• Clinical science

Foot deformities

Summary

Foot deformities are a heterogeneous group of congenital and acquired conditions involving structural abnormalities or muscular imbalances that affect the function of the foot. The deformities are classified according to clinical appearance. The most recognizable congenital foot deformity is the clubfoot deformity, which is characterized by plantar flexion of the ankle, inversion of the foot, and adduction of the forefoot. Manipulative treatment of congenital foot deformities, which requires manual repositioning and serial casting, should be initiated immediately after birth. The outcome depends primarily on whether the deformity responds well to manual repositioning (flexible deformities). Resistant deformities often require surgical correction.

Overview

Foot deformity Etiology Characteristics Therapy
Club foot
  • Congenital (common) or acquired (rare)
  • Differential diagnosis: postural clubfoot
  • Bilateral in 30–50% of cases
  • Mechanism
  • Deformity: foot points downwards and inwards
    • Hindfoot equinus and varus
    • Midfoot cavus
    • Forefoot adductus
    • Limited dorsiflexion
  • Diagnosis
    • Clinical diagnosis (prenatal detection via ultrasound possible)
    • X-ray (can confirm clinical diagnosis): long axis of talus and calcaneus are parallel
  • Manual repositioning and serial casting immediately after birth
  • If manual repositioning is unsuccessful: surgical release of contractures and correction of bone alignment
Pes cavus
  • Congenital or acquired
  • High longitudinal arch
  • Hindfoot varus
  • Physiotherapy, orthotics
  • If conservative measures are unsuccessful: surgical correction
Metatarsus adductus
  • Idiopathic but associated with hip dysplasia
  • Differential diagnosis of in-toeing: internal tibial torsion, femoral antetorsion
  • In-toeing
  • The deformity may be flexible or rigid
  • X-ray: increased angle between the 1st and 2nd metatarsal bones
  • Most common cause of in-toeing in children < 1 year of age
  • Rarely requires treatment and resolves spontaneously in > 95% of cases within the first 18 months of life
  • For severe cases (rigid deformity, passive correction impossible): casting
Splay foot
  • Acquired
  • Orthotics that support the ball of the foot
Calcaneal spur
  • Idiopathic
  • Risk factors: abnormal strain, obesity, foot deformities

References:[1][2][3][4][5][6][7][8][9]

Diagnosis and treatment of foot deformities

Diagnosis

  • Complete evaluation of feet, knees, hips, and spine
  • Flexible vs. resistant foot deformities
    • Evaluation of foot deformities, according to whether the deformity may be corrected with active (muscular contraction) or passive (manual correction by examining physician) manipulation.
      • Resistant deformity: difficult or impossible to correct → indicates a structural abnormality
      • Flexible deformity: may be easily corrected → indicates a muscular imbalance
  • X-ray: evaluate skeletal deformities

Basic principles of treatment

  • Correctable foot deformities: foot orthotics and manipulative treatment with casting and splinting are usually successful
  • Resistant foot deformities: surgical correction is usually required to reposition structures or relieve muscle contractures

Prompt treatment of congenital foot deformities is vital! Surgery may often be avoided if the manipulation is implemented correctly and consistently! If muscular imbalances are not corrected at an early age, they may result in structural deformities and often require surgery!

References:[10]

Clubfoot (talipes equinovarus)

