Most of us have two bones, called sesamoid bones, under the joint at the base of the big toes. In rare instances, people may be missing one or both of these bones.1 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,2 or a condition called osteonecrosis. Less common causes of sesamoiditis include infection or systemic disorders such as autoimmune diseases. People with chronic sesamoid pain should be evaluated for these conditions.
Sesamoid problems are usually detectable by a careful history and examination. The most common symptoms1 include:
Pain with weight-bearing
Pain with pressure applied directly to the sesamoid bones
Pain when the great toe is forcefully pulled upwards (dorsiflexion of the great toe)
Other conditions that can cause similar symptoms include hallux rigidus and gout.3
Diagnosis can be confirmed with imaging tests. X-rays can be helpful, especially if a fracture of the sesamoid bone is suspected. However, sometimes the small sesamoid bones are difficult to adequately visualize on an x-ray test, and therefore other tests may also be considered. The most commonly used test is an MRI study, but bone scans can also be effective to identify sesamoid problems.1
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.1
Recovery from a sesamoid injury can take months and is often a frustrating experience. Athletes may require a prolonged period of restricted weight-bearing or mobility, and often recovery to full sports activities can take 3 to 6 months.
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 cautiously1, as deformities of the big toe can often result if one or both of the sesamoid bones are removed.