What is a Sesamoid?
A sesamoid is a bone embedded in a tendon. Sesamoids are found in several joints in the body. In the foot, the sesamoids are two pea-shaped bones located in the ball of the foot, beneath the big toe joint.

Acting as a pulley for tendons, the sesamoids help the big toe move normally and provide leverage when the big toe “pushes off” during walking and running. The sesamoids also serve as a weightbearing surface for the first metatarsal bone (the long bone connected to the big toe), absorbing the weight placed on the ball of the foot when walking, running, and jumping.

Sesamoid injuries—which can involve the bones, tendons, and/or surrounding tissue in the joint—are often associated with activities requiring increased pressure on the ball of the foot, such as running, basketball, football, golf, tennis, and ballet. In addition, people with high arches are at risk for developing sesamoid problems. Frequently wearing high-heeled shoes can also be a contributing factor.

Types of Sesamoid Injuries in the Foot
There are three types of sesamoid injuries in the foot:

Diagnosis

In diagnosing a sesamoid injury, 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 patient’s walking and evaluate the wear pattern on the patient’s shoes. X-rays are ordered, and in some cases, additional imaging studies—such as a bone scan or MRI—may also be needed.

Treatment: Non-Surgical Approaches

Non-surgical treatment for sesamoid injuries of the foot may include one or more of the following options, depending on the type of injury and degree of severity:

When is Surgery Needed?
Surgery is generally reserved for the most severe sesamoid injuries which fail to respond to non-surgical treatment over a long period of time. In these cases, the foot and ankle surgeon will determine the type of procedure that is best suited to the individual patient.

This information has been prepared by the Consumer Education Committee of the American College of Foot and Ankle Surgeons, a professional society of 5,700 podiatric foot and ankle surgeons. Members of the College are Doctors of Podiatric Medicine who have received additional training through surgical residency programs. The mission of the College is to promote superior care of foot and ankle surgical patients through education, research and the promotion of the highest professional standards. Copyright © 2004, American College of Foot and Ankle Surgeons, www.acfas.org