Flat feet

Flexible and rigid flat feet

A flexible flat foot has an arch that appears when you sit or rise onto your toes and flattens when you stand. It is common, often runs in families, and usually causes no trouble. A rigid flat foot stays flat all the time and is more likely to have an underlying cause worth finding, such as arthritis or a joint coalition.

When the arch collapses in adulthood

The posterior tibial tendon runs behind the inside ankle bone and supports the arch. When it becomes inflamed, stretched or torn, the arch gradually collapses, the heel tilts outward and the forefoot points out. Early on, the main symptoms are pain and swelling along the inside of the ankle; later the pain can move to the outside of the ankle, and standing on tiptoe on that foot becomes difficult.^[1,5] Prompt treatment matters, because early diagnosis is one of the most important factors in the outcome.^[2]

How we evaluate it

We look at your feet standing and walking, check the arch, heel position, calf tightness and the strength of the tendon (including a single-leg heel rise), and compare both sides. Standing X-rays at the practice show the alignment of the bones; ultrasound or MRI can show the condition of the tendon.^[6]

Treatment at the practice

• Supportive shoes, orthotics or a brace to support the arch and take stress off the tendon.^[2,6] Evidence for orthoses in adult flatfoot is limited, so we use them as part of a plan rather than on their own.^[7] See custom orthotics.
• A structured exercise program. In one program for early-stage tendon dysfunction, an orthosis with high-repetition strengthening exercises over about four months gave a successful result in most patients.^[3]
• Calf stretching when a tight calf is adding to the strain.
• A short period in a boot for an acutely inflamed tendon.

For painful flat feet in children, we check whether the foot is flexible, look for tight calves and other causes, and use supportive shoes and exercise first. Orthoses have a limited evidence base in children without symptoms.^[4] See children’s foot care.

Common questions

My feet are flat but don’t hurt. Do I need orthotics?

Usually not. Flat feet that don’t hurt, tire easily or change shape generally need no treatment. Adults with painful flat feet can benefit from inserts as part of a plan, though the evidence for orthoses on their own is limited.^[7]

Can exercises rebuild my arch?

Exercises don’t change the shape of the bones, but strengthening the posterior tibial tendon and the muscles of the foot can relieve pain and help the tendon cope. In one program, most people with early tendon dysfunction did well with an orthosis and high-repetition strengthening over about four months.^[3]

Why do you ask me to stand on tiptoe on one foot?

The single-leg heel rise tests the posterior tibial tendon. Difficulty rising onto the toes of one foot, or a heel that doesn’t swing inward as you rise, is a sign the tendon is struggling.^[1,5]

What happens if I ignore a flattening arch?

A collapsing arch can keep progressing, and a flexible deformity can become rigid, which narrows the options. Early diagnosis is one of the most important factors in how well treatment works.^[2]

When surgery is considered

Surgery is considered if pain does not improve after several months of appropriate treatment, or if the deformity is progressing.^[1,2]

When to seek care