Sesamoid Injury

A sesamoid bone is a bone embedded within a tendon where the tendon passes over a joint. Tendons themselves are strong bands of tissue that attach the muscles to the bone.

Each foot contains two small sesamoid bones. They are about the size of a pea and are located in the ball of the foot just beneath the big toe joint. A sesamoid acts as a pulley to help a tendon flex and curl. A sesamoid injury affects the bone’s ability to provide leverage while walking and jumping. During these activities, the sesamoid bones carry much of the body’s weight, which is why it is concerning when they become irritated or fractured.

Causes

There are three types of Sesamoid Injury that can occur within the foot and each one is caused by different factors:

• Turf toe. This is an injury of the soft tissue surrounding the big toe joint. It usually occurs when the big toe joint is extended beyond its normal range.
• Fracture. A fracture (break) in a sesamoid bone can either be acute or chronic. An acute fracture is caused by trauma where there is a direct blow or impact to the bone. This may be caused by landing too hard on the foot after a jump or fall. Meanwhile, a chronic fracture is a  stress-related fracture; a hairline break that is usually caused by repetitive stress or overuse.
• Sesamoiditis. This is an overuse injury involving chronic inflammation of the sesamoid bones and the tendons involved with those bones. Sesamoiditis is caused by increased pressure on the sesamoids. This can result from running, jumping, dancing or wearing high-heeled shoes.

Symptoms

A sesamoid bone injury can be a very painful experience. An acute fracture produces an immediate pain and swelling at the site of the break but usually does not affect the entire big toe joint. On the other hand, a chronic sesamoid fracture produces long standing pain in the ball of the foot beneath the big toe joint. The pain tends to come and go, becoming aggravated during activity and relieved while resting.

Another sesamoid injury, turf toe, causes immediate, sharp pain and swelling. It usually affects the entire big toe joint and limits the motion of the toe. A patient with sesamoiditis shows symptoms like that of a chronic fracture.

Potential Treatments

In diagnosing a sesamoid injury, your doctor will ask you about your symptoms, medical history and activities. The foot and ankle surgeon will examine the foot focusing on the big toe joint. The surgeon will press on the big toe, move it up and down, and may assess the way you walk. He may also evaluate the wear pattern of your shoes. An x-ray will be ordered and in some cases advanced imaging studies may be required too.

If you need help in treating your sesamoid injury, contact a doctor as soon as possible.