The accessory navicular is an additional section of cartilage or bone on the interior flank of the foot right over the arch. It is incorporated inside the posterior tibial tendon which links in this area.
An accessory navicular is usually present at birth. Remember that it is not a component of the normal bone structure and not present in most individuals.
An individual with an accessory navicular is often unaware of having one if it does not trigger any issues. Nevertheless, some who have the extra bone experience a painful condition called as accessory navicular syndrome if the bone and/or posterior tibial tendon is irritated. It can result from any of the following:
- Trauma such as an ankle or foot sprain
- Excessive activity or overuse
- Chronic irritation from certain shoes or other footwear that rubs against the extra bone
Many individuals with accessory navicular syndrome also have flatfeet. Take note that having flatfeet places more strain on the posterior tibial tendon which triggers increased irritation or inflammation of the accessory navicular.
What are the indications?
The teenage years is the usual time for the symptoms to arise. This is the period where the bones are starting to mature and cartilage is developing into bone. Oftentimes, the symptoms do not arise until adulthood.
The usual indications of accessory navicular syndrome include:
- Evident bony protrusion on the midfoot
- Swelling and redness of the bony protuberance
- Vague discomfort or throbbing sensation in the midfoot as well as the arch, typically throughout or after periods of movement
The objective of conservative treatment for accessory navicular syndrome is to alleviate the symptoms such as:
- Application of ice to reduce the swelling
- Immobilization by placing the affected foot in a cast or detachable walking boot to allow the area to rest and reduce the inflammation
- Oral medications such as non-steroidal anti-inflammatory drugs (NSAIDs) can be given. In some cases, oral or injectable steroid medications might be used along with immobilization to allow the pain and inflammation to settle.
- Orthotic devices are fitted into the shoes for added support to the arch and even help in the prevention of future symptoms
- Physical therapy includes exercises and treatment modalities to strengthen the muscles and reduce the inflammation
Take note that even after successful treatment, the symptoms might oftentimes recur. Once this occurs, the conservative measures are repeated.