There are two little bones underneath the big toe which are embedded in a tendon that flexes the toe. These bones are exposed to a lot of pressure and at times they can become arthritic or not have sufficient blood supply which is called avascular necrosis (AVN) of the bone. Sometimes there are only signs of an inflammation in the little bones, other times the bones present as not completely calcified (bipartite sesamoid) and only one part of the bones is inflamed. All of these pathologies can cause pain underneath the big toe and imaging, especially an MRI scan will help to confirm the correct diagnosis.
The aim of the treatment is to reduce the pressure on the area under the big toe where the sesamoids are located. Footwear modification and insoles can be really helpful but stretching of a tight calf muscle and physiotherapy will provide further relief. Relative rest and avoiding stress to the forefoot will also be necessary to reduce the overload. In case of inflammation in the joint, a cortisone injection will reduce the pain. In case of ongoing pain, an operation might be necessary which means one has to remove part or the whole sesamoid which is responsible for the pain. As the tendon is left intact the function of the toe is preserved and patients will soon be aware of the benefit of having the damaged sesamoid removed.