Foot Pain Accessory Navicular Bone

Overview
In an ideal situation, the navicular bone and the accessory bone will fuse together to form one bone. The problem that occurs is that sometimes the two bones do not fuse together and the patient is left with what is known as a fibrous union or basically a non solid union of bone to bone. This fibrous union is more like scar tissue and in theory can cause pain when excessive strain is placed upon it.



Causes
An injury to the fibrous tissue connecting the two bones can cause something similar to a fracture. The injury allows movement to occur between the navicular and the accessory bone and is thought to be the cause of pain. The fibrous tissue is prone to poor healing and may continue to cause pain. Because the posterior tibial tendon attaches to the accessory navicular, it constantly pulls on the bone, creating even more motion between the fragments with each step.

Symptoms
This painful condition is called accessory navicular syndrome. Accessory navicular syndrome (ANS) can cause significant pain in the mid-foot and arch, especially with activity. Redness and swelling may develop over this bony prominence, as well as extreme sensitivity to pressure. Sometimes people may be unable to wear shoes because the area is too sensitive.

Diagnosis
To diagnose accessory navicular syndrome, medical staff ask about the patient?s activities and symptoms. They will examine the foot for irritation or swelling. Medical staff evaluate the bone structure, muscle, joint motion, and the patient?s gait. X-rays can usually confirm the diagnosis. MRI or other imaging tests may be used to determine any irritation or damage to soft-tissue structures such as tendons or ligaments. Because navicular accessory bone irritation can lead to bunions, heel spurs and plantar fasciitis, it?s important to seek treatment.

Non Surgical Treatment
The treatment for a symptomatic accessory navicular can be divided into nonsurgical treatment and surgical treatment. In the vast majority of cases, treatment usually begins with nonsurgical measures such as orthotics, strappings or bracing. Surgery usually is only considered when all nonsurgical measures have failed to control your problem and the pain becomes intolerable.



Surgical Treatment
In the original Kidner procedure, the entire posterior tibial tendon was released from the navicular and then rerouted through a drill hole placed through the navicular. The original Kidner procedure is now rarely used as a means of treating an isolated accessory navicular. Instead, a modification of the Kidner procedure has become more commonplace. The modified Kidner procedure consists of carefully removing the accessory and anchoring the posterior tibial tendon to the surface of the navicular where the accessory was removed. The repair may be done by passing a suture through the tendon and then through drill holes in the navicular, or by using a suture anchor.