Flexible Flatfoot

What it is

Flexible flatfoot (pes planus) is when a child's arch looks flat while standing but reappears when sitting or on tiptoe. It is "flexible" because the foot still moves normally. It is very common in children and is usually a normal part of development.

Why it happens

Most children are born with flat feet, and the arch gradually develops — usually by age 6–10. Contributing factors include the normal ligament looseness of growing children, delayed arch development, family history, and extra weight (which loads the arch). Rarely, an underlying cause is present, such as a tarsal coalition, a neuromuscular condition (e.g., cerebral palsy, Charcot-Marie-Tooth), or a genetic syndrome (e.g., Down syndrome).

Signs and symptoms

Most children have no symptoms. When present, they may include:

• Tired or aching feet, especially after long periods of walking.
• Arch or heel pain (inner foot, Achilles, or sinus tarsi region).
• A flattened arch with the ankle rolling inward (pronation).
• Uneven shoe wear.
• Reduced stamina during sports.

How it is diagnosed

Diagnosis is clinical: looking at the arch while standing, sitting, and on tiptoe; checking for heel valgus (outward tilt of the heel) on standing and for the arch returning on tiptoe; and a Silfverskiöld test for Achilles tightness. X-rays or MRI are used only if pain is persistent, the deformity is rigid or one-sided, or an underlying problem is suspected.

Treatment

For a flexible flatfoot with no symptoms, no treatment is needed — reassurance and observation are key, and the arch usually improves with growth.

For a symptomatic flexible flatfoot, options include supportive footwear (a firm heel counter and arch support), over-the-counter orthotics for comfort (not to "correct" the arch), physical therapy (Achilles and hamstring stretching, foot strengthening), activity modification when symptoms flare, and weight management when relevant.

Surgery is rarely needed and is considered only for persistent, limiting symptoms, a deformity that becomes rigid, or failure of non-operative care. Options can include Achilles lengthening, a calcaneal osteotomy, subtalar arthroereisis in selected cases, medial column procedures, or — only in severe or pathologic cases — a fusion.

Recovery and long-term outlook

The outlook is excellent: most children without symptoms develop a normal arch by adolescence, and symptomatic children usually improve with conservative care. Surgery is rarely needed, and flexible flatfoot is not associated with future arthritis or disability.

When to call the office

• Foot pain that limits daily activity.
• Loss of flexibility or a stiff / rigid arch.
• A one-sided (unilateral) flatfoot.
• New neurologic symptoms or an abnormal gait.
• Frequent tripping or fatigue with walking.
• Uneven shoe wear or a developing bunion.

Common questions

• Will my child grow out of flatfoot? Most children develop a visible arch by adolescence as the ligaments tighten and muscles strengthen.
• Do orthotics help? They may improve comfort in symptomatic cases, but they do not change the shape of the foot or prevent future problems in children without symptoms.
• Will this lead to problems as an adult? Not in most cases — flexible flatfoot in children almost never causes long-term disability.
• Is surgery ever needed? Very rarely, and only for persistent, painful, or rigid deformities that do not respond to conservative care.
• Should I worry about the ankle rolling in? It can look concerning, but it is often a normal part of development. If your child has no pain or trouble walking, there is usually no cause for concern.
• Can we get ahead of the problem now? The best approach is observation and reassurance — unnecessary treatments have not been shown to help and may add cost or stress without benefit.
• What if my child has a condition like Down syndrome or cerebral palsy? Children with neuromuscular or syndromic conditions are at higher risk for progression and may benefit from earlier orthotic support and close monitoring.

This information is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. For specific concerns about your child, consult a board-certified, fellowship-trained pediatric orthopaedic surgeon.