Flat Feet (Pes Planus)

ICD-10: M21.4 Affects 20-30% of the population

What are Flat Feet?

Flat feet, also known as pes planus or fallen arches, is a condition where the arch of the foot collapses, causing the entire sole of the foot to come into complete or near-complete contact with the ground. While some people are born with flat feet, others develop the condition over time due to various factors.

In a normal foot, the arch is formed by the tarsal and metatarsal bones and supported by ligaments and tendons, particularly the posterior tibial tendon. When these structures weaken or become damaged, the arch can collapse, leading to flat feet. This condition can affect one or both feet and may be flexible (the arch appears when not weight-bearing) or rigid (no arch is visible even when not standing).

Symptoms of Flat Feet

Many people with flat feet experience no symptoms at all. However, when symptoms do occur, they can range from mild discomfort to significant pain and functional limitations.

Associated Symptoms

  • Arch or heel pain
  • Calf muscle fatigue
  • Difficulty standing on tiptoes
  • Inward rolling of the ankle
  • Back and hip pain
  • Shoe wear abnormalities

Types of Flat Feet

Flexible Flat Feet

The most common type. The arch is visible when sitting or on tiptoes but disappears when standing. Usually causes few symptoms in childhood but may cause problems later in life.

  • Arch visible when not weight-bearing
  • Often painless in children
  • May develop symptoms with age
  • Usually bilateral (both feet)

Rigid Flat Feet

No arch is visible whether standing or sitting. Often more symptomatic and may require more aggressive treatment.

  • No arch visible in any position
  • More likely to cause pain
  • May limit ankle motion
  • Often requires treatment

Adult Acquired Flat Feet

Develops in adulthood, often due to posterior tibial tendon dysfunction. Can be progressive and may require surgical intervention.

  • Develops after normal arch formation
  • Often unilateral (one foot)
  • Progressive arch collapse
  • Frequently symptomatic

Symptom Progression

Early Stage

Minimal symptoms, occasional foot fatigue after prolonged standing or walking. Arch may be slightly lower than normal.

Moderate Stage

Increased pain in the arch, ankle, or heel. Swelling along the inside of the ankle. Difficulty with activities requiring quick movements.

Advanced Stage

Severe pain and deformity. Arthritis may develop in the foot and ankle. Significant functional limitations in walking and standing.

Causes and Risk Factors

Congenital Causes

  • Genetic Factors: Family history of flat feet
  • Tarsal Coalition: Abnormal connections between foot bones
  • Congenital Vertical Talus: Rare birth defect affecting foot development
  • Developmental Abnormalities: Problems with normal arch development

Acquired Causes

  • Posterior Tibial Tendon Dysfunction: Most common cause in adults
  • Injury or Trauma: Fractures, sprains, or torn tendons
  • Arthritis: Rheumatoid arthritis or osteoarthritis
  • Neurological Conditions: Cerebral palsy, muscular dystrophy
  • Age-related Changes: Weakening of tendons and ligaments over time

Risk Factors

Modifiable Risk Factors

  • Obesity or excessive weight
  • Poor footwear choices
  • Sedentary lifestyle
  • Occupations requiring prolonged standing

Non-Modifiable Risk Factors

  • Age (risk increases with age)
  • Gender (more common in women)
  • Genetics and family history
  • Certain ethnic backgrounds

Diagnosis

Diagnosing flat feet involves a comprehensive evaluation of foot structure, function, and symptoms:

Physical Examination

  • Visual Inspection: Assessment of foot shape and arch height
  • Footprint Analysis: Examination of wet footprint patterns
  • Single-Heel Rise Test: Ability to rise on one foot's tiptoes
  • Range of Motion Testing: Flexibility of foot and ankle joints
  • Strength Testing: Assessment of muscle strength

Imaging Studies

  • X-rays: Weight-bearing X-rays to assess bone alignment
  • CT Scan: Detailed bone structure evaluation
  • MRI: Assessment of soft tissues, tendons, and ligaments
  • Ultrasound: Evaluation of tendon integrity

Specialized Tests

  • Foot Pressure Analysis: Distribution of pressure across the foot
  • Gait Analysis: Assessment of walking patterns
  • 3D Foot Scanning: Detailed foot shape analysis
  • Flexibility Testing: Distinguishing flexible from rigid flat feet

Treatment Options

Treatment for flat feet depends on the severity of symptoms, type of flat feet, and impact on daily activities. Many cases can be managed conservatively.

