Wednesday, November 30, 2022
Common Foot Problems FOOT HEALTH

Painful Navicular Accessory Foot Bone- How Do You Treat It?

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The accessory navicular is a small bone located in the inner arch of the foot. Many people with an accessory navicular bone do not experience pain. However, some people may experience discomfort due to the bone rubbing against shoe gear or the area being strained during physical activity.

Treatment for an accessory navicular typically focuses on relieving symptoms and may include rest, ice, and stretching exercises. In severe cases, surgery may be necessary to remove the bone.

In this article, we’ll discuss in detail what you can do if you have a painful accessory navicular bone. 

Let’s dive in…

anatomy inner foot

Anatomy

The navicular bone is a bone that is located on the inner portion of the midfoot. The inner prominence of the navicular is known as the “navicular tuberosity”. 

The tibialis posterior tendon is the tendon that is responsible for holding up the arch of the foot and aids with supination. The tibialis posterior tendon inserts at the navicular bone. 

Most bones in the foot start as cartilage and begin to harden at different stages. The navicular bone fully forms at ages 2 ½ to 5 years of age. In some people, the navicular bone doesn’t fully fuse, and thus an accessory bone may be present. 

runner with foot pain

What Causes an Accessory Navicular Bone to Become Painful?

An accessory navicular bone can become painful from inappropriate shoe gear rubbing on the bone, sporting injuries that cause direct damage to the bone (such as a sprain), and chronic posterior tibial tendonitis that can pull on the accessory navicular bone thus causing stress and strain.

There Are Three Types of Accessory Navicular Bones:

Type 1

This accessory navicular bone presents as a small 4mm-6mm ossicle that is present in the posterior tibial tendon itself. It rarely is symptomatic, unless the posterior tibial tendon is inflamed/irritated. It is known as the “Os tibialis externum”. 

Type 2 

This accessory navicular bone presents as a separate ossicle that appears to be an extension of the navicular bone. It is a heart-shaped or triangular-shaped piece of bone that is located on the inner side of the navicular. The accessory bone is connected to the navicular by cartilage, fibrous tissue, or bone. It is known as the “bifurcate navicular”. 

Type 3

This accessory navicular bone presents as an extension of the navicular tuberosity. A prominent bump can be seen on the inside of the foot. This is called a “cornuate navicular”. 

How Many People Have an Accessory Navicular Bone?

The accessory navicular bone is one of the most common accessory bones in the foot, occurring in 4-21% of people (1). Most people do not feel pain from the accessory navicular bone.

man having foot pain

Symptoms of a Painful Accessory Navicular Bone in the Foot

  • Achiness on the inside of the midfoot
  • Midfoot swelling
  • Bruising of the midfoot
  • Inability to stand up on your tip-toes due to pain
  • Pain when bearing weight on the foot that is relieved with rest
  • A prominent bump near the inner arch area of the foot

How Is the Painful Accessory Navicular Bone Diagnosed?

If you have dull achy pain on the inner midfoot, you should visit your local foot doctor to be evaluated. Your doctor will determine the area of pain by pressing on the navicular bone as well as the posterior tibial tendon that inserts into the navicular bone.

When you have a painful accessory navicular bone, even light touch over the area can cause pain.

Your doctor will assess your foot structure. Oftentimes, flatfooted individuals (due to strain on their arch from their foot structure) experience pain in the accessory navicular bone and posterior tibial tendon. 

Your doctor will also check the strength of the posterior tibial tendon by having you step on your tiptoes. If you are unable to step up on your tiptoes, this suggests weakness of the posterior tibial tendon. 

Your doctor will order an x-ray to confirm the presence of an accessory navicular bone.

Your doctor may choose to order an MRI to visualize the area in more detail. The MRI would show altered signal intensity and bone marrow edema, indicating chronic stress to the navicular bone (2). Since an MRI shows detailed images of the bones, ligaments, and tendons of the foot, it can also help identify the presence of a posterior tibial tendon tear/rupture. This can be incredibly helpful when it comes to surgical planning.

Your doctor may choose to order a CT scan to visualize the bone cortex (outer layer of bone), as well as the joint that articulates with the navicular (talonavicular joint). A CT scan can also be helpful in identifying stress fractures if they are present.

A bone scan can also help identify an accessory navicular bone, as it would show increased uptake in the area of pain. 

pills

How Do You Treat an Accessory Navicular Bone?

Non-surgical Treatment for the Accessory Navicular Bone

If possible, the accessory navicular bone should be treated conservatively.

Treatment for accessory navicular bone includes RICE therapy, NSAIDs, and orthotics. 

Since the posterior tibial tendon that is responsible for holding up the arch is also inflamed (in most cases), arch supports can be greatly beneficial in alleviating pain associated with the accessory navicular bone.

I recommend Powerstep orthotics to help with this. The Powerstep insoles have a firm arch that helps hold the arch up, a deep heel cup that keeps the heels from sliding when you stand and walk, and can fit into multiple shoes. One pair of orthotics will last 6 months to 1 year. 

  • For mild to moderate flat feet: I would recommend the Powerstep Protech orthotics. These are the standard Powerstep inserts that work well for elevating the arch of the foot.
  • For severe flat feet: I would recommend the Powerstep Maxx orthotics. These orthotics have the same features as the Powerstep Protech orthotic, however, it has an added extrinsic heel lift on the bottom of the orthotic to help with overpronation.
  • For high-arched feet: I would recommend the Powerstep Pinnacle High Arch orthotics. These inserts contour high-arched feet well and are supportive. 

