Dancers pretty much abuse their feet, with repetitive forces in unnatural poses, so it is no surprise that they end up with stress fractures in