Congenital Foot Deformities in Children

What You Need To Know

Understanding congenital foot deformities and how they may affect your child.

Pediatric Congenital Foot Conditions

The accessory navicular (os navicularum or os tibiale externum) is an extra bone or cartilage located on the inner side of the foot just above the arch. It is incorporated within the posterior tibial tendon, which attaches in this area and can lead to what is called Accessory Navicular Syndrome. An accessory navicular is congenital (present at birth) and is not part of normal bone structure.

Many people with an accessory navicular are unaware of it if it causes no problems. However, some develop a painful condition when the bone or posterior tibial tendon become aggravated. This can result from trauma such as a foot or ankle sprain, chronic irritation from footwear rubbing against the extra bone, or excessive activity and overuse.

Signs and symptoms include a visible bony prominence on the midfoot, redness and swelling of that prominence, and vague pain or throbbing in the midfoot and arch during or after activity. Many children with this condition also have flat feet (fallen arches), which puts more strain on the posterior tibial tendon and can produce inflammation or irritation.

Adolescence is a common time for symptoms to first appear, as bones are maturing and cartilage is developing into bone. Sometimes symptoms do not occur until adulthood. If your child is showing signs of foot pain or a bony bump on the arch, an evaluation with our team can confirm the diagnosis and outline a plan for relief.

Diagnosis and Treatment Options

To diagnose accessory navicular syndrome, your doctor will ask about symptoms and examine the foot, looking for skin irritation or swelling. The doctor may press on the bony prominence to assess for discomfort. Foot structure, muscle strength, joint motion, and the way the patient walks may also be evaluated. X-rays are usually ordered to confirm the diagnosis, and an MRI or other advanced imaging may be used if pain or inflammation persists.

The goal of nonsurgical treatment is to relieve symptoms. Immobilization in a cast or removable walking boot allows the affected area to rest and decreases inflammation. Ice applied with a thin towel between the pack and the skin can reduce swelling. Oral nonsteroidal anti-inflammatory drugs such as ibuprofen may be prescribed, and in some cases oral or injected steroid medications may be combined with immobilization.

Physical therapy may be prescribed to strengthen the muscles and decrease inflammation, and may also help prevent recurrence. Over-the-counter or custom orthotic devices that fit into the shoe provide arch support and may help prevent future flare-ups.

If nonsurgical treatment fails to relieve symptoms, surgery may be appropriate. Surgery may involve removing the accessory bone, reshaping the area, and repairing the posterior tibial tendon. This extra bone is not needed for normal foot function, and most children return to comfortable activity once healing is complete.