The Cavovarus Foot



The cavovarus foot is a foot with a high arch that maintains its position on weight bearing.

Pathology can be found in the hindfoot, forefoot or both.

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Biomechanical consequences

  • The weightbearing area of the sole of the foot is reduced
  • Subtalar joint axis is more vertical
  • The talar head is externally rotated over the anterior process of the calcaneum
  • The subtalar and Chopart’s joint are more rigid
  • The foot is always “stiffer”
  • The ability of the foot to absorb impact is reduced



  • All forms of cavovarus foot essentially result from muscle imbalance
  • Brewerton (1963) found a subtle neurological cause in 66% of the 77 patients studied
  • 50% of all detectable lesions are a variant of Charcot Marie Tooth disease
  • Most “idiopathic" cases are likely to have a subtle neurological cause for the deformity below clinical detection
  • Always remember to look for correctable neurological pathology in the cavovarus foot (syrinx, spinal cord tumours)


Charcot Marie Tooth Disease

  • 50% of all detectable lesions causing a cavovarus foot
  • Jean Martin Charcot 1886
  • Tooth identified the peripheral nerve nature of the disease
  • Essentially a myelin sheath disorder; there are various types and inheritance, often with varying levels of penetration:

Type 1:           Commonest (50%) of all cases: autosomal dominant / sporadic

Type 2:           Next most common: autosomal dominant

Type 3:           X linked: 10-20% of cases

Type 4:           Rarest: autosomal recessive



Deformity vs muscle imbalance



  • Pain and symptoms
  • Family history
  • Progression
  • Uni- vs bi-lateral
  • Shoes
  • Treatment so far



Remember to do a full neurological exam; there is almost always a neurological condition as a cause and, if there is one detectable, 50% will be CMT

Look at the lumbar spine

  • Scars
  • Hair at the base of the spine
  • Scoliosis

In the unstable ankle, always look carefully for a (subtle) cavo varus deformity


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Note the abnormal pattern of wear on the flipflops! The cavo varus foot is the patient’s right foot.


The Coleman Block Test

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 Markedly varus heel, adducted forefoot

The outer border of the affected foot is placed on a 1cm board allowing the heel and the first ray to be free.

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 As the 1st ray drops down to the floor, the heel corrects to neutral / slight valgus = apparent correction of the forefoot adductus.


A positive Coleman block test confirms that

a) the subtalar joint is flexible and

b) at least part of the deformity is driven by a flexed first ray ("forefoot-driven") and this will need to be addressed to correct the deformity

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With the heel corrected to neutral, note the marked flexion/depression of the first ray. It is easy to understand that if this is not corrected, the first ray deformity will drive the heel into varus on standing.



“The goal - as in any foot surgery - is a plantigrade, comfortable foot”


Conservative treatment

  • UCBL Orthosis
  • AFOs
  • Physiotherapy / stretching


Surgical Treatment


  1. Where is the deformity?
  2. Hindfoot, forefoot or both?
  3. Is the deformity rigid or flexible?
  4. Can I balance the soft tissues or do I have to perform bony procedures?

Soft Tissue Procedures:

  1. Plantar fascia release (Steindler release)
  2. Tibials posterior tendon transfer (last muscle to fail in CMT)
  3. Peroneus longus to brevis tendon transfer (converts PL from a flexor of the first ray to a pure evertor of the foot)
  4. EHL transfer / tenodesis (Jones procedure combined with a fusion of the IPJ for claw hallux; also elevates the 1st ray)
  5. Flexor-extensor tendon transfer (FETT) procedure

Bone Procedures:

  1. Lateral heel shift / Dwyer osteotomy
  2. Proximal translation of calcaneum (Samilson, for polio)
  3. Extension osteotomy of the 1st ray
  4. Midfoot osteotomy
  5. Triple fusion

Surgery is based on careful preoperative assessment of the whole condition. It is best regarded as a palette of procedures applied to the individual patient's deformity.

One size does not fit all!


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Radiographs of a severe but flexible cavovarus foot treated with calcaneal osteotomy, extension osteotomy of the first ray and tibialis posterior tendon transfer

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Above: clinical photographs of left foot post-op (right pre-op) in a case of Charcot Marie Tooth disease. Treated with calcaneal osteotomy, extension osteotomy of the first ray, TA Lengthening and tibilalis posterior transfer into the lateral cuneiform (as TP was still working as a major deforming force)




Brewerton DA, Sandifer PH, Sweetnam DR. “Idiopathic” pes cavus: an investigation into its aeitiology. Br Med J.  2: 659-661 1963

Aminian A, Sangeorzan BJ. The anatomy of cavus foot deformity: Foot Ankle Clin. 13: 191-198 2008

Maskill MP, Maskill JD, Pomeroy GC. Surgical management and treatment algorithm for the subtle cavo varus foot. Foot Ankle Int. 2010;31(12): 1057-63

Samilson RL. Crescentic osteotomy os cslcis for calcaneovarus feet. Bateman JE Foot science. 1976 WB Saunders Philadelphia 18

Ward CM, Dolan LA, Bennett DL, et al.: Long term results of reconstruction for treatment of flexible cavovarus feet in Charcot-Marie Tooth disease. J Bone Joint Surg Am. 90:2631-2642 2008