Pediatric Foot and Ankle Disorders

Talipes equinovarus (TEV), or clubfoot, is a common disorder seen in roughly 1 in 1,000 live births. 40% are bilateral. TEV may result from intrauterine molding and be completely passively correctable, the so-called positional clubfoot, or it may be rigid.

Clubfeet may be associated with underlying disorders, such as myelomeningocele, Larsen syndrome, and Streeter dysplasia (constriction band syndrome) as well as other inherited conditions. It may be seen as an isolated condition (idiopathic). Initial treatment consists of ruling out associated conditions, followed by a course of nonoperative treatment with surgery reserved for recalcitrant cases.

Examination of a baby with TEV requires a thorough evaluation to rule out associated conditions. The spine, hips, and upper extremities should be closely inspected, as should the remainder of the lower extremity. A neurologic examination should be performed to rule out a paralytic clubfoot, as seen in spina bifida.

Concomitant lower extremity contractures suggest arthrogryposis. Examination of the foot entails evaluation of the forefoot (adduction), midfoot (cavus), hindfoot (varus and equinus), and the amount of internal rotation of the foot. The degree of deformity and its correctability should be determined.

Kite angles are most commonly used. These are the talocalcaneal angle measured on the anteroposterior and lateral radiographs. Because of the deformity of the foot, these radiographs should be taken with the beam aligned relative to the hindfoot.

In a clubfoot, the Kite angle is usually < 20° on the anteroposterior view and < 25° on the lateral view. In essence, the talus and the calcaneus are parallel rather than convergent.

While radiographs can be used to follow treatment results, there is significant variability in the measurements due to difficulty in positioning the foot, incomplete ossification of the bones of the foot, and difficulty determining the axis of the talus and calcaneus. Clinical examination of the foot must also be used to make treatment decisions.

The initial treatment of TEV is nonoperative. While many descriptions of manipulative treatment exist, the Ponseti method is the most commonly used.

Casts are applied every 5-7 days until the foot is corrected. First, the forefoot is supinated by dorsiflexing the 1st ray in order to eliminate the cavus deformity. Although the foot appears supinated in a clubfoot deformity, the 1st ray is actually pronated with respect to the hindfoot. Rather than pronating the foot, which is the basis of other treatment methods, supinating the foot allows the forefoot to align with the hindfoot. With a thumb applying pressure to the talus ( not the calcaneus), the foot is externally rotated and then gradually allowed to pronate in order to correct the varus. Finally, the foot is dorsiflexed. Applying a dorsally directed force without sufficient hindfoot flexibility may result in a break in the midfoot, the so-called rocker-bottom deformity.

Often, a percutaneous Achilles tenotomy is performed in the office to allow the foot to dorsiflex properly. When the foot is in the corrected position, the final cast is left in place for 3 weeks. Straight last shoes connected to a Denis Browne bar are then used full time for 3 months, followed by nighttime use until after walking age.

Given the primacy and overwhelming success of the Ponseti method, the surgical treatment of clubfeet is generally performed less now than it has been historically. Often, those patients that require surgery will be those who had insufficient treatment at a younger age. Not infrequently, in these patients, a trial of casting may be warranted in an effort to minimize the need for surgery.

The approach will vary depending on age of patient, prior treatment, and degree of deformity.

Surgery is best performed between 9-12 months of age. This allows proper visualization of anatomic structures, prevents extensive scarring seen with neonatal surgery, and allows the child to be weight bearing soon after surgery, which helps to maintain a plantigrade foot.

Systematic release of all involved structures is done until deformity is corrected.

A typical progression begins with a Cincinnati incision. The neurovascular bundle is identified and protected, followed by a release of the posterior ankle and subtalar joints. The foot is then assessed, and the medial portions of the joints released as well, taking care not to cut the deep deltoid ligament.

The foot is reassessed, and if needed, the talonavicular joint is opened, the spring ligament sectioned, and the navicular reduced. If significant cavus still exists, the plantar fascia can be released. Finally, if a bean shape is still present in the foot, a calcaneocuboid release can be performed.

Also included may be lengthening of the following tendons: Flexor hallucis longus, flexor digitorum longus, tibialis posterior, and Achilles. Care should be taken not to overlengthen the Achilles tendon.

Pinning of the talonavicular and subtalar joints may be required to maintain position in addition to casting. These are usually removed at 6 weeks, followed by an additional 6 weeks of walking casts. An ankle-foot orthosis may be used following casting in selected patients.

Recurrence of a clubfoot should prompt further investigation to rule out an underlying cause (i.e., tethered spinal cord).

