Accessory navicular bone / Os tibiale externum
Accessory navicular bone is the presence of an extra bone growth core on the inner side of the navicular bone of the foot where the tibialis posterior tendon is attached.
The main common symptom of patients with this condition is swelling, pain and tenderness, often combined with a flatfoot deformity. Very often pain starts after lng walking periods or impact sports activities like running, jumping and competitive ball games with frequent changes of running direction.
This condition belongs to the congenital conditions as it is present from birth even that it can not be seen in early x-rays due to the cartilaginous nature of immature bones.
The treatment is usually conservative with orthotics and treatment of additional deformities. In case of chronic pain an individual small surgical treatment with removal of the accessory bone can be done, related to the individual findings, with short rehabilitation and very good success rate.