Flat Feet Explained: Why Arches Collapse and How to Treat the Pain

Most people don’t give much thought to their arches—until they start to hurt. Flat feet (also known as fallen arches or pes planus) are extremely common in adults. For some, it’s simply the way their feet are shaped and doesn’t cause any issues. For others, flat feet can lead to pain, fatigue, imbalance, or even long-term foot and ankle problems.

So how do you know when flat feet are normal—and when they’re a problem that needs treatment?

At Restore Foot & Ankle Specialists, we help patients every day determine what’s causing their symptoms and how to keep their feet supported, stable, and pain-free. Here’s everything you need to know.

What Are Flat Feet?

Flat feet occur when the arches of the feet are lower than normal—or appear not to exist at all. In many adults, flat feet develop slowly over time as tendons weaken, ligaments stretch, and the arch loses its natural shape.

There are two main types:

1. Flexible Flat Feet

• Arches appear when sitting or on tiptoes

• Flatten when standing

• Often hereditary

• Frequently painless

2. Rigid Flat Feet

• Arches remain flat in all positions

• Often associated with underlying structural issues

• More likely to cause discomfort, stiffness, and limited mobility

When Flat Feet Are Normal

Flat feet can be completely normal if:

• You’ve had them your whole life

• They don’t cause pain in the feet, ankles, knees, or back

• You can walk and exercise without discomfort

• Your foot remains flexible and mobile

• You have no swelling or deformity

Many people with flexible flat feet live active, pain-free lives without needing treatment.

When Flat Feet Become a Problem

Flat feet can lead to symptoms when the arch collapses to the point that it affects alignment, stability, and tendon function.

Signs that flat feet are becoming a problem include:

1. Arch or Heel Pain

Pain in the arch can indicate stress on the plantar fascia, while heel pain may suggest plantar fasciitis.

2. Swelling or Tenderness Along the Inside of the Ankle

This can indicate Posterior Tibial Tendon Dysfunction (PTTD)—one of the most common causes of progressive flat feet in adults.

3. Aching After Standing or Walking

Flattened arches can lead to fatigue as the foot struggles to maintain support.

4. Overpronation

When the foot rolls inward excessively, it can cause:

• Shin splints

• Knee pain

• Hip discomfort

• Lower back pain

5. Difficulty or Pain Rising onto Your Toes

This is a key sign of a weakening posterior tibial tendon.

6. Changes in the Shape of the Foot

Some adults notice:

• A more prominent “bump” on the inside of the ankle

• Feet that appear to turn outward

• Shoes wearing out unevenly

If you’re experiencing any of these symptoms, it’s time to get evaluated.

What Causes Flat Feet in Adults?

Common causes include:

• Genetics (inherited foot structure)

• Posterior tibial tendon dysfunction (most common acquired cause)

• Injury, such as an ankle sprain or fracture

• Arthritis, especially in older adults

• Obesity, which increases pressure on the arch

• Diabetes, which affects tendon strength

• Tight Achilles tendon, altering foot mechanics

• Pregnancy, which increases laxity in ligaments

How Flat Feet Are Diagnosed

During your visit, a podiatrist will:

✔ Examine your walking pattern (gait)
✔ Evaluate arch height and foot flexibility
✔ Assess for swelling, tenderness, or deformity
✔ Perform imaging if needed (X-ray, MRI, or ultrasound)

This helps determine the underlying cause and guides treatment.

Treatment Options for Painful Flat Feet

The good news: most cases can be treated without surgery.

1. Custom Orthotics

Orthotics support the arch, correct overpronation, and improve alignment. They are one of the most effective treatments for symptomatic flat feet.

2. Supportive Footwear

Shoes should offer:

• Firm heel counter

• Good arch support

• Shock absorption

• Motion control features

Avoid unsupportive flat shoes, flip-flops, or worn-out sneakers.

3. Physical Therapy

Strengthening and stretching exercises help stabilize the arch, especially if PTTD is involved.

4. Anti-Inflammatory Measures

• Ice

• NSAIDs

• Topical pain relievers

These reduce symptoms during flare-ups.

5. Bracing

An ankle brace or supportive boot may be used to reduce strain on the posterior tibial tendon.

6. Weight Management

Reducing excess weight lowers pressure on the arches.

When Surgery Is Necessary

Surgery is considered when:

• Severe pain persists despite treatment

• Significant deformity is present

• The posterior tibial tendon is torn or severely damaged

• Arthritis or joint collapse develops

Surgical options may include tendon repair, osteotomies (bone realignment), or joint fusion, depending on the severity.

Can Flat Feet Be Prevented?

While you can’t change your foot structure, you can prevent progression by:

• Wearing supportive shoes

• Using custom orthotics

• Stretching tight calf muscles

• Strengthening foot and ankle muscles

• Addressing injuries early

The Bottom Line

Flat feet in adults are common—and not always a problem. But when they cause pain, swelling, or changes in how you walk, they may require attention from a foot and ankle specialist.

At Restore Foot & Ankle Specialists, we evaluate your foot structure, biomechanics, and symptoms to create a personalized treatment plan that restores comfort and function.

If your arches are collapsing or foot pain is interfering with your life, schedule an appointment today—your feet will thank you. Contact our office today with Dr. Gireesh Reddy or Dr. Sirisha Pokala by calling (469) 573-3427 or by booking an appointment online.