The choice of procedure depends on the nature of the residual deformity. These secondary procedures are also often needed in the treatment of patients who present for treatment at an older age. The specific components of the recurrent clubfoot should be evaluated to design a surgical plan. Residual forefoot supination, hindfoot varus, internal rotation, equinus, or muscle weakness may all need to be addressed.

Transfer of the anterior tibial tendon to the midfoot may be helpful in addressing a dynamic supination deformity that is causing overload of the lateral column of the foot. Ponseti and colleagues routinely perform this procedure in patients who have undergone casting and have a residual dynamic supination deformity.

Weakness of the triceps surae from overlengthening of the Achilles tendon is difficult to overcome. Transfer of various tendons to augment plantar flexion has been described. Unfortunately, normal strength is usually not realized, emphasizing the importance of avoiding overaggressive Achilles lengthening.

Osteotomy is also a valuable tool. A residual bean shape of the foot can often be corrected via a lateral column shortening. Residual heel varus may be addressed with a Dwyer closing wedge osteotomy.

For severe residual deformity, gradually correcting the deformity using an external fixator may be helpful in avoiding neurovascular or skin compromise associated with rapid surgical correction.

Complications may include inadequate correction of the initial deformity, infection, ischemia with soft tissue loss, and others. The vascularity of the clubfoot is not normal. Often, the anterior tibial artery is hypoplastic or absent.

A dorsal bunion is seen when the peroneus longus is weakened or cut, leading to unopposed pull of the anterior tibialis combined with “overpull” of the toe flexors. Treatment involves realignment of the 1st ray through tendon release or transfer and osteotomy.

Subluxation of the navicular can be seen as well, arising from incomplete release or reduction of the navicular, or loss of fixation. Rereduction can be attempted in young children (i.e., < 6 years of age) if treatment for the resulting foot deformity is required.

Flatfeet are a common cause of concern for parents but usually require no treatment. Of primary importance is distinguishing painless, flexible flatfeet from painful or rigid feet.

A rigid flatfoot suggests the presence of a tarsal coalition, congenital vertical talus (CVT), or some other pathology. A painful flatfoot may be due to the above as well as an accessory navicular or an inflamed subtalar joint from inflammatory arthritis.

A good history is paramount. It is important to determine the reason for the visit (i.e., pain, deformity, grandmother’s insistence) as well as the onset of the deformity. If painful, the location of the pain is important.

Angular deformity of the lower extremity should be noted. Young children with physiologic valgus at the knee (3-5 years of age) will often appear flatfooted due to the more proximal deformity. This condition usually resolves as the valgus corrects spontaneously. A neurologic examination should be done to rule out increased muscle tone (i.e., spastic flatfoot) or other neuromuscular condition.

The examination of the foot should include the following: Presence of an equinus contracture, callus pattern, subtalar motion, arch at rest (non-weight bearing) and with toe raise.

A flexible flatfoot has a normal arch while sitting as well as with toe raise. During toe raise, the heel should be seen to move into varus as well. This is not the case with a rigid foot seen with a tarsal coalition. The Jack test consists of dorsiflexing the great toe, which should cause the arch to form in a seated patient.

If an accessory navicular is suspected, an oblique taken with the beam angled 45° medially may be obtained. CT scanning is helpful to rule out the presence of a tarsal coalition.

Unilateral foot deformities should prompt a thorough neurologic examination, and MR may be indicated to rule out a tethered cord, lipomeningocele, etc.

Treatment options include reassurance, Achilles stretching, arch supports, and surgery. For the majority of patients with flexible flatfeet, no treatment is needed. For those with a tight Achilles tendon, daily stretching may offer some benefit.

If the feet are painful from collapse of the arch and medial skin irritation, a cushioned arch support may be helpful. A more rigid insert is occasionally helpful for more severe feet, but many children do not tolerate a rigid orthosis.

Patients with intractable symptoms, despite maximized nonoperative treatment, may benefit from surgery. Arthroeresis, using silicone, silastic, or even metal implants placed through small incisions laterally, has received much attention, as it is an extraarticular, minimally invasive procedure. Although some success has been noted with this procedure, in the author's experience, failure occurs at an unacceptably high rate with pain from the implant &/or migration being consistent concerns.

As opposed to the adult flatfoot, tendinous and ligamentous pathology is typically not a component of the deformity, and so osteotomy (anterior or posterior calcaneal, 1st metatarsal) is often the procedure of choice. Hindfoot arthrodesis should generally be avoided given the poor long-term results with this procedure in young patients.