Accessory Navicular Syndrome
Each foot is made up of 28 bones. In approximately 10% of the population there is an “extra” bone on the inner part of the foot, by the arch. The accessory bone is referred medically as Os Navicularum or Os Tibiale Externum. It is often incorporated within the posterior tibial tendon, which is extensively involved in walking.
This abnormal bone structure is congenital (present at birth), therefore not common in everyone.
Most people are unaware that they have an accessory navicular bone as it does not cause any discomfort. However, in some cases, the extra bone can become irritated and causes a painful condition known as accessory navicular syndrome. This can be result from:
This type of condition can affect people of all ages, although it is most seen in adolescence when the bones are maturing. The most common signs and symptoms are:
Diagnosis:
The foot and ankle specialist will ask about symptoms and exam the foot for any irregular prominences and swelling. Overall, the foot structure, muscle strength, joint motion and integrity of the tendons will be examined.
X-rays are routinely performed to confirm the diagnosis. If there is worsening pain and inflammation, other advanced imaging modalities such as an MRI can be used to further evaluate the condition.
Treatment:
The goal is to relieve the symptoms.
If non-surgical treatment fails to relieve the symptoms, surgery may be recommended.
Each foot is made up of 28 bones. In approximately 10% of the population there is an “extra” bone on the inner part of the foot, by the arch. The accessory bone is referred medically as Os Navicularum or Os Tibiale Externum. It is often incorporated within the posterior tibial tendon, which is extensively involved in walking.
This abnormal bone structure is congenital (present at birth), therefore not common in everyone.
Most people are unaware that they have an accessory navicular bone as it does not cause any discomfort. However, in some cases, the extra bone can become irritated and causes a painful condition known as accessory navicular syndrome. This can be result from:
- Trauma
- Mechanical: improper footwear
- Overuse: increase in activity
- Biomechanical: Flatfoot/fallen arch
This type of condition can affect people of all ages, although it is most seen in adolescence when the bones are maturing. The most common signs and symptoms are:
- Pain and throbbing in the midfoot, worst upon standing for an extended period
- A visible prominence on the inner part of the foot, just above the arch
- Swelling and redness at the bony prominence
Diagnosis:
The foot and ankle specialist will ask about symptoms and exam the foot for any irregular prominences and swelling. Overall, the foot structure, muscle strength, joint motion and integrity of the tendons will be examined.
X-rays are routinely performed to confirm the diagnosis. If there is worsening pain and inflammation, other advanced imaging modalities such as an MRI can be used to further evaluate the condition.
Treatment:
The goal is to relieve the symptoms.
- Immobilization
- Ice
- Medications: nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen. In some cases, oral steroids may be used.
- Physical therapy
- Orthotics/Inserts
- Rest: switching to another activity that isn’t as high impact on the foot
If non-surgical treatment fails to relieve the symptoms, surgery may be recommended.