If this doesn’t work, you may need custom orthotics. If this is the case, visit your local foot doctor to have a mold of your feet taken so you can get a pair of custom orthotics.

Custom orthotics can be pricey and range anywhere from $300 to $600, however they last much longer than over-the-counter inserts. Also, the modifications that can be made in custom orthotics are greatly beneficial. 

For instance, a medial flange can be added to the arch of the orthotics to alleviate pressure along the inside of the foot and cushion the navicular bone. Custom orthotics generally last 5-10 years. 

Surgery for the Accessory Navicular Bone

Is It Necessary to Remove the Accessory Navicular Bone?

If conservative treatment fails, your doctor may suggest surgery. This would be done under anesthesia. Your doctor will remove the accessory navicular bone.

If there is evidence of posterior tibial tendon disease, your doctor will remove the devitalized portion of the tendon. The tendon will then be reinserted into its proper position on the bottom of the navicular bone using strong anchors. This is known as a Kidner procedure. 

After the Kidner procedure, you will need to stay immobilized in a cast boot/splint for 6-8 weeks. After which you may walk in the cast boot for 2-4 followed by gradual transitioning to weight bearing in athletic shoes. 

Physical therapy may be needed after the surgery to regain strength and improve mobility. 

Occasionally, if you have a painful accessory navicular bone and arthritis in the talonavicular joint, your doctor may fuse the talonavicular joint using screws. This can help alleviate pain.

After the surgery, you will need to stay immobilized in a cast boot/splint for 8 weeks, followed by 4 weeks of gradual weight bearing in a cast boot and then athletic shoes. Recovery can take 3 months. 

walking

When Can I Walk After Accessory Navicular Surgery?

If all goes well after surgery, you should be able to bear weight and walk 6-8 weeks after surgery for a painful accessory navicular bone. Your doctor will evaluate how your foot is doing regularly after surgery. 

Conclusion

In conclusion, if you have pain and swelling on the inside of the midfoot, it should never be ignored. Whether the pain is acute or chronic, you may have an accessory navicular bone that has become painful and needs attention. Make sure you visit your local foot doctor to help you treat this appropriately. 

Related articles: Navicular Foot Fractures- A Helpful Guide

Do you have a painful accessory navicular bone? What helped you treat it? I’d love to hear your thoughts! Leave a comment below. 

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References

  1. Keles Coskun N, Arican RY, Utuk A, Ozcanli H, Sindel T. The incidence of accessory navicular bone types in Turkish subjects. Surg Radiol Anat. 2009 Nov;31(9):675-9.https://pubmed.ncbi.nlm.nih.gov/19367354/#:~:text=The%20aim%20of%20this%20study,subjects%20in%20the%20radiological%20examination
  2. Choi YS, Lee KT, Kang HS, Kim EK. MR imaging findings of painful type II accessory navicular bone: correlation with surgical and pathologic studies. Korean J Radiol. 2004 Oct-Dec;5(4):274-9.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2698172/
  3. Smith TR. Management of dancers with symptomatic accessory navicular: 2 case reports. J Orthop Sports Phys Ther. 2012 May;42(5):465-73. https://pubmed.ncbi.nlm.nih.gov/22281880/
  4. Sahibzada N. Mansoor, Farooq A. Rathore,Symptomatic accessory navicular bone: A case series, The Egyptian Rheumatologist, Volume 39, Issue 4, 2017, Pages 263-266, https://www.sciencedirect.com/science/article/pii/S1110116417300248
  5. Cheong, I., Kang, H., Ko, H., Sung, J., Song, Y., & Hwang, J. (2017). Genetic Influence on Accessory Navicular Bone in the Foot: A Korean Twin and Family Study. Twin Research and Human Genetics, 20(3), 236-241. https://www.cambridge.org/core/journals/twin-research-and-human-genetics/article/genetic-influence-on-accessory-navicular-bone-in-the-foot-a-korean-twin-and-family-study/46E640E6A73957E41EB565CF95F245C5
  6. Macnicol, M. F., & Voutsinas, S. (1984). Surgical treatment of the symptomatic accessory navicular. The Journal of Bone and Joint Surgery. British volume66(2), 218-226.https://online.boneandjoint.org.uk/doi/abs/10.1302/0301-620X.66B2.6707058
  7. Bernaerts, A., Vanhoenacker, F. M., Van de Perre, S., De Schepper, A. M., & Parizel, P. M. (2004). Accessory navicular bone: not such a normal variant. JBR BTR87(5), 250-251.https://www.researchgate.net/profile/Paul-Parizel/publication/8139595_Accessory_navicular_bone_Not_such_a_normal_variant/links/0fcfd5140df0bac2dc000000/Accessory-navicular-bone-Not-such-a-normal-variant.pdf
  8. Kiter, E., Erdag, N., Karatosun, V., & Gunal, I. (1999). Tibialis posterior tendon abnormalities in feet with accessory navicular bone and flatfoot. Acta Orthopaedica Scandinavica70(6), 618-621.https://www.tandfonline.com/doi/abs/10.3109/17453679908997852

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The information, including but not limited to, text, graphics, images and other material contained on this website are for informational purposes only. No material on this site is intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this website.

Vaishnavi Bawa
Dr. Vaishnavi Bawa is a Podiatrist who specializes in treating foot and ankle pathology. LifesLittleSteps mission is to educate the public about foot health in an easy-to-understand manner using evidence-based medicine.
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