Foot Problems in Children

Many feel that nearly all children and adolescents who
have a symptomatic accessory navicular become asymptomatic when they
reach skeletal maturity, suggesting that surgery should be delayed and
used only as a last resort. Use of a medial longitudinal arch support
may exacerbate the symptoms by adding more pressure to the region,
whereas a UCBL (University of California Biomechanics Laboratory) shoe
insert may unweight the painful area by bringing the heel into varus
and elevating the arch of the foot. Surgical excision of the accessory
navicular without re-routing of the posterior tibial tendon has been
reported to have good results.¹⁰ However, any surgery in a painful weight-bearing region of the foot is prone to continued discomfort (Fig. 25-5).

The os trigonum is a normal variant present in 13% of
children, where the flexor hallucis longus passes in the groove along
the posterior talus. The trouble with this accessory bone is that it
can fracture and cause pain or become symptomatic in ballet dancers
presumably due to prolonged weight bearing in equinus. A fractured os
trigonum may have a rough or sharp border along the talus, in contrast
to an unfused os trigonum with a smooth border (Fig. 25-6).

Although not really an accessory bone, the apophysis at
the base of the fifth metatarsal where the peroneus brevis attaches is
often confused with a fracture by the unknowing (Fig. 25-7).

It is hard to get in trouble with this condition as long
as you make the right diagnosis and don’t treat it. First, make certain
there is normal ankle dorsiflexion; if not, it is not metatarsus adductus (MTA), and may be a clubfoot. Look at the hindfoot; if there is significant valgus, think of a skewfoot (Fig. 25-10).
It may be difficult to differentiate between MTA and skewfoot with
radiographs in infants as the navicular is not yet ossified (Fig. 25-11). MTA may also be confused with a metatarsal longitudinal epiphyseal bracket (Fig. 25-12).

In the extraordinarily unlikely event that surgery is
needed for MTA, do not do a capsular release as this leads to poor
results. We recommend an osteotomy of the medial cuneiform, rather than
the first metatarsal, both to avoid the proximal physis of the first
metatarsal, and for better correction. Lateral osteotomies may be of
the second to fifth metatarsals or the cuboid.

First off, forget about the foot and look for an
underlying neurologic condition. It has been reported that two thirds
of patients with painful high arches have an underlying neurologic
problem that turns out to be Charcot-Marie-Tooth about 50% of the time.²³
If there are bilateral cavus feet, think of neuromuscular disease. If
the occurrence is unilateral, think of a spinal problem and order an
MRI of the entire spine. As a spine examination is not complete without
inspection of the feet, examination of a child with a cavus foot is not
complete without inspection of the spine. If the underlying
neuromuscular problem is treatable, get on with it before treating the
foot. Treatment for progressive cavus deformity with pain and
instability is surgical. Make certain the parents understand that the
foot deformity is not the problem, but is the result of the problem. It
is possible that future surgery will be needed, as the underlying
disease progresses in many cases.

This is an uncommon condition that is commonly
associated with underlying neuromuscular conditions or syndromes. The
surgeon’s first job is to identify those other conditions.

In the young infant, this deformity may not be quite as
obvious as some other foot deformities. A prominent talar head in the
setting of a rigid foot is suspicious, but avoid confusing an oblique
talus, positional calcaneovalgus, posteromedial bowing of the tibia, or
just a really flat foot, with a vertical talus (Fig. 25-13A).
By definition, a vertical talus is a fixed dorsal dislocation of the
navicular on the head of the talus. As the navicular is not ossified
until about age 3 years, and cannot be seen on plain radiographs, we
rely on the relationship of the axis of the talus and the first
metatarsal. The diagnosis is confirmed on the plantar flexed lateral
radiograph by observing that the axis of the talus passes plantar to
that of the first metatarsal (Figs. 25-13B and C).
Avoid the pitfall of believing that if the two axes become parallel,
there is not a vertical talus. Dorsal translation of the first
metatarsal axis in relation to that of the talus indicates dorsal
dislocation at the talonavicular joint (Fig. 25-14). The axis of the talus remains vertically aligned with the axis of the tibia on the dorsiflexion lateral radiograph.

Unlike clubfoot, casting is generally considered
unlikely to correct the vertical talus deformity, though Dr. Matthew
Dobbs in St. Louis has reported some success.

Preoperative plantar flexion casting will stretch the dorsal skin and tendons, thus facilitating surgical deformity correction.

