Cavus foot

What is a cavus foot ?

A cavus foot is an arched foot, with a very pronounced plantar arch or medial arch. Pressure is mainly applied at the heel and the forefoot pads. Hollow feet are rigid feet, which generally are not easily affected by shoes; they are often muscular, and tend to retract.

An asymptomatic cavus foot, causing no pain, does not require treatment or the use of orthopedic insoles.

What are the symptoms of a High Arched Foot?

The symptoms of a high-arched foot can be varied, with two symptoms coming to the forefront: pain and deformity of the foot or toes. The patient interview looks for a family history of high-arched feet and neurological disorders.

The clinical examination assesses the type of high-arched foot, its flexibility, and its reducibility. The hindfoot tends to turn inward, into varus, with shoe wear on the outer edge.

Plantar fasciitis and retraction of the posterior muscle chains

Plantar fasciitis is a classic symptom of high-arched feet. Schematically, the plantar fascia resembles a bowstring that tends to shorten, which can cause heel pain, pain in the sole of the foot, and all the way to the base of the toes. This plantar fasciitis can be part of a more global retraction of the Suro Achilléo Plantar system, causing calf cramps, pain in the Achilles tendons, and heel pain. Patients with high-arched feet often experience retraction of the posterior muscle chains, namely the gastrocnemius muscles.

Ligament and tendon injuries

The shape of a high-arched foot can lead to increased ligament tension on the outer side of the ankle and excessive stress on the peroneal muscles. High-arched feet can therefore be a contributing factor in sprains of the external ligament complex of the ankle during a traumatic inversion and equinus mechanism. Excessive use of the peroneal muscles can cause tendon inflammation in the peroneal tendons, called peroneal tenosynovitis or tenosynovitis of the fibular tendons, and promote the appearance of tendon injuries.

Metatarsalgia

Excessive pressure on the forefoot, increased by the retraction of the posterior muscle chains, can cause metatarsalgia, which means pain in the ball of the foot.

Toe deformity

The toes may show claw-like deformities, usually flexible, with retraction of the extensor tendons, and weakness of the flexor muscles and the foot's intrinsic muscles. Other deformities, such as a humped tarsus, may also be observed in some patients. This deformity can be compared to the shape of a cat's claws.

Neurological signs

During the clinical examination of a high-arched foot, it is essential to test muscular strength in the lower limbs. In the case of abnormal muscle weakness, it is necessary to consult a neurologist and perform an electromyogram to look for a neurological cause.

What are the causes of High Arch Foot?

High arches can be constitutional, without any particular cause. They can also be hereditary; a child will be more likely to have high arches if their parents also have high arches.

Several neurological conditions can be responsible for high arches and their worsening. Generally, both feet are affected, the deformities tend to worsen quickly, and the clinical examination reveals sensory and motor neurological disorders.

Which procedures to treat a Cavus foot?

There are several possible surgical interventions to treat a cavus foot. The surgical treatment depends on the patient's complaints, the cause of the cavus foot, its reducibility, and its flexibility. Surgical procedures for cavus feet are considered, except in the case of neurological cavus foot, when medical or functional treatment has failed.

Surgical interventions can range from a simple plantar fasciotomy to relieve plantar fasciitis to the architectural correction of the cavus foot by performing complex osteotomies such as tarsectomies.

Here are some examples of surgical interventions for cavus foot :

• In cases of flexible claw toe deformity, percutaneous tendon lengthening procedures may be suggested.
• Pain similar to metatarsalgia may be treated with metatarsal elevating osteotomies to relieve excessive pressure on the plantar pads.
• Excessive pressure under the head of the first metatarsal may be treated with a metatarsal elevating osteotomy, with or without plantar fascia lengthening in cases of anterior cavus foot.
• Ankle instabilities may require ligamentoplasties.
• Peroneal tendon injuries can be repaired.
• When hindfoot varus is significant, it may be necessary to perform a calcaneal valgus osteotomy, either alone or combined with a ligamentoplasty, peroneal tendon repair, or plantar fasciotomy.
• Architectural correction of the cavus foot is exceptionally proposed and may combine tarsectomy procedures and calcaneal osteotomy.

In the particular case of neurological cavus feet, the surgical treatment depends on the neurological deficit and the underlying condition. It includes tendon lengthening or transfer procedures, joint fusion, and osteotomies.

Which shoes or insoles to relieve a high arch?

It is difficult to recommend shoes or insoles to relieve a high-arched foot, as there are several types of high-arched feet.

If we consider all possible symptoms of a non-neurological high-arched foot, the shoe could be wide for rearfoot stability, with sufficient sole cushioning to relieve pressure points, and made from fairly soft leather to accommodate potential toe deformities.