The main joint of the big toe (great toe) forms the inside edge of the ball of the foot There is one sesamoid bone on each side of the base of the big toe, the tibial and fibular sesamoids. They look like small navy beans. They are embedded in the tendon of the Flexor Hallucis Brevis muscle just under the base of the big toe. These sesamoid bones are similar to a knee cap in that, they float around and are connected only to tendons or are embedded in muscle (there is no joint). There are 2 grooves on the bottom of your first metatarsal bone in which the sesamoid bones are seated but they are not attached. These little bones serve 2 main purposes. The toe flexor muscles bend and pass underneath the main joint of the big toe (view pictures), crossing over the hump that is formed by the sesamoid bones. This hump acts as a fulcrum point for the toe flexors, giving these muscles extra leverage and power. They also act as a fulcrum for the short flexor tendon. The sesamoids in the forefoot ease friction, assist with weight bearing and elevate the bones of the big toe.
Causes of Sesamoiditis
These bones are accustomed to massive pressure because of the leverage that is placed upon them. Any type of exertion that propels the body forward and upward involves the Sesamoid bones and tendons. Occasionally they can become irritated. Any activity where pressure is placed on the ball of the foot and the large toe is flexed continuously aggravate the bones and tendons. Catchers in baseball and ballerina’s are famous for getting Sesamoiditis. This is basically an overuse injury so even walking and running can cause it.
- Over Pronation (walking on the inside of the foot) adds excessive pressure to the big toes.
- High Arches: can concentrate more pressure to the big toe. You are more prone if you notice that the big toe has become stiff.
- Loss of Padding. As a person becomes older they lose some of the padding in the bottom of their feet and become more prone to a sesamoid injury.
- Arthritis: If it develops between the sesamoid bones and the big toe, there will be friction and pain
- Stress Fractures: The sesamoid bones can become fractured from over exertion or any activity with sudden directional changes, like basketball, tennis, or dancing.
- Traumatic Fractures: Involve a sudden impact. Like jumping off a wall.
- Sesamoiditis typically starts with a dull pain under the big toe joint. The sesamoids will feel tender to the touch. Any added weight or pressure to the sesamoids will cause increased pain, usually felt when the heel leaves the ground.
- Other Symptoms:
- A catching or popping that is followed by increased pain, which usually subsides after the foot is rested.
- Swelling and bruising
- Impaired ability to bend or straighten your big toe
- When numbness is felt in the web of the first two toes.
- Stopping the activity that causes the pain
- Icing the sole of your foot.
- Purchase a cushioning pad to relieve the weight.
- Use cushioning foot orthotics to relieve stress. A custom therapeutic orthotic is highly recommended as it will change your gait if needed, put more stress on the arch of the foot and relieve stress from the big toe.
- Aspirin or ibuprofen to relieve the pain.
- Tape the big toe in a downward direction.
- Consider a steroid shot
- Pneumatic walker with rocker sole when walking. 2 to 6 weeks may be required.
Fracture of the Sesamoid:
- Wear a short leg fracture brace, for up to 12 weeks. If pain persists use crutches even with the brace.
- After 8-12 weeks. If the stress fracture won’t heal and is separated (nonunion fracture). Surgery is most likely the outcome. To avoid surgery doctors will want a cast and limited weight applied to the foot.
When Is Surgery Needed?
When the injury fails to respond to conservative treatment, surgery may be required as a last resort. Your surgeon may recommend removing part or all of the sesamoid bone. If only one sesamoid bone is removed the other sesamoid bone can still provide a fulcrum point for the toe flexors. Surgeons will avoid taking both bones out if possible because the toe flexors lose necessary leverage and can’t function. Therefore Claw Toe can develop.
If you have had sesamoiditis and/or surgery please share with us your experiences.