July 18, 2024

Flat foot deformity is due to depression or complete loss of the longitudinal arch of the foot which can be due to congenital or acquired cause.

Anatomy of the arch of the foot

Two Arch are present

1. Longitudinal Arch

  • Medial and lateral

2. Transverse Arch

  • Anterior and posterior

Functions of arch

  • Body weight distribution
  • Acts as a spring which helps in walking and running
  • Acts as a shock absorber in stepping and particularly in jumping
  • Concavity of arches protects the soft tissue of the sole against pressure
Arch of foot
Medial Longitudinal archLateral Longitudinal arch
SummitThe anterior surface of the talusArticular facet on superior surface of calcaneum
Anterior EndHead of 1-3 metatarsalHead of 4,5 metatarsal
Anterior pillarTalus, navicular, and cuneiform4-5 metatarsals
Posterior EndMedial tubercle of calcaneumLateral tubercle of calcaneum
Posterior pillarCalcaneumLateral Half of calcaneum

Anterior transverse arch:


Formed by the head of 5 metatarsals

Posterior transverse arch:


Only the lateral end touches the ground

Made by 3 cuneiforms and cuboid

Different types of foot arch and deformity
Different types of foot arch and deformity

Flat foot: Pes Planus

Depression or complete loss of the longitudinal arch of the foot

  • Forefoot: Abducted
  • Navicular/ Head of talus: Prominent on the medial side
  • Calcaneum: Valgus
  • Calcaneum: displaced medially and posterior end displaced laterally
  • Talus: Displaced medially and downward
  • Navicular, cuneiform, and cuboid: Wedge shape due to secondary effects and apex directed laterally and dorsally



  • Plantar
  • Calcano-navicular
  • Deltoid


  • Dorsal
  • Lateral

Anterior and posterior tibial tendon and plantar muscle stretched

Achilles tendon: Shortened


1. Congenital

a. Hypermobile

  • Hereditary
  • Marked laxity of ligaments
  • Mid-tarsal/ Sub talar – hypermobile
  • Tendoachillis shortening: Limits dorsiflexion of the ankle
  • Deformity disappears when feet are non-weight-bearing

JACK TEST: POSITIVE (Dorsiflexion of big toe creates an arch in the foot)

b. Rigid with tarsal abnormalities

  • Due to the bridge of bone, cartilage, and fibrous tissue between calcaneum and talus
  • Navicular- calcaneum ( tarsal coalition)

2. Acquired

Clinical Features of Congenital flat foot

Pain and fatigue start on walking or standing

1. Flat foot on only weight-bearing

2. Contraction of tendoachillis: Limitation of dorsiflexion of the ankle

3. hypermobility of subtalar-midtarsal joint ( due to ligamentous laxity)


Burning sensations

Easily fatigued

Clumpy Gait

Pain Increases on standing then walking/ running


Radiological Investigation

Medial displacement of the talus

Anterior projection of the head of the talus

Divergence of the long axis of talus from the calcaneum

Talus is not superimposed with the calcaneum

Flattening of the longitudinal arch in lateral view

Talus and 1st metatarsal angle is 0 degree

In flexible flatfoot apex is plantarward

Meary's angle
Meary’s angle

Treatment Options:

Surgical procedures are limited to 10-15 years unless the child is severely disabled (Grice Procedure)


To release ligamentous tension

Transfer weight (body) to the outer side of the foot

Strengthens invertor and plantar flexors

1. Arch support individual: Application may reduce symptoms but doesn’t influence foot growth. So, not prescribed is asymptomatic patients

2. Shoes

3. Exercises (Improve the strength of muscles: Muscle power)


Most preferably

1. Joint Sparing procedure + Soft tissue imbrications

As Tarsal fusion procedure ( induce OA in adjacent joints)

Sub talar fusion (Altered mechanics of hindfoot and entire midfoot)

Tendoachillis (Contracted): Percutaneous lengthening

Lateral Column Lengthening + Imbrication of talonavicular cuneiform complex

( Osteotomy of calcaneum neck between an anterior and middle facet.

Sliding Calcaneal Osteotomy:


Acquired Flat foot

Etiology of acquired flat foot

  • Tibialis posterior tendon dysfunction
  • OA and inflammatory arthritis and midtarsal joint
  • Trauma
  • Neuropathic (Charcot) foot
  • Infection

Tibialis Posterior tendon Dysfunction

The essential dynamic stabilizer of the medial longitudinal arch of the foot

Repetitive microtrauma with poor blood supply (cause of tendinosis)

Middle-aged women with HTN and DM facilitate the process of degeneration

Classification: Johnson’s and Strom’s

Stage ITendon is inflamed but intact
Stage IITendon become dysfunctional and arch collapse (passively correctable)
Stage IIISubtalar arthritis develops (fixed deformity)
Stage IV (Myerson)Ankle shows arthritis changes

Clinical Features

Pain- medial aspect of the foot

Tenderness/ Swelling – medial malleolus difficulty in inverting the foot

Valgus deformity


Conservative treatment:

Below Knee cast for Month (1-2 months) + Anti-inflammatory drugs

Limb elevation


Orthosis: Medial arch support (Functional foot orthosis)

Resistance cases: Doesn’t improve with a few weeks of conservative treatment



1. Surgical decompression and tenosynovectomy

2. Reconstruction of tendon/ tendon transfer

Spring ligament may require repair + Bony procedure

Calcaneal Osteotomy

Stage III, IV: Triple arthrodesis or Pantalar arthrodesis


Treatment :

1. Physiological Flatfoot: NO treatment

Corrects itself by 5-10 years

Some wear: Insole, footwear modification, molded heel cups

2. Tight Tendoachillis: Tendon stretching exercises

3. Accessory navicular: Orthosis

If significant flat: Tibialis posterior can be reinserted to navicular by drilling in it and suturing loop with the foot held in maximum insertion (Kidner’s Operation)

Rigid Flatfoot:

Initially conservative (Orthosis)

If symptoms still present, Resection of the calcaneal bar and filled with fat and muscle

If the coalition is > 50 % outcome after resection may not be effective

Then we go for,

  • Lateral Column Lengthening
  • Subtalar arthrodesis (degenerative changes) + Imbrication of talonavicular complex
  • Sliding calcaneal osteotomy