Pes Cavus

Synonym: claw foot

This condition is caused by an imbalance between the agonist and antagonist muscles in the foot. There is often family history and it is usually bilateral.
One in five cases is idiopathic; however, most are associated with neurological disorders.²

• Unilateral:
  • Cerebral palsy
  • Spinal cord tumour
  • Spina bifida
  • Tethered cord
• Bilateral:
  • Congenital
  • Polio
  • Charcot-Marie-Tooth syndrome³
  • Becker's muscular dystrophy
  • Friedreich's ataxia

Also associated with club foot or fractures.

There is often a range of other foot deformities also present, e.g. claw toes, increased calcaneal angle, 'cocked-up' big toe.

Symptoms

These vary with degree of deformity:

• Pain in side of foot and metatarsals
• Calluses on plantar aspect of foot
• Instability of ankle

Signs

• Inspect shoes for signs of abnormal wear.
• Observe gait for varus or foot drop.
• Perform neurological examination for possible underlying cause.

Take a full family history.

• X-ray of foot
• MRI of spine if tumour suspected
• Electromyography

General measures

• Physiotherapy to loosen tight muscles and improve strength of weak ones.
• Padding and orthotic shoes.

Surgical

• Depending on nature of deformity, can be release of plantar fascia, tendon transfer, osteotomy and arthrodesis.²
• Many need several operations.