Question 1

What is an accessory navicular?

Accepted Answer

An accessory navicular is an extra piece of bone or cartilage on the inner side of your foot, located just above the arch where the navicular bone is. You're born with it - it forms during foot development when a small piece of bone doesn't fuse to the main navicular bone as it normally should. About 10-15% of people have an accessory navicular, but most never have symptoms. It only becomes a problem (called accessory navicular syndrome) when it causes pain, usually because the posterior tibial tendon attaches to this unstable extra bone instead of the stable main navicular. This can happen after injury, or when you start intensive athletic activities during adolescence.

Question 2

Why does it suddenly start hurting if I've always had it?

Accepted Answer

Many people have an accessory navicular their whole lives without problems until something triggers symptoms. Common triggers include: starting a new sport or increasing training intensity (stress on the tendon attachment), a direct blow or sprain to the inside of the foot, wearing shoes that press on the bony prominence, growth spurts in adolescence, or gradual stretching and weakening of the posterior tibial tendon over time. The extra bone is inherently unstable because it's only connected by cartilage or weak fibrous tissue, not solid bone. Increased stress on your foot can cause this connection to become inflamed and painful.

Question 3

Will my foot become more flat over time?

Accepted Answer

Possibly, but not always. The posterior tibial tendon is the main support for your foot's arch. When it attaches to an unstable accessory navicular instead of solid bone, it can't work as efficiently. Over time, the tendon may stretch and weaken, causing your arch to gradually flatten. This is more likely if you continue high-impact activities without proper treatment or support. However, with good management (orthotics, strengthening exercises, appropriate footwear), many people maintain their arch height. If you have surgery (Kidner procedure), the tendon is reattached more securely, which can actually improve arch support.

Question 4

Can orthotics really help or do I need surgery?

Accepted Answer

Orthotics help about 60-70% of people avoid surgery. They work by supporting your arch and taking stress off the accessory navicular and tendon attachment. Custom orthotics are more effective than over-the-counter inserts for this condition. The key is consistent use - wear them in all your shoes, including at home. Combined with proper footwear, activity modification, and strengthening exercises, many people become pain-free with orthotics alone. Surgery is reserved for people who have tried non-surgical treatment for at least 4-6 months without adequate relief. Don't rush to surgery - give conservative treatment a proper trial first.

Question 5

What happens during the Kidner procedure?

Accepted Answer

The Kidner procedure removes the painful accessory bone and reattaches the posterior tibial tendon more securely. Through a 5-7cm incision on the inner side of your foot, the surgeon exposes the accessory navicular, detaches the posterior tibial tendon from it, removes the extra bone, smooths down any remaining bony prominence on the main navicular, and drills a hole or creates a groove to reattach the tendon more securely to solid bone. This gives the tendon a stable attachment point. Some surgeons also tighten the tendon or reinforce it. The incision is closed with stitches. The procedure has been performed for over 70 years and has well-established good results.

Medical Disclaimer

Accessory Navicular (Extra Bone in Foot)

📖What is Accessory Navicular (Extra Bone in Foot)?

🔬What Causes It?

⚠️Risk Factors

You may be at higher risk if:

🛡️Prevention