Cavus foot. The cavus foot is one that has a medial longitudinal arch height higher than normal. This definition does not by itself imply a syndrome. Many causes can lead to this deformity. Pes cavus usually also presents other concomitant deformities, generally depending on the cause that caused it.
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- 1 Pathology
- 2 Clinical picture
- 3 Radiography
- 4 Treatment of pes cavus
- 5 Sources
Whatever the cause, known or idopathic, there appears to be a dysfunction of the intrinsic musculature of the foot. Certain degrees of pes cavus are common when the foot is exercised above normal; for example, in polio sequelae involving a single limb, a certain degree of cavus is usually found in the normal foot.
The same can be seen in child or juvenile single lower limb amputees. A sustained effort develops a very high and convex plantar arch. The exaggerated development of the plantar arch is usually accompanied by a relative shortening of the extensor muscles of the fingers, usually very powerful, that carry the fingers (metatarsophalangeal joint) in hyperextension, generating characteristic claw toes.
As the plantar arch is raised, the insertion points of the plantar fascia are brought closer: the foot becomes shorter. In the plantar footprint there is an overload in the forefoot. A failure of the forefoot ligaments quickly occurs. There is pain (metatarsalgia) and calluses appear due to overuse. The shortening of the plantar fascia possibly forces a varus displacement of the calcaneus. This varus shift is constant in idiopathic and some neuropathic pes cavus.
The patient complains of pain. The pain corresponds to metatarsalgia. You have difficulty finding suitable footwear because your instep does not fit. In the podoscope or pedigraphy, an overload of the heel is seen, or no lateral border and especially hyperpressure in the forefoot.
In the adolescent cavus idopathic foot, only an exaggerated height of the plantar arch is appreciated with normal bone morphology. If it is a polio sequela, there is usually an abnormal position of the calcaneus, which further develops its posterior portion, very verticalized, taking on the typical “revolver butt” appearance. The talus is always very horizontal and the calcaneal-talus angle (in frontal projection) is greatly diminished. In special projections the varus deviation of the calcaneus is verified.
Treatment of pes cavus
The development of a certain cavus foot is expected with age in normal people, especially women. These feet are within the normal limits radiologically, however they are usually painful in the metatarsus. Metatarsalgia will be fought with insoles that unload the front of the foot.
If calluses already exist, the templates will have a special design according to the position of the hyperpressure zones. In the idiopathic adolescent pes cavus, there is a progression of the deformity that cannot be treated with conservative means such as templates.
Treatment is usually surgical: tendon transposition; calcaneal osteotomy; to correct the varus; midfoot osteotomies, etc. Neuropathic cavus feet are usually treated surgically. But after the intervention, they will often have to use previous download templates. In many cases, footwear must be modified to allow the back of the foot (instep) to accommodate.