• Pes cavus is a foot with a high longitudinal arch
•  It is often associated with clawing of the toes and a varus hindfoot.
• It is not a single disease entity.
• It has a wide spectrum of clinical problems and presentations which may need different approaches and types of treatments.
• There are various underlying conditions
• Two thirds have neurological problems.

Clinical photograph of a child with pes cavus.

• There are 4 types of pes cavus: Cavo-varus (commonest), Calcaneo-cavus, Calcaneus and Plantaris.
• Rang’s tripod theory depicted the foot as a balanced tripod (the calcaneum, the first and the fifth rays)
• Muscle imbalance (or other causes) causes one or more of tripod limbs to change position.
• To resume balance, our body forces the other limbs to change and touch the floor. This usually creates a high arch foot
• For example, if the first ray is plantar-flexed, the three points can only rest on the ground if the hindfoot tips into varus causing cavo-varus foot
• The same would happen if muscle imbalance led to a varus heel.

Types of pes cavus: cavo-varus (commonest), Calcaneo-cavus, Calcaneus and Plantaris. These can overlap.

To depict various types of pes cavus: Rang simulate foot to a tripod.

• Congenital:

1. Idiopathic
2. CTEV
3. Arthrogryposis

• Acquired:

• Trauma
• Neuromuscular:

1. Muscular dystrophy
2. HSMN
3. Polio
4. Spinal cord disorders (spina bifida, spinal dysraphism)
5. Friedrich’s ataxia
6. Cerebral palsy

The tripod theory explaining the various types of Pes Cavus.

• The diagnosis is usually clinical and should include a full neurological assessment.
• Examination of the hand (wasting of the intrinsic muscles is noted in HSMN.
• A Coleman block test is required to assess if the hindfoot varus is correctible.
• Standing radiographs of the foot help document the severity of the deformity (see figure 4.5.4 and 4.5.5).
• Nerve conduction study, MRI of the brain and spine may be required to establish the cause, particularly in recent honest or unilateral cases.

Coleman test showing the heel varus remain despite allowing the first ray to drop on the side of the standing board.

Asymptomatic patients do not usually require treatment.
On the other hand, pes cavus can produce a wide spectrum of symptoms:

• Toe deformity rubbing on shoes.
• painful calluses under the metatarsal heads caused by forefoot plantar flexion and fixed toe deformity.
• Lateral foot pain and painful calluses on the lateral foot border due to hindfoot varus.
• Walking difficulty due to foot deformity or foot drop.
• Foot wear problems due to deformity.
• Ankle instability due to hindfoot varus and peroneus brevis weakness.
• Worries about progression.

The aim of treatment is to relieve symptoms and correct deformity.

• Physiotherapy has a limited role.
• Orthoses may help alleviate symptoms but do not reverse deformity.
• Surgery aims are to achieve a pain-free, plantigrade, supple but stable foot.

Surgical intervention could involve a combinations or all of the followings depending on the severity:

• Release of the plantar fascia.
• Closing-wedge dorsiflexion osteotomy of the first (± second) metatarsal.
• Calcaneum lateral sliding and closing-wedge osteotomy,
• Transfer of the peroneus longus into the peroneus brevis at the level of the distal fibula.
• Achilles tendon lengthening.
• Clawing of the toes is improved by extensor tendon lengthening or tenotomy.
• Jones procedure (extensor hallucis longus tendon transferred to the first metatarsal) with IPJ tenodesis or arthrodesis
• Midfoot dorsal closing wedge osteootmy
• Triple arthrodesis

A child with pes cavus, treated with tendoachillis lengthening and mid-foot dorsal wedge closing osteotomy.