Sesamoiditis: What you need to know

Sesamoid bones are unique to other bones of the body in that they are not connected to other bones via joints. Instead they are connected by tendons or embedded into muscle tissue.

The kneecap and two small bones in the foot are examples of sesamoid bones. They are about the size of a corn kernel. The sesamoid bones of the feet are embedded into the tendons that cause the big toe to move. 

What is sesamoiditis?

The sesamoid bones support your body’s weight. This allows tendons to deliver greater forces on the body, and aid in the lifting of the big toe. 

Sesamoiditis is the inflammation and irritation of these small bones. Ballet dancers, baseball catchers, and runners develop this condition due to the high demand placed on the feet during these activities. Those with a high arch in their feet are also at higher risk of experiencing ball of foot pain due to extra pressure placed on the feet. Adults with osteoarthritis can also experience pain under the big toe due to weakened bones leading to increased inflammation. 

Symptoms of Sesamoiditis

Sesamoid bone fractures can occur with or without sesamoiditis. This makes it challenging at times to decipher between the two conditions. Pain will occur almost immediately following a fracture of a sesamoid bone, but individuals with sesamoiditis will experience pain gradually. 

Other symptoms of sesamoiditis are the following:

• Bruising 
• Difficulty bending or straightening the big toe
• Swelling
• Pain on the bottom of the foot

Sesamoiditis develops over time. Most patients describe it as a dull pain that comes and goes throughout the day. Pain is usually experienced on the bottom of the foot and toes. The pain caused by sesamoiditis can negatively influence the way a person walks. They may have to shift their weight to the other foot. This reduces the amount of pressure on the bad side.