  • Definition: Clubfoot is a complex foot deformity that is comprised of five fixed deformities.
    • Hindfoot
      • Equinus foot position: short Achilles tendon fixes the foot in plantar flexion
      • Varus position = supination of the calcaneus
    • Forefoot
      • Adductus; (Pigeon toe, false clubfoot, metatarsus adductus): medial deviation of the toes (adduction of the forefoot)
      • Supinatus: inversion of the forefoot
    • Cavus (high arch): distinct arching of the foot
  • Epidemiology
    • One of the most common congenital anomalies (∼ 1/1000 births)
    • Bilateral involvement in ∼ 50% of cases
  • Etiology
    • Congenital: most common form
    • Acquired: rare (e.g., secondary to neurological conditions or trauma)
  • Pathogenesis
    • Dominant medial musculature; posterior tibial muscle is considered to be the muscle primarily responsible for the clubfoot (→ plantar flexion and supination, particularly of the hindfoot)
    • Medial deviation of the talar neck
    • Weak peroneus muscles
    • Shortened Achilles tendon
  • Diagnostics
    • Physical examination: See “Diagnosis and treatment of foot deformities” above.
    • X-ray: The long axes of the calcaneus and talus are parallel.
  • Differential diagnosis: postural clubfoot
  • Complications: pathological strain with ulceration and early onset of arthrosis
  • Treatment
    • Manipulative treatment: the Ponseti-method (manual correction with serial casting ) should be initiated within 24 hours of birth
    • Achilles tenotomy: the equinus foot position may be corrected by surgically by lengthening the Achilles tendon with a Z-shaped suture

Manipulative treatment should begin within 24 hours of birth!

References:[1][6]

Splayfoot (pes planotransversus, pes transversoplanus)

  • Definition: spreading apart of the metatarsal bones with subsequent lowering of the metatarsal heads
  • Epidemiology: most common foot deformity
  • Etiology: muscular and connective tissue weakness (worsened by unsupportive footwear)
  • Clinical features
    • Metatarsalgia: pain in the metatarsal bone joints II–IV → abnormal strain on the metatarsal heads II–IV → painful callus .
    • Hallux valgus and digitus quintus varus: malalignment of the first and fifth ray
  • Complication: Morton metatarsalgia (Morton neuroma)
    • Sudden, shooting pain on the plantar side of the foot (between the 3rd and 4thmetatarsal)
      • Affected areas are innervated by the common plantar digital nerves (of the medial and lateral plantar nerves of the tibial nerve)
      • Typical signs
        • Mulder sign
          1. The forefoot is held firmly with one hand in the medial-lateral direction.
          2. Pressure is applied to the sole of the foot between the metatarsal heads (at the location of symptoms).
          3. If pain is perceived (especially on the plantar side), it indicates Morton neuroma.
            • This maneuver may also produce a “click” or snapping sensation, which is known as Mulder's click.
        • Tinel sign
  • Diagnostics
    • Physical examination: See “Diagnosis and treatment of foot deformities” above.
    • X-ray:
      • Spreading apart of the metatarsal heads
      • Erosion of the second to fourth metatarsal heads
      • Malalignment of the first and fifth ray
  • Treatment:
    • Orthotics that support the ball of the foot and provide plantar support to the metatarsal heads
    • Training of the foot muscles

References:[11][7]

Metatarsus adductus, curved foot (metatarsus varus)

  • Definition: adduction of the forefoot
  • Etiology: : unclear; presents immediately at birth
    • Increased risk in cases of intrauterine malposition
    • Association with hip dysplasia
  • Pathogenesis: a muscular imbalance between the adduction muscles and fibularis muscles is suspected to be the underlying cause
  • Clinical features
    • In-toeing of forefoot
    • Usually painless
    • Cases with high angles of adduction deformity (i.e., increased curvature of the forefoot, increased amount of in-toeing) may present with a medial skin crease over the forefoot
  • Diagnostics
    • Physical examination: See “Flexible vs. rigid foot deformities” above.
    • Gentle palpation of the lateral aspect of the foot → active correction of the deformity → indicates a mild correctable foot deformity
  • Differential diagnoses
    • Tibial torsion
    • Femoral anteversion
  • Treatment
    • Flexible curved feet do not usually require treatment.
    • Rigid curved feet or flexible curved feet that do not reposition spontaneously require conservative treatment.
      • Splintage and casting to correct the position of the foot
      • Orthotics and inserts
    • Surgery is required in cases that do not respond sufficiently to conservative treatment.
      • Reduction osteotomy of the cuboid bone (lateral ray is shortened) or wedge-insertion osteotomy of the cuneiform bone (medial ray is lengthened)

References:[3][7]