What is Pediatric Foot Deformity?
Pediatric foot deformity is a term that includes a range of conditions that may affect the bones, tendons, and muscles of the foot. Among those most frequently treated at Hospital for Special Surgery (HSS) are cavus foot, tarsal coalition, clubfoot, accessory navicular, and juvenile bunion.
Treatment of foot deformities in children can vary significantly from that needed in adults. Fortunately, pediatric orthopedists who specialize in this field can bring to bear a range of non-operative and operative techniques specifically developed to address the distinctive needs of children, which include special attention to preserving the integrity of the growth plate, allowing continued growth and development of the foot.
Cavus foot is a condition in which the child has an excessively high arch. In many cases, the heel of the foot is turned inward; this is known as cavo-varus foot. The condition frequently affects both feet and is often progressive. Because the foot is not properly aligned, patients experience pain and develop calluses owing to uneven weight-bearing. Ankle sprains or even stress fractures may occur.
A cavo-varus foot that develops over time (as opposed to that which can appear with club foot) can indicate the presence of a neurologic problem, the presence of a cyst, or possibly a tumor in the spinal cord.
More commonly, however, it is the result of Charcot-Marie Tooth disease, a hereditary disorder in which the conduction speed of nerves slow over time and causes weakness of the distal muscles of the hands and feet. While Charcot-Marie Tooth disease is not life-threatening, the foot problems that accompany it can be disabling. In fact, because other symptoms may be mild or non-existent, the cavovarus foot may be the key to diagnosis.
Children with tarsal coalition develop an abnormal connection between the bones in the midsection and back part of the foot. It is usually diagnosed in late childhood or early adolescence when the coalition begins to limit foot movement, causing pain and sometimes stiffness. Symptoms may be particularly noticeable when walking on an uneven surface, such as sand or gravel, an action that requires constant adjustment of the foot. Frequent ankle sprains may also signal the presence of a coalition.
Most tarsal coalitions may be classified as one of two types: a calcaneonavicular coalition, in which the tissue develops between the calcaneus (heel bone) and the navicular (one of the foot bones), or a talocalcaneal or subtalar coalition, in which the coalition develops between the calcaneus and the talus (the ankle bone). The coalition may be composed exclusively of bone, a combination of bone and cartilage, or even fibrous tissue. Tarsal coalitions occur in both feet in about half of all cases.
Clubfoot describes a condition in which the foot—or sometimes both feet—are turned inward and are pointing down. Immediately apparent at birth, clubfoot is known to develop during intrauterine life, at between 9 and 14 weeks gestation. In fact, in many cases, the deformity is detected on routine ultrasound.
Occurring in about one in 1000 births, clubfoot is statistically seen more frequently in boys than in girls. And although family history may play a part, many infants with clubfoot have no known relative with the condition.
In the majority of cases, clubfoot can be successfully treated without surgery, using the Ponseti technique, which employs gentle manipulation and casting of the feet at weekly intervals. Treatment begins shortly after birth when the newborn’s foot, including tendons, ligaments, joint capsules and bones are most responsive. Following this first phase of treatment, a brace is used for an extended period to maintain proper alignment. When applied correctly, the Ponseti technique yields excellent results.
In some instances, clubfoot does require surgery—the approach that was used historically, before widespread acceptance of the Ponseti technique. While this approach can yield good correction of the deformity, the procedure may result in a stiff and arthritic foot later in life. When this occurs, additional surgeries may be necessary to alleviate the arthritic pain.
Accessory navicular describes the presence of an extra bone growth center on the inside of the navicular and within the posterial tibial tendon that attaches to the navicular. The primary symptom from this additional bony prominence is pain and tenderness.
This congenital defect (present at birth) is thought to occur during development when the bone is calcifying. Because this accessory portion of the bone and the navicular never quite grow together, it is believed that, over time, the excessive motion between the two bones results in pain.
The initial treatment approach for accessory navicular is non-operative. An orthotic may be recommended or the patient may undergo a brief period of casting to rest the foot. For chronic pain, however, the orthopedic surgeon removes the extra bone, a relatively simple surgery with a brief rehabilitation period and a very good success rate.
As with bunions in adults, in juvenile bunion, the joint at the base of the big toe (the metatarsophalangeal joint) moves out of alignment in such a way that the big toe angles inward to the second toe.
However, unlike adult bunion, which usually results from ill-fitting footwear or has a hereditary component, juvenile bunion occurs most often in children who are ligamentously lax or loose-jointed. The problem is more common in girls than in boys.
Surgical treatment for juvenile bunion is generally restricted until the end—or close to the end—of growth, both because of concern for damage to the growth plate and because the condition tends to recur. Non-operative treatment includes the use of wide shoes or sneakers and avoidance of narrow dress shoes and high heels. Usually this sufficiently alleviates symptoms to avoid or defer the need for surgery.
In younger patients who do not respond to non-operative treatment and who have pain that interferes with their daily activities, surgery to realign the bone and straighten the toe can be performed. A number of different approaches are used, depending on the type of bunion, the extent of the deformity, the age of the child, and how much growth remains.