What is Accessory Navicular Syndrome?

In order to understand Accessory Navicular Syndrome, it is essential to know what accessory navicular means. Accessory Navicular which is also known by the name of os navicularum is the name given to an extra bone or a piece of cartilage which is normally found on the inner side of the foot just above the arch. This extra bone is fixed within the posterior tibial tendon which is attached in this area. Accessory Navicular is a congenital issue which means that the extra bone is present at birth. Accessory Navicular is not a part of the normal bony anatomy and hence is not found in every person.

What is Accessory Navicular Syndrome?

Now coming to what is Accessory Navicular Syndrome, this is a condition in which the Accessory Navicular starts to become painful when aggravated. Accessory Navicular Syndrome may occur due to any of the following causes:

  • Trauma to the foot or ankle such as a sprain
  • Chronic irritation from shoes rubbing against the bone
  • Overuse of the foot like standing and walking for prolonged periods thus irritating the bony structure.

It has also been observed that many individual suffering from Accessory Navicular Syndrome have flat feet. This condition puts more strain on the posterior tibial tendon which attaches to the foot where the Accessory Navicular is and thus irritates the Accessory Navicular and inflames or irritates it causing immense pain due to Accessory Navicular Syndrome.

What are the Causes of Accessory Navicular Syndrome?

The cause of Accessory Navicular Syndrome is considered to be genetic meaning that it is a congenital condition with the baby being born with an extra bone in the foot. Researchers have come to this conclusion after studying numerous families with this condition, they are of the belief that this condition is of an autosomal dominant type which means that if only one parent has the gene that can cause the Accessory Navicular Syndrome then it is quite possible that the offspring will have the condition as well. Another theory regarding Accessory Navicular Syndrome is that it may occur due to incomplete fusion of bones and connective tissues during fetal development causing Accessory Navicular Syndrome.

What are the Symptoms of Accessory Navicular Syndrome?

The symptoms of Accessory Navicular Syndrome first begin when the child reaches puberty or when he becomes an adolescent, as this is the time when the bones start to mature and the cartilages start to convert to bones, although there are cases where the child remains asymptomatic until adulthood. Some of the symptoms of Accessory Navicular Syndrome are:

  • A visible bony prominence on the midfoot
  • Redness and erythema surrounding the bony prominence
  • Vague complaints of pain in the midfoot and arch, especially after activities such as walking or running in which pressure is put on the foot and ankle.

How is Accessory Navicular Syndrome Diagnosed?

A visual inspection of the area in question that is the foot area near the arch will clearly show a protruding bone which will clearly point towards an Accessory Navicular; however, the doctor to confirm the diagnosis of Accessory Navicular Syndrome will inquire from the patient about whether he or she is experiencing any symptoms of pain in the foot with or without activity. The doctor will also palpate the area to look for any areas of tenderness or pain. In order to confirm the diagnosis of Accessory Navicular Syndrome, the doctor may order radiological studies in the form of x-rays, MRI or CT scan of the foot in question. These studies will clearly show the presence of Accessory Navicular thus confirming the diagnosis of Accessory Navicular Syndrome.

How is Accessory Navicular Syndrome Treated?

The treatment for Accessory Navicular Syndrome is two fold, surgical and nonsurgical approaches. The nonsurgical approaches are aimed at relieving the symptoms caused due to Accessory Navicular Syndrome and help the patient lead as normal life as possible. The following are the nonsurgical approaches to treat Accessory Navicular Syndrome:

Immobilization: This is quite an effective way to calm down the symptoms of Accessory Navicular Syndrome. For this, the affected foot may be put in a cast or a walking boot to decrease the area of inflammation and allow the foot to rest by immobilizing it.

Ice: This is also quite an effective way to calm down the inflammation and other symptoms of Accessory Navicular Syndrome. The patient should ice the affected foot for 15-20 minutes two to three times a day. It should be noted here that ice should never be applied directly to the skin but should be wrapped in towel or a cloth and then put to prevent development of blisters.

Medications to Treat Accessory Navicular Syndrome: The doctor may also prescribe NSAIDs in the form of Tylenol or ibuprofen to calm down the swelling, pain, and inflammation due to Accessory Navicular Syndrome. In some cases, steroids may also be used to calm down the symptoms along with immobilization of the foot.

Physical Therapy for Accessory Navicular Syndrome: This is an essential part of treatment for Accessory Navicular Syndrome, especially when the foot has been immobilized for some weeks as immobilization may make the foot stiff and there may be a loss of range of motion. In such cases, physical therapy is useful in regaining the strength and range of motion back. It also helps in decreasing the inflammation.

Orthotics: The use of orthotics has also been shown to be quite effective in treatment of Accessory Navicular Syndrome. These devices support the arch and help in preventing symptoms of Accessory Navicular Syndrome to occur.

Surgical Treatment for Accessory Navicular Syndrome: If all of the above methods fail to relieve the patient's symptoms of Accessory Navicular Syndrome, then surgical approach is recommended. The surgical treatment for accessory navicular syndrome involves complete removal of the extra bone that is present in the foot in hopes of relieving the patient's symptoms. The surgery will involve removing the extra bone, reconstructing or reshaping the area, and repair the posterior tibial tendon so that it starts to function normally thus relieving the symptoms that the patient experiences due to Accessory Navicular Syndrome.

Written, Edited or Reviewed By:


Last Modified On: October 14, 2016

Pain Assist Inc.

Pramod Kerkar
  Note: Information provided is not a substitute for physician, hospital or any form of medical care. Examination and Investigation is necessary for correct diagnosis.

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