Physical Therapy Exercises For Accessory Navicular Syndrome

Overview
An accessory navicular bone is an accessory bone of the foot that occasionally develops abnormally in front of the ankle towards the inside of the foot. This bone may be present in approximately 2-14% of the general population and is usually asymptomatic. When it is symptomatic, surgery may be necessary. Surgery can be performed at any age because it does not alter any other bones.



Causes
Just having an accessory navicular bone is not necessarily a bad thing. Not all people with these accessory bones have symptoms. Symptoms arise when the accessory navicular is overly large or when an injury disrupts the fibrous tissue between the navicular and the accessory navicular. A very large accessory navicular can cause a bump on the instep that rubs on your shoe causing pain.

Symptoms
Many people have accessory (?extra?) naviculars (figure 1) - a prominent extra bone extending from the navicular bone. Most accessory naviculars are completely asymptomatic. However, some individuals will develop pain on the inside of their midfoot. Pain may occur from the pressure of the shoe ware against the prominence, irritating either the bone itself or the fibrous junction where the accessory bone meets the regular navicular. Alternatively, the fibrous junction or interface may become painful as a result of tension applied by the posterior tibial tendon through its connection or insertion at that site. Often, individuals will be asymptomatic for years, however, a new pair of shoes or a change in their activity level can cause symptoms. The accessory navicular itself typically develops during adolescence, when the two areas of the navicular bone fail to fuse together.

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
The foot may be placed in a cast or removable walking boot to allow the affected area to rest and decrease the inflammation. Physical therapy including exercises and treatments to strengthen the muscles, decrease inflammation, and prevent recurrence of the symptoms. Custom orthopedic devices that fit into the shoe providing arch support. Even after successful treatment, symptoms may reappear.



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.