Sesamoiditis - Diagnosis
This condition produces sharp pain under the ball of the big toes on the push-off phase of walking, or it you rise up on your toes. Generally it is more common in high arch feet, but it can affect many different shaped feet. There are two little bones found under the 1st metatarsal that are embedded in a muscle called flexor digitorum brevis. The bones are called the tibial or medial sesamoid, and the fibular or lateral sesamoid. This flexor digitorum brevis muscle sits under the arch of the foot and helps pull the big toe firmly into the ground as you rise up onto the ball of your foot. The two little spherical bones act as pulleys that change the pull of the tendon depending on the position of the foot and big toe, just like your knee-cap bone does at the knee. They make the muscle work more efficiently.
If the muscle is weak, or the foot an awkward shape like high arched, then sometimes the bones don’t pull out of the way before you rise up on the metatarsal head. The result is the bones can get crushed under the metatarsal head becoming painful. More rarely the tendon pulls too hard and breaks the sesamoids by pulling them apart. One slight complicating fact is although in most people each of these two bones are one complete bone, in some people each bone can be made of two or more parts which can make them look fractured when they are not.
Sesamoiditis - Treatment
Sesamoiditis can usually be settled with exercises to strengthen flexor digitorum brevis, insoles with padding put in just the right place and suitable footwear with padded soles. More stubborn cases may need a steroid injection, or worse case scenario, surgery. Surgery usually consists of thinning the offending bone, or removing it.