Cavus Foot

On this page

Cavus Foot: Definition & Anatomy - High Arches, Hidden Issues

  • Definition: Complex foot deformity with an abnormally high medial longitudinal arch; can be flexible or rigid.
  • **Key Anatomical Features (Triplanar Deformity):
    • Hindfoot: Varus (most common), ↑ calcaneal pitch angle.
    • Midfoot: Adduction, plantarflexion of first ray (creates cavus).
    • Forefoot: Adduction, pronation (compensatory), claw toes (MTPJ extension, IPJ flexion).
  • Terminology: Pes cavus, talipes cavus, high-arched foot. Normal vs. Cavus Foot Anatomy

⭐ The Coleman block test is essential to differentiate between forefoot-driven and hindfoot-driven cavus, guiding treatment decisions by assessing hindfoot flexibility when the first metatarsal is allowed to drop off the edge of a block.

Cavus Foot: Etiology & Pathomechanics - Why the Arch?

  • Etiology (Often Neuromuscular):
    • Neurological (Most Common):
      • Charcot-Marie-Tooth (CMT) (📌 Cavus Mostly Together)
      • Friedreich's Ataxia, Spinal Dysraphism, Polio
    • Other: Trauma (e.g., compartment syndrome, malunion), Congenital, Idiopathic
  • Pathomechanics (Muscle Imbalance):
    • Forefoot Driven: Peroneus Longus (PL) overpowers Tibialis Anterior (TA) → 1st ray plantarflexion.
    • Hindfoot Driven: Tibialis Posterior (TP) overpowers Peroneus Brevis (PB) → Hindfoot varus.
    • Intrinsic Imbalance: → Claw toes.
    • Result: ↑ Arch, rigid foot, ↓ shock absorption. Cavus vs Normal Foot Comparison

    ⭐ The Coleman block test helps differentiate flexible hindfoot varus (corrects with block) from rigid hindfoot varus in cavus foot, guiding surgical planning by assessing forefoot-driven deformity contribution to hindfoot varus.

Cavus Foot: Clinical Assessment - Spotting the Signs

  • History: Onset (congenital/acquired), progression, pain (location, character), instability, family history (e.g., Charcot-Marie-Tooth disease), footwear issues.
  • Observation:
    • High arch (medial longitudinal).
    • Hindfoot: Varus ("peek-a-boo" sign), increased calcaneal pitch.
    • Forefoot: Adduction, pronation, plantarflexed 1st ray.
    • Toes: Clawing. Callosities (lateral border, metatarsal heads).
  • Gait: Lateral weight-bearing, ankle instability.
  • Key Tests:
    • Coleman Block Test: Assesses hindfoot flexibility.
    • Thorough neurological examination (essential for etiology).

⭐ The Coleman block test is crucial: it differentiates a flexible hindfoot (corrects with block under lateral forefoot) from a rigid deformity, guiding surgical strategy.

Cavus Foot: Imaging & Classification - X-Ray Vision

  • X-Rays (Weight-Bearing):
    • Lateral View:
      • ↑ Meary's Angle: > (Talus-1st MT) - apex dorsal.
      • ↑ Hibb's Angle: >45° (Calcaneus-1st MT).
      • ↑ Calcaneal Pitch: >30°.
    • AP View:
      • ↓ Kite's Angle (Talocalcaneal): <20° (hindfoot varus).
  • Coleman Block Test: Differentiates flexible forefoot-driven hindfoot varus. Lateral X-ray of cavus foot with Meary's angle
  • Classification: Based on radiographic angles (severity) & deformity apex.

    ⭐ Meary's angle (talus-1st metatarsal) is key for identifying apex and severity of cavus deformity on lateral X-ray.

Cavus Foot: Management Principles - Fixing the Foot

  • Conservative: Stretching exercises, custom orthotics (e.g., UCBL, lateral wedge for forefoot/hindfoot), appropriate footwear modifications.
  • Surgical Goals: Relieve pain, improve stability, correct deformity.
    • Flexible Deformity: Plantar fascia release, tendon transfers (e.g., Peroneus Longus to Brevis, Hibbs).
    • Rigid Deformity: Bony procedures.
      • Osteotomies: Calcaneal (Dwyer), metatarsal (dorsiflexion).
      • Arthrodesis: For severe, arthritic joints (e.g., triple arthrodesis).
    • Apex of deformity guides surgical choice.

Lateral X-ray of surgically corrected cavus foot

⭐ The Coleman block test helps differentiate forefoot-driven cavus (plantarflexed first ray) from hindfoot-driven cavus, guiding surgical strategy.

High‑Yield Points - ⚡ Biggest Takeaways

  • Cavus foot: high-arched foot, often from neuromuscular disorders (e.g., Charcot-Marie-Tooth).
  • Symptoms: painful callosities (metatarsal heads), claw toes, ankle instability, hindfoot varus.
  • Coleman block test: crucial for assessing hindfoot flexibility and differentiating forefoot vs. hindfoot driven deformity.
  • Radiographs: ↑ calcaneal pitch, ↑ Meary's angle, abnormal Hibb's angle.
  • Treatment: orthotics initially; surgery (osteotomies, tendon transfers) for severe cases.
  • Investigate for neurological causes (e.g., spinal dysraphism), especially if unilateral.
Rezzy AI Tutor

Have doubts about this lesson?

Ask Rezzy, our AI tutor, to explain anything you didn't understand

Practice Questions: Cavus Foot

Test your understanding with these related questions

Which type of intra-articular fracture of the calcaneum is characterized by an increased Gissane's angle?

1 of 5

Flashcards: Cavus Foot

1/8

Hallux valgus leads to overriding of the _____ finger and prominence of the 1st MTP head

TAP TO REVEAL ANSWER

Hallux valgus leads to overriding of the _____ finger and prominence of the 1st MTP head

2nd

browseSpaceflip

Enjoying this lesson?

Get full access to all lessons, practice questions, and more.

Start For Free