The human body is rarely the same from person to person. Some things stay the same, like the function of the internal organs. Even when structures are similar, however, little variations, like extra bone tissue, can make a significant difference in the body. Having small, extra bones is not as uncommon as you might think. Sometimes, though, these additional tissues can cause painful problems, as with accessory navicular syndrome.Causes
Like all painful conditions, ANS has a root cause. The cause could be the accessory navicular bone itself producing irritation from shoes or too much activity. Often, however, it is related to injury of one of the structures that attach to the navicular bone. Structures that attach to the navicular bone include abductor hallucis muscle, plantar calcaneonavicular ligament (spring ligament) parts of the deltoid ligament, posterior tibial tendon.Symptoms
Symptoms of this syndrome would include redness, swelling and tenderness over the navicular bone. The navicular bone Where is the Achilles heel
? located on the inside of the foot approximately midway between the ankle bone and big toe joint. It will tend to be worse after activity and can be aggravated by those that wear very dressy shoes as opposed to casual shoes like sneakers. In other words, the flatter or less supportive the shoe, the greater the chance for pain.Diagnosis
Usually, you will only need an X-ray to determine the size or type of the accessory navicular bone or the amount of medial navicular tuberosity hypertrophy. Be cognizant of stress fractures which may be duplicated as a hairline fracture or increased calcification. When treating children, always look for avascular necrosis of the navicular (Kohler?s disease). An X-ray of this condition will reveal a flattening of the navicular along with increased bone density.Non Surgical Treatment
Fortunately, surgery is not the only answer when it comes to relieving symptoms of accessory navicular syndrome. The physician may recommend wearing a cast or walking boot for a period of time so the foot can recover from the inflammation. Ice may be used to relieve swelling, too, although it should be wrapped to avoid direct contact with the skin.Surgical Treatment
The original procedure advocated by Kidner involved shelling out of the accessory navicular bone from within the insertional area of the posterior tibial tendon and rerouting this tendon under the navicular bone in hopes of restoring a normal pull of this tendon. When treating younger children, history has shown us that simply shelling out of the accessory navicular bone from within the tendon and remodeling the tuberosity of the navicular bone can give you satisfactory results.
In general, you want to reserve advancement of the posterior tibial tendon for adults or those who have a more significant flatfoot deformity. You may also use this approach after determining that quality custom orthotics are only resulting in a slight decrease of symptoms.