A sesamoid is a bone embedded in a tendon. Sesamoids are found in several joints in the body where motion is required. In the foot, the sesamoids are two small round bones located in the ball of the foot, beneath the big toe joint. They act as a pulley for the tendons that run under the ball of the foot. They provide leverage when the big toe “pushes off” during walking and running. The sesamoids also serve as a weight-bearing 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 can involve the bones, tendons, and/or surrounding tissue in the joint. They 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.
There are three main types of sesamoid injuries in the foot:
- Turf toe – 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 due to impact or landing awkrawdly. Turf toe causes immediate, sharp pain and swelling. It usually affects the entire big toe joint and limits the motion of the toe. Sometimes a “pop” is felt at the moment of injury.
- Fracture – A fracture in a sesamoid bone can be either acute (sudden impact) or chronic (repetitive stress resulting in hairline fracture).
- Sesamoiditis – An overuse injury involving chronic inflammation of the sesamoid bones and the tendons involved with those bones. Sesamoiditis is caused by increased pressure to the sesamoids and is associated with a dull pain beneath the big toe joint. The pain may come and go and can be aggravated by certain types of activity.
- Padding, strapping, or taping. A pad may be placed in the shoe to cushion the inflamed sesamoid area, or the toe may be taped or strapped to relieve that area of tension.
- Rest from aggravating activity or training modifications.
- Immobilization. The foot may be placed in a cast or removable walking cast. Crutches may be used to prevent placing weight on the foot if fractured or severe pain.
- Ice therapy
- Medications. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, are often helpful in reducing the pain and inflammation.
- Exercises (range-of-motion, strengthening, and conditioning) and/or ultrasound therapy.
- Steroid injections. In some cases, cortisone is injected in the joint to reduce pain and inflammation. Short term relief for severe pain but is not treating underlying cause of pain.
- Custom orthotic Insoles that fit into the shoe may be prescribed for long-term treatment of sesamoiditis to balance the pressure placed on the ball of the foot and allow effective gait.
- Lifestyle modifications.