Updated July 23, 2015.

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Everyone has two bones, called sesamoid bones, under the joint at the base of the big toes. These sesamoid bones are actually enveloped within the tendons under the big toe. When these bones become inflamed, the condition is called sesamoiditis.
Sesamoiditis can be caused by acute injury or chronic overuse. Sesamoid pain can also be caused by stress fractures of the sesamoid, or a condition called osteonecrosis.

People with chronic sesamoid pain should be evaluated for these conditions.

Treatment of Sesamoiditis

The treatment of sesamoiditis begins with altering footwear. Increasing the amount of cushioning within your shoes can help relieve pressure on the affected sesamoid. Specific inserts or custom orthotics can also be used to try to shift forces away from the inflamed bone. Other treatments include resting, avoiding specific activities that irritate the bone, non-steroidal anti-inflammatory medications, and ice application.
In the unusual circumstance that footwear modifications and rest are insufficient to relieve the discomfort, there are surgical treatment options. However, these surgical procedures should be approached cautiously, as deformities of the big toe can often result if one or both of the sesamoid bones are removed.

<sub>Sources:

Richardson EG. "Hallucal sesamoid pain: causes and surgical treatment" J. Am. Acad. Ortho. Surg., Jul 1999; 7: 270 - 278.</sub>