Accessory Navicular Bone Syndrome
Some patients are born with an extra bone, known as an accessory navicular bone, located on the inside of the foot just above the arch. In many cases, this extra bone causes no problem and requires no treatment, but in some patients it may enlarge, causing pain, particularly during or after walking or athletic activity. Patients affected in this way are said to have accessory navicular bone syndrome. They present with a red, swollen protrusion in the middle of the foot that may cause them to limp. Patients with accessory navicular bone syndrome may also develop plantar fasciitis, bunions or heel spurs. Most often, accessory navicular bone syndrome can be treated nonsurgically, but occasionally surgical intervention is necessary.
Reasons for Accessory Navicular Bone Syndrome
Accessory navicular bone syndrome typically develops when the abnormal bone, or the posterior tibial tendon to which it attaches, are irritated. This may be the result of:
- Traumatic injury to the foot or ankle
- Constant rubbing of footwear against the bone
- Excessive exercise or overuse
Many patients with accessory navicular syndrome also have flat feet which, because a flat foot puts more stress on the posterior tibial tendon, exacerbates the condition.
Nonsurgical Treatment of Accessory Navicular Bone Syndrome
There are several treatment options for accessory navicular bone syndrome. These may include some or all of the following:
- Immobilization with a cast or walking boot
- Applications of ice packs
- Non-steroidal anti-inflammatory drugs (NSAIDs)
- Injected steroids
- Physical therapy
They first four methods listed are designed to reduce swelling and alleviate pain. The goal of the remaining two is to strengthen muscle, reposition the foot correctly, and prevent recurrence of injury.
Surgical Treatment of Accessory Navicular Bone Syndrome
The Kidner procedure is the most common surgical treatment for accessory navicular bone syndrome. This procedure involves detaching the bone from the posterior tibial tendon and then removing it entirely from the foot. The tibial tendon is then reattached and the incision is closed with stitches. Patients will likely wear a light cast and use crutches after surgery. They will require some physical rehabilitation focused on stretching the affected tendon and should be able to resume normal physical activity after about 6 weeks.
- National Institutes of Health
- Centers for Disease Control and Prevention
- Eunice Kennedy Shriver National Institute of Child Health and Human Development
- U.S. Department of Health & Human Services
- U.S. National library of Medicine
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