Foot Disorders

Calcaneovalgus Foot

Calcaneovalgus foot is generally considered a uterine-packing problem in which the foot is markedly dorsiflexed at birth so the dorsum of the foot sits against the anterior surface of the tibia. The hindfoot is usually in moderate eversion (valgus) as well. Although some flexibility is present with the deformity, there is resistance to full motion, and most cases do not allow ankle plantar flexion beyond a right angle.

Despite its dramatic appearance, calcaneovalgus foot corrects spontaneously within 2–3 months. Although some orthopedists brace or apply serial casts and many recommend stretching exercises, all true calcaneovalgus feet resolve without treatment.

Congenital Vertical Talus

Calcaneovalgus foot must be differentiated from a much rarer condition known as congenital vertical talus (congenital rocker-bottom foot, congenital complex pes valgus). In this deformity, although the foot appears to lie against the anterior tibia, the hindfoot is actually plantar flexed because of contracture of the posterior calf muscles. To accommodate plantarflexion of the hindfoot and dorsiflexion of the forefoot, the midfoot joints (talonavicular and calcaneocuboid joints) must subluxate or dislocate dorsally.

Congenital vertical talus often accompanies genetic disorders, syndromes such as arthrogryposis, or neuromuscular disorders such as spina bifida. It is occasionally found in otherwise normal infants, however. Treatment is usually surgical, and casting does not resolve the disorder.

Cavus Foot

Cavus foot is a foot with an abnormally high arch. Although it is difficult to ascribe a particular threshold of arching beyond which treatment is necessary, most deformities are dramatic enough to make diagnosis straightforward

Cavus foot frequently accompanies hindfoot varus deformity (cavovarus foot), and there may be clawing of the toes and demonstrable weakness of ankle or foot muscles. In addition, calluses beneath the metatarsal heads and heel skin are common.

Clinical Findings

One of the most common symptoms of cavus foot is anterior ankle pain, sometimes associated with toe walking. This paradoxical situation occurs because of the pathologic anatomy of the cavus foot. The forefoot is severely plantar flexed on the hindfoot, requiring marked ankle dorsiflexion to compensate. When the cavus becomes too severe, ankle dorsiflexion is blocked, leading to anterior ankle impingement and pain. The inability to dorsiflex further compromises forefoot clearance, and, eventually, only the metatarsals can contact the floor. This can be misinterpreted as ankle plantarflexion contracture, leading to unnecessary (and possibly harmful) heel cord release.

The cause of cavus foot is usually muscle imbalance in a growing foot. Thus, cavus is rarely found in early childhood but is fairly frequent after 8–10 years of age. Although intrinsic muscle weakness is a major cause of cavus foot, weakness of the peroneal or anterior tibialis muscles is also implicated. Cavus foot is rarely found in the absence of an underlying neuromuscular condition.

Cavus foot is a marker for neuromuscular disease. Diagnosis requires a thorough search for the underlying cause and may require neurologic consultation, spinal MRI, and electromyographic (EMG) studies. Table 11–6 lists common neuromuscular causes of cavus foot.

Table 11–6. Common Neuromuscular Causes of Cavus Foot.


Cerebral palsy
Charcot-Marie-Tooth disease
Compartment syndrome
Diastematomyelia
Friedrich ataxia
Muscular dystrophy
Spinal cord tumor
Spinal dysraphism (spina bifida)

Treatment

Conservative treatment of cavus foot includes accommodation by shoe modifications or inserts. These modalities do not actually correct the condition; severe deformity requires surgical correction by tendon transfers to restore muscle balance, by midfoot osteotomy to correct bony deformity, or by triple arthrodesis (hindfoot fusion in a corrected position).

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