Accessory Ossicle Navicular Pain

Overview
An accessory navicular is an extra bone that is on the inner center arch of the foot. Up to 2.5% of individuals are born with the accessory navicular. Throughout early childhood, this condition is not noticed. However, in adolescence, when the accessory navicular begins to calcify, the bump on the inner aspect of the arch becomes noticed. For most, it is never symptomatic. However, for some, there is some type of injury, whether a twist, stumble, or fall, that makes the accessory navicular symptomatic.



Causes
This can result from any of the following. Trauma, as in a foot or ankle sprain. Chronic irritation from shoes or other footwear rubbing against the extra bone. Excessive activity or overuse. Many people with accessory navicular syndrome also have flat feet (fallen arches). Having a flat foot puts more strain on the posterior tibial tendon, which can produce inflammation or irritation of the accessory navicular.

Symptoms
Perhaps the most common of the extra bones in the foot, the accessory navicular bone is estimated to be present in 7 to 19 percent of the population. Zadek and Gold maintained that the bone persisted as a distinct, separate bone in 2 percent of the population. Also be aware that the accessory bone normally fuses completely or incompletely to the navicular. It is this incomplete fusion which allows for micromotion, which, in turn, may cause degenerative changes that can also contribute to the pain.

Diagnosis
To diagnose accessory navicular syndrome, medical staff ask about the patient?s activities and symptoms. They will examine the foot for irritation or swelling. Medical staff evaluate the bone structure, muscle, joint motion, and the patient?s gait. X-rays can usually confirm the diagnosis. MRI or other imaging tests may be used to determine any irritation or damage to soft-tissue structures such as tendons or ligaments. Because navicular accessory bone irritation can lead to bunions, heel spurs and plantar fasciitis, it?s important to seek treatment.

Non Surgical Treatment
Ideally, getting rid of the symptoms of accessory navicular syndrome will involve soothing the inflammation and irritation in your foot. So, for starters, your podiatrist may have you rest the area, allowing the inflamed tendon and bone to heal. This may be accomplished by wearing a cast or boot designed to keep you from moving the problem area. Your podiatrist may also suggest using ice to reduce the swelling and inflammation, and anti-inflammatory medications (like ibuprofen, or sometimes a cortisone shot or other steroid medication).



Surgical Treatment
Fusion of the accessory navicular to the navicular with screws is required when there is a large accessory navicular bone and removal of this bone would reduce the articular surface of the Navicular to the talus (coxa pedis). Fusion will relieve pain without disrupting the tibialis posterior tendon insertion nor narrowing talar head support. In most instances, a patient’s recovery will be as follows. 0-6 weeks: Immobilization (in case or cast boot) non-weight-bearing or touch weight-bearing. 6-10 weeks: Increasing activity in a cast boot. Physical therapy to work on strength and balance. Full recovery after 9 weeks-2 months. In some patients (where the posterior tibial tendon is still intact and functioning) the treating surgeon may allow weight-bearing as tolerated in a cast boot immediately after surgery.