Physicians who provide primary care for children from birth through adolescence encounter a variety of positional deformities of the legs and feet. The distinction between a pathological and functional cause must be made. The former should be referred to an orthopedist for treatment. When a pathological deformity of the legs or feet is diagnosed, the physician should look for other congenital anomalies, especially those involving the skeletal system.

The lower extremity rotates medially during the 7th fetal week, bringing the great toe to midline. With growth, femoral anteversion gradually declines from 30 degrees at birth to 10 degrees at maturity, leading to lateral rotation of the lower extremity during growth (Figure 183-1). Most functional deformities of the legs and feet are self-correcting in time, through this normal developmental progression of the lower extremity, even without treatment. This characteristic must be considered in weighing the results of any treatment prescribed. Studies of functional deformities, analyzing treated versus untreated paired control patients, have demonstrated the relative ineffectiveness of various treatments for these conditions, when analyzing treated versus untreated paired control patients. Therefore most clinicians choose to observe these conditions while children grow out of them.[3] [4] [5]

Figure 183-1 Positional deformities of the foot and ankle. A, Varus. B, Valgus. C, Equinus. D, Calcaneus. (Tachdjian MO. Pediatric Orthopaedics. Philadelphia, PA: WB Saunders; 1977. Copyright © 1977, Elsevier, with permission.)

Hallux valgus is a common problem. In a child with hallux valgus (Figure 183-2), the great toe is deviated laterally to overlap the second toe, and the first metatarsal bone is deviated medially, causing a prominence to form on the medial aspect of the metatarsophalangeal (MTP) joint. A bursa forms over the area as a result of the constant irritation and inflammation, forming a painful bunion. Some degree of foot pronation (flat feet) associated with the condition may be found.

Many factors come into play to cause the problem, including foot structure, which may or may not be hereditary, and use of narrow stylized shoes that crimp the toes. Most cases of hallux valgus are mild and asymptomatic and do not need treatment. Patients should be counseled in wearing shoes with plenty of toe room and no heels. If flatfoot is present, then a shoe insert to correct the foot pronation may help prevent progression of the disease. In the more severe cases, surgical correction may be needed.

Figure 183-2 Common toe anomalies.

Hammertoe occurs at the proximal interphalangeal joint (PIP) (see Figure 183-2). In an infant, hammertoe is usually hereditary; in the older child, it usually results from faulty shoe wear. Most cases of hammertoe are mild, cause no pain, and can be left alone. Parents should make sure that the child has roomy shoes that allow the toes to stretch. In the more severe cases, at an older age, surgical correction may be needed.

Mallet toe occurs at the distal interphalangeal joint (DIP) (see Figure 183-2). Most cases of mallet toe are mild and need no treatment. When a corn develops over the deformity, shaving and padding will help. In the more severe cases, surgical correction can be performed.

Claw toe involves all joints of the toe—hyperextension of the MTP joints and flexion at both the PIP and DIP joints (see Figure 183-2). Claw toe is a rare condition but usually occurs in conjunction with a cavus foot, present in neuromuscular diseases such as Charcot-Marie-Tooth disease or myelomeningocele.

In a child with a curly toe 4th or 5th toe is usually flexed downward and twisted underneath the adjacent toe (see Figure 183-2). Curly toe is quite common in infancy and childhood. If curly toe does not cause symptoms, then no treatment is needed; if the condition is severe and causes irritation with shoe wear, then surgical transfer of the toe flexor may correct the problem.

Polydactyly, the presence of an extra digit, usually the great toe or 5th toe (see Figure 183-2), may exist as an isolated finding or as part of a more extensive syndrome of congenital anomalies (5% of cases). The family history of the same anomaly is often found. If the extra toe is not causing problems with walking and shoe wear, then no treatment is needed. Vestigial digits can be ablated by suture ligation. If the duplication occurs in the little or big toe and sticks out prominently, then difficulty with shoe wear is common. In these cases, surgical excision will remove the problem. Surgery is typically performed after 9 to 12 months of age.

Syndactyly, the presence of webbed digits (toes) (see Figure 183-2), may also exist as an isolated finding or as part of a more extensive syndrome of congenital anomalies (5% of cases). A family history of the same anomaly is often found. Syndactyly is quite common and rarely causes problems. The interconnection between two or more toes can vary from thin skin to a bony attachment (synostosis) between parts of the phalanges. Unlike in the fingers, in which surgical separation is needed to obtain finer hand functions, syndactyly in the toes does not need treatment. The growth differential between the involved toes tends not to be significant.

Whereas a bunion forms on the great toe, the less common bunionette occurs at the fifth MTP joint. When a bunionette develops, the bursa over the lateral aspect of the fifth MTP joint gets prominent and inflamed and painful. If padding does not help relieve the discomfort of a bunionette, then surgical correction is needed.