Metatarsus adductus is common in newborns and involves adduction of the forefoot relative to the hindfoot. When the forefoot is supinated and adducted, the deformity is termed metatarsus varus (Fig. 666-1). The most common cause is intrauterine molding, where the deformity is bilateral in 50% of cases. As with other intrauterine positional foot deformities, a careful hip examination should always be performed.

Figure 666-1 Clinical picture of metatarsus adductus with a normal foot on the opposite side.

Talipes equinovarus (also known as clubfoot) describes a deformity involving malalignment of the calcaneotalar-navicular complex. Components of this deformity may be best understood using the mnemonic CAVE (cavus, adductus, varus, equinus). Although this is predominantly a hindfoot deformity, there are plantar flexion (cavus) of the 1st ray and adduction of the forefoot/midfoot on the hindfoot. The hindfoot is in varus and equinus. The clubfoot deformity may be positional, congenital, or associated with a variety of underlying diagnoses (neuromuscular or syndromic).

The positional clubfoot is a normal foot that has been held in a deformed position in utero and is found to be flexible on examination in the newborn nursery. The congenital clubfoot involves a spectrum of severity, while clubfoot associated with neuromuscular diagnoses or syndromes are typically rigid and more difficult to treat. Clubfoot is extremely common in patients with myelodysplasia and arthrogryposis (Chapter 674).

Congenital clubfoot is seen in approximately 1/1,000 births. Although numerous theories have been proposed, the etiology is multifactorial and likely involves the effects of environmental factors in a genetically susceptible host. The risk is approximately 1 in 4 when both a parent and one sibling have clubfeet. It occurs more commonly in males (2 : 1) and is bilateral in 50% of cases. The pathoanatomy involves both abnormal tarsal morphology (plantar and medial deviation of the head and neck of the talus) and abnormal relationships between the tarsal bones in all three planes, as well as associated contracture of the soft tissues on the plantar and medial aspects of the foot.

Clinical Manifestations

A complete physical examination should be performed to rule out coexisting musculoskeletal and neuromuscular problems. The spine should be inspected for signs of occult dysraphism. Examination of the infant clubfoot demonstrates forefoot cavus and adductus and hindfoot varus and equinus (Fig. 666-2). The degree of flexibility varies, and all patients exhibit calf atrophy. Both internal tibial torsion and leg-length discrepancy (shortening of the ipsilateral extremity) are observed in a subset of cases.

Figure 666-2 Clinical picture demonstrating talipes equinovarus.

Congenital vertical talus is an uncommon foot deformity in which the midfoot is dorsally dislocated on the hindfoot. Approximately 40% are associated with an underlying neuromuscular condition or a syndrome (Table 666-1); although the remaining 60% had been thought to be idiopathic, there is increasing evidence that some of these may be related to single gene defects. Neurologic causes include myelodysplasia, tethered cord, and sacral agenesis. Other associated conditions include arthrogryposis, Larsen syndrome, and chromosomal abnormalities (trisomy 13-15, 19). Depending on the age at diagnosis, the differential diagnosis might include a calcaneovalgus foot, oblique talus (talonavicular joint reduces passively), flexible flatfoot with a tight Achilles tendon, and tarsal coalition.