Many series report a higher recurrence rate following
bunion surgery in adolescents than in adults. Stay out of trouble by
delaying surgery until skeletal maturity, if possible. If surgery is
needed, consider an opening wedge osteotomy of the medial cuneiform, if
the intermetatarsal angle is greater than 8 degrees. This will help
correct a medially deviated cuneiform-first metatarsal joint, as well
as avoid potential damage to the first metatarsal growth plate.

The first pitfall is making the correct diagnosis. The
diagnosis of a tarsal coalition should be strongly suspected from the
physical examination, based on decreased subtalar joint motion and
inability to voluntarily invert the foot (see Fig. 25-3). Many children with a tarsal coalition present with rigid heel valgus and tightness of the peroneal tendons (Fig. 25-16).

Standard AP and lateral radiographs may not always
clearly demonstrate tarsal coalitions, but they do provide lots of
clues. Oblique views are usually diagnostic of a calcaneonavicular
coalition, (Fig. 25-17) though a fibrous
coalition is best visualized on an MRI. A talocalcaneal coalition may
be seen on a Harris view if you are lucky enough to get a perfect shot,
but is most reliably seen on a CT scan (Figs. 25-17 and 25-18).
A recent series of 48 patients found the C-sign of Lateur on the
lateral radiograph to be present in all patients with flatfeet, but
present in only 40% of those with tarsal coalitions,²⁴ (Fig. 25-18)
so an absence of the C-sign does not rule out a tarsal coalition. A CT
scan should be considered for all feet in which a calcaneonavicular
coalition has been identified on plain radiographs because of the
possibility of a coincidental talocalcaneal coalition in the same foot.
A second coalition was identified in 20% of patients undergoing CT
scans for tarsal coalition at the Texas Scottish Rite Hospital, though
this population from a tertiary pediatric center may be skewed towards
more severe cases.²⁵

The majority of children and adults with tarsal
coalitions are asymptomatic, so the second pitfall here is in treating
something that doesn’t need treatment. Pain onset is usually between
ages 8 and 16 years in those who become symptomatic. The exact site(s)
and source(s) of pain in tarsal coalitions are not well established. A
few weeks of immobilization in a cast or walking boot may get a child
through a symptomatic period, and save the child from surgery.
Unfortunately, it is our experience that in most children who present
with painful tarsal coalitions, pain will return after immobilization,
and surgery is likely eventually.

At the time of surgery, be aware of how many coalitions
exist in the foot and have a plan for your approach to each. Recurrent
discomfort occurs at times due to inadequate resection, particularly of
the talocalcaneal coalitions. Make certain that adequate bone is
removed at the primary surgery so that normal cartilage and joint is
seen at the periphery of the resection, and full inversion of the heel
does not cause impingement at the region of resection. Last, but not
least, as with any operation to treat pain in the feet, make the
patient and family aware that pain relief cannot be guaranteed.

This is a very common deformity in newborns. Although
the appearance of the foot may be striking, spontaneous correction is
the rule (Fig. 25-19). Having the parents
perform stretching exercises may help the babies, and will keep the
parents happy that something is being done. The thing to watch out for,
on tests more than in real life, is the true diagnosis of posterior
medial bowing of the tibia, which usually corrects spontaneously but
may result in a 3- to 4-cm leg length discrepancy. See Chapter 10 on newborns for more discussion of this subject.

This condition is no trouble as long as you recognize it
and do not confuse it with infection, fracture, or something more
serious. Do not treat if there are no symptoms, but immobilization for
a few weeks should help relieve discomfort.

Multiple ossification centers of the navicular may be confused with Köhler disease (Fig. 25-20).

Polydactyly is common and usually an isolated finding,
although it can be associated with Ellis-Van Creveld syndrome, Down
syndrome and tibial hemimelia. Thus you should be on the lookout for
underlying disorders when encountering polydactyly.

In contrast, absent toes may signify an underlying
longitudinal deficiency, most commonly fibular hemimelia, and may be
associated with other conditions such as a leg length discrepancy, ball
and socket ankle, or absent ACL.

Syndactyly of the toes is rarely symptomatic, and can be
made much worse with surgery. Excessive scarring and unhappiness with
cosmetic appearance is not uncommon following surgical resection. But
don’t worry, plastic surgeons don’t read this book, so you may refer
patients who demand surgery to them.