What Is the Accessory Navicular?
The accessory navicular is an extra bone or piece of cartilage located on the inner side of the foot, just above the arch. It’s adjacent to the navicular bone, one of the bones in the midfoot that helps form the arch and connect tendons.
This extra bone is considered a congenital condition, meaning you are born with it. While many people with an accessory navicular experience no symptoms, others may develop pain and inflammation, particularly during adolescence or after injury or overuse.
What Causes an Accessory Navicular to Form?
An accessory navicular forms during bone development, typically in childhood. Instead of fusing completely with the navicular bone, a separate ossicle remains.
Factors that can cause symptoms to arise later include:
- Trauma or injury to the foot
- Overuse from physical activity
- Tight or poorly fitting shoes placing pressure on the area
- Flat feet, which place more stress on the posterior tibial tendon attached to the navicular bone
- Growth spurts during adolescence
Symptoms of Accessory Navicular Problems
Most individuals with this condition are asymptomatic, but for those who do have symptoms, common signs include:
- Pain or throbbing on the inner side of the foot
- Swelling or redness over the bony bump
- Pain that worsens with physical activity or tight footwear
- Difficulty wearing certain shoes
- In some cases, tendon irritation or dysfunction in the posterior tibial tendon, which supports the arch
How Accessory Navicular is Treated
Treatment depends on the severity of symptoms. In most cases, conservative care is effective.
Non-Surgical Treatment:
- Rest and ice to reduce inflammation
- NSAIDs (non-steroidal anti-inflammatory drugs) for pain relief
- Immobilization with a walking boot or cast to offload pressure
- Orthotics or arch supports to reduce strain on the posterior tibial tendon
- Physical therapy to strengthen the foot and improve biomechanics
Surgical Treatment:
If conservative measures fail and pain persists, surgical removal of the accessory navicular may be recommended. This procedure is called a Kidner procedure and may include tendon repositioning.
FAQs
For many, it’s not serious and doesn’t cause problems. However, when symptomatic, it can significantly impact daily activity, exercise, and footwear comfort.
Surgery is usually reserved for cases where conservative treatment fails. For those with persistent pain and limited function, surgery can provide long-term relief and restore mobility.
An accessory navicular is found in about 10–15% of the population. However, not everyone with the extra bone experiences symptoms.
Removal may be considered if you’ve tried non-surgical treatments without relief, the bone causes chronic pain or functional limitations, or the bump causes frequent irritation from shoes. Discuss the risks and benefits with your orthopedic specialist.
Yes. Accessory navicular bones are usually visible on standard foot X-rays, especially from a lateral or oblique view. An MRI may be used to assess associated tendon inflammation.
With non-surgical treatment, symptoms typically improve over 6–8 weeks, though recovery can take longer with tendon involvement. Post-surgical recovery may take 8–12 weeks or more, including physical therapy.
Pain is usually felt on the inner side of the foot, just above the arch. It may worsen with activity, pressure, or tight footwear.
