff, painful, or getting worse.

Book an appointment

What it is

The arch of the foot is held up by the shape of the bones, the ligaments that tie them together, and the tendons that run under and behind them. When the arch sits low, the heel tips outward and the front of the foot turns out. That combination is what "flatfoot" describes.

A low arch is not in itself a disease. It is a normal variant in a large part of the population, and most people who have one will never have a problem. What matters clinically is whether the foot is flexible or rigid, whether it hurts, and whether it is changing over time.

In children

Every small child looks flat-footed. The arch is filled with a fat pad, the ligaments are lax, and the bones have not finished forming. The arch appears on its own in most children between the ages of about four and ten.

A flexible, painless flatfoot in a child needs reassurance, not treatment. Insoles have been studied repeatedly and do not change the shape the foot ends up with.

Assessment is warranted when the flatfoot is:

  • painful, particularly under the inner ankle or in the outer part of the hindfoot
  • rigid, with no arch appearing on tiptoe
  • one-sided, or clearly worse on one side
  • associated with a tight calf, which drives the deformity and can often be treated on its own
  • accompanied by clumsiness or worsening walking, which raises the question of an underlying neurological cause

In adults

An adult arch that was once normal and is now collapsing is a different problem. The usual cause is progressive failure of the posterior tibial tendon, the tendon that runs behind the inner ankle and lifts the arch with every step. It presents as pain and swelling on the inside of the ankle, an arch that is flattening, and increasing difficulty rising onto tiptoe on that leg.

This condition is progressive. Treated early, while the foot is still flexible, the options are simple and the results are good. Left for years, the hindfoot stiffens and the choices narrow to fusion. Early assessment genuinely changes the outcome.

How it is assessed

  • Examination standing and walking, which is the part that matters most. A flatfoot cannot be assessed on a couch.
  • The tiptoe test, to separate flexible from rigid.
  • Calf tightness (Silfverskiold test), because a tight gastrocnemius is a common and correctable driver.
  • Weight-bearing radiographs. Films taken lying down are of little use. Standing films let the alignment be measured, typically the Meary angle, calcaneal pitch, talonavicular coverage and Kite angle.
  • MRI or CT only where a tendon tear, a coalition or arthritis is suspected.

Treatment without surgery

This is where most people start, and where most people stay.

  • Calf stretching, done properly and for long enough. A tight calf forces the arch down at every step.
  • Strengthening of the posterior tibial and intrinsic foot muscles.
  • Supportive footwear, and an orthosis where it helps comfort.
  • Activity and load management, and weight reduction where relevant.
  • A period of immobilisation in a boot for an acutely inflamed tendon.

When surgery is considered

Surgery is for a foot that stays painful after a genuine trial of non-operative treatment, or a deformity that is clearly progressing. The operation is planned around what is actually wrong, and usually combines two or three of the following:

  • Calf lengthening (gastrocnemius recession) where the calf is tight.
  • Calcaneal osteotomy, cutting and shifting the heel bone back under the leg to restore alignment.
  • Lateral column lengthening, to correct the outward rotation of the forefoot.
  • Arthroereisis or a calcaneo-stop screw in the growing child: a small implant in the sinus tarsi that limits the collapse while the foot grows. It is minimally invasive and reversible, and the implant is usually removed later. After it, walking usually starts on the day of surgery, as comfort allows.
  • Tendon transfer or repair, where the posterior tibial tendon has failed.
  • Fusion, restricted to feet that are already rigid or arthritic.

The principle throughout is to correct the alignment while keeping the joints moving. Fusing a flexible foot solves the shape and creates a new problem.

Typical recovery after surgery

A typical course. Your own plan is set at your visit and depends on the operation.

  1. Surgery to week 6Below-knee cast or splint for about a month, foot elevated most of the time. Walking with crutches or a walker, no weight on the operated foot until about day 40. Stitches usually come out at about two weeks. Taking the cast off does not mean walking is allowed.
  2. Weeks 6 to 10Once the surgeon confirms the bone has healed, a walking boot and gradually more weight on the foot, with crutches or a walker; the team says how much. Physiotherapy starts for ankle movement and calf strength.
  3. Months 2 to 3Ordinary shoes and walking without crutches. Balance work on one leg may wait until the third month or later. Swelling after standing for long is still normal.
  4. Months 3 to 6A gradual return to running and sport, as the surgeon advises. Full recovery after surgery usually takes three to six months.
  5. Up to a yearSwelling settles. The final shape of the foot is judged at about one year.

Common questions

My child has flat feet. Does it need treating?

Usually not. Almost every toddler has a flat arch, and the arch develops on its own in most children by the age of eight to ten. If the foot is flexible, painless, and the child runs and plays normally, no treatment is needed and insoles do not change the final shape of the foot. Treatment is considered when the foot hurts, when it is stiff rather than flexible, or when one foot is clearly different from the other.

Do insoles cure flat feet?

No. Insoles can relieve pain and reduce fatigue by supporting the foot, and they are worth trying. They do not build an arch and they do not change the underlying shape of the bones. Their job is comfort, not correction.

How do I know if my flatfoot is flexible or rigid?

A simple test: stand on tiptoe. If an arch appears and the heel swings inward, the flatfoot is flexible. If the foot stays flat and the movement is painful, it may be rigid, which points to a different cause such as a tarsal coalition and needs imaging.

Will surgery leave my child with a stiff foot?

The whole aim of modern flatfoot surgery in children is to correct the alignment without fusing joints, precisely so that movement is preserved. Fusion is reserved for feet that are already stiff and arthritic, which is rare in children.

Can both feet be operated on at the same time?

Usually one foot is done at a time, with the second a few months later. But in young people under 14 who weigh less than 50 kg, both feet can usually be operated on together with the minimally invasive technique.

This page is for patient information and does not replace an examination by a doctor.