An accessory navicular is an extra bone or bit of cartilage material in the arch of the foot that may or may not bring about problems. Also, it is often called an os navicularum or os tibiale externum. It is included within the tendon of the posterior tibial muscle that inserts in the area. The extra bone is on the inside side of the navicular bone that is the bone which is at the top of the mid-foot of the feet. It is present in from 5-15% of the population. It is not usually an issue, but the prominence of the bone may make force from the shoes painful. In some cases the accessory bone is at such a location which it will modify the angle of pull with the posterior tibial muscle which will affect foot function and can bring about any number of biomechanical issues, such as a flat foot.
The diagnosis is generally by a x-ray in which the existence of the bone is obvious. There are various types which the x-ray may help figure out which one it is. The Geist grouping breaks the accessory navicular bones in to three different kinds. Each of the three kinds influences the structure and biomechanics of the foot in a different way and each of the 3 differing types will need a distinct therapy method.
The aim of treatment is to ease the signs and symptoms and stop it being painful. In the event the pain is especially bad, then putting the foot within a fibreglass cast or replaceable walking brace allows the affected region to rest which helps the pain. Ice could also be used to help reduce inflammation. Oral nonsteroidal anti-inflammatory drugs (NSAIDs) can be utilized in combination with immobilization to help lessen the inflammation and pain. Exercises and therapies to strengthen the muscles may also be recommended, especially over the long term that can help prevent a recurrence of the symptoms. Foot orthotic devices are extremely beneficial to defend the foot and become mainly useful in the event the accessory navicular is causing a flat foot.
The accessory navicular bone is often a particular problem is sports such as skiing as well as ice skating. For the reason that the boots of these sports activities goes right around the foot and it is fairly inflexible. And so, if someone has a prominent piece of bone on the feet, such as an accessory navicular, this could be quite painful as well as challenging to handle. Items like doughnut shaped padding to deflect the force coming from the footwear off of the prominence is often very helpful. This can be where the expertise of a boot maker or a competent ski boot fitter will be very helpful. They are used to managing these types of challenges and can customize the boot around the prominent bone so it will be more at ease. A foot doctor can often help with all of this.
If the traditional non-surgical therapies tend not to eliminate the signs and symptoms, after that surgical procedures could be appropriate. Surgical procedures could include removing the accessory bone, re-shaping the area and repairing the posterior tibial tendon to enhance its biomechanics. This additional bone isn't really needed for normal foot biomechanics, and so in theory it won't be a problem.