Conservative Treatment

Orthotic Devices

Custom or over-the-counter arch supports, shoe inserts, and orthotics to provide arch support and improve foot alignment.

Proper Footwear

Supportive shoes with good arch support, motion control, and adequate cushioning. Avoid high heels and unsupportive footwear.

Physical Therapy

Exercises to strengthen foot and ankle muscles, improve flexibility, and correct gait abnormalities.

Activity Modification

Limiting high-impact activities and incorporating low-impact exercises like swimming or cycling.

Weight Management

Maintaining a healthy weight to reduce stress on the feet and supporting structures.

Medical Treatment

Medications

Anti-inflammatory drugs (NSAIDs) to reduce pain and inflammation. Topical analgesics for localized pain relief.

Injections

Corticosteroid injections for severe inflammation and pain that doesn't respond to other treatments.

Bracing

Ankle-foot orthoses (AFO) or other bracing devices for severe cases requiring additional support.

Surgical Treatment

Tendon Repair

Repair or reconstruction of the posterior tibial tendon in cases of tendon dysfunction.

Osteotomy

Cutting and repositioning bones to improve foot alignment and create an arch.

Arthrodesis

Fusion of joints in severe cases with arthritis and rigid deformity.

Tendon Transfer

Moving healthy tendons to replace damaged ones and restore foot function.

Prevention

While genetic flat feet cannot be prevented, certain measures may help prevent acquired flat feet or reduce symptoms:

Footwear and Support

  • Wear supportive shoes with good arch support
  • Use arch support insoles when needed
  • Avoid walking barefoot on hard surfaces
  • Replace worn-out shoes regularly

Exercise and Strengthening

  • Perform foot and ankle strengthening exercises
  • Include calf stretches in your routine
  • Practice balance and proprioception exercises
  • Maintain overall physical fitness

Lifestyle Factors

  • Maintain a healthy body weight
  • Avoid prolonged standing on hard surfaces
  • Take breaks during long periods of standing or walking
  • Seek early treatment for foot injuries

Helpful Exercises

Toe Raises

Stand with feet flat, lift toes while keeping heels down. Hold for 5 seconds, repeat 10 times.

Calf Raises

Rise up on toes, hold for 5 seconds, lower slowly. Repeat 15-20 times.

Arch Rolls

Roll a tennis ball under the foot arch for 1-2 minutes per foot.

Towel Curls

Use toes to scrunch a towel toward you while seated. Repeat 10 times per foot.

Prognosis and Outlook

The prognosis for flat feet varies depending on the type, severity, and underlying cause:

Flexible Flat Feet

Most people with flexible flat feet lead normal, active lives with minimal or no symptoms. Conservative treatment is usually very effective.

Rigid Flat Feet

May require more intensive treatment and have a more guarded prognosis. Early intervention can prevent progression and improve outcomes.

Adult Acquired Flat Feet

Prognosis depends on early recognition and treatment. Advanced cases may require surgery but generally have good outcomes with appropriate intervention.

When to Seek Medical Attention

Seek Immediate Care If:

  • Severe foot pain following an injury
  • Inability to bear weight on the foot
  • Signs of infection (fever, warmth, redness)
  • Sudden onset of severe foot deformity

Schedule an Appointment If:

  • Persistent foot, ankle, or leg pain
  • Difficulty with walking or standing
  • Visible changes in foot shape
  • Problems finding comfortable shoes
  • Recurring injuries or falls

Medical Disclaimer

This information is for educational purposes only and should not replace professional medical advice. Always consult with a qualified healthcare provider for proper diagnosis and treatment of flat feet or any other medical condition.