Os Navicularis (Accessory Navicular)
Os Navicularis, Accessory Navicular
An accessory navicular bone may be present in individuals young and old. Athletes may find this condition to be painful over the inner aspect of the arch of the foot. The pain can occur in an acute setting from a traumatic injury that disrupts the connection between the accessory navicular and the adjacent bone. On the other hand, the pain can be chronic from overuse and become irritated over time. An accessory navicular can be confused with posterior tibialis tendonitis, which is discussed in another blog post. Individuals may report pain with physical activity, especially activity that involves going up on the toes. Additionally, some people may have pain or irritation to this area with pressure or rubbing from their shoe.
Some athletes will note that there is a large prominence over the inner arch of the foot. They may have tenderness with pressure over this area and can have swelling as well. Individuals may also have pain when asked to stand on their tippy toes or with pushing the foot inwards against resistance. Additionally, some people may have pain or irritation to this area with pressure or rubbing from their shoe. Keep in mind, it is possible that an accessory navicular bone is non-painful and found incidentally on an x-ray of the foot, as shown below.
Os Navicularis X-Ray
In general, pain associated with an accessory navicular will improve over time with an initial period of rest. When the injury occurs in a more acute setting through trauma, a walking boot may help take pressure off the area and allow the inflammation to settle down over a period of 3 to 4 weeks. When the pain occurs due to overuse, relative rest and icing is a good first step. Physical therapy of the foot and ankle can be helpful to prevent return of pain once it is under control. If the pain is more associated with rubbing inside the shoe, a soft foam cushion can be applied, or the athlete can use a wider shoe. In rare cases, the individual may require removal of the accessory navicular bone if conservative measures do not improve symptoms.
Return to Play
Mild irritation from an accessory navicular does not require restriction from activities, and the athlete can usually participate on an as tolerated basis. Moderate pain may require restriction from activities for several weeks to a month, until the pain is better under control and strength in the foot and ankle can be improved. Upon return, the use of a rigid arch support may help.
Athletes whose sport require them to participate bare-footed, such as gymnastics or martial arts, may be more at risk and should consider using rigid arch supports. Also, an athlete should consider cross training and conditioning in a sport that causes less impact, such as swimming or biking.