Congenital
abnormalities
Congenital abnormalities in the foot can be divided into minor and major
abnormalities. Minor congenital abnormalities include many conditions which
are inherited. These abnormalities rarely cause significant problems. They
largely constitute toe abnormalities such as syndactyly or curly toes; these
variations are not uncommon and rarely need any treatment. Congenital hallux
varus is not common but can require surgery if severe or progressive. Hallux
valgus is surprisingly rare considering its incidence in the adult population.
Major abnormalities include genetic disorders, major chromosomal malformations,
and failure of formation or differentiation. In addition, there are several
conditions which, although present in the newborn child, do not fit into these
headings. They can be described as either structural or postural deformities.
Of
the major deformities clubfoot or talipes equinovarus is the commonest (Fig.
31.1). It has a familial incidence (one in 1000 live births reduces to one in 35
live births if one sibling is affected) and it has a varied incidence with
different ethnic groups (Maoris having the highest incidence). Although this
suggests a genetic propensity it seems likely there is a multifactorial mode of
inheritance. The exact mechanism of the production of the deformity is unknown;
it seems likely
Treatment
Treatment of talipes
equinovarus needs to commence within 24 hours of birth. Various techniques for
strapping or taping
The
remainder of the feet will require surgical correction. Although there is a
great deal of controversy about the exact timing of surgery, the extent of
surgery and the expected functional result, most authors would advocate that it
is undertaken during the first year of life. The aim of surgery is to achieve
the best functional result. By ensuring that the foot can be placed in
plantigrade (or flat to the floor) position this is likely to be associated with
the most satisfactory result. This will require an adequate posterior release to
allow the foot to dorsiflex actively at the ankle. The subtalar and midtarsal
joints need to be released to allow the primary rotational deformity to be
reduced. In many cases this will involve both medial and lateral releases.
Continued therapy and splintage should then back up the surgery, having achieved
adequate correction, during the first years of life. In particular, the weakness
of the peroneal tendons seen in many cases will not improve until at least 18
months of age. Children with this condition should be monitored throughout the
period of growth. The genetic propensity for the deformity is likely to continue
to be expressed throughout the growing period.
Other
major congenital deformities need treatment on their merits with the aim of
achieving the best functional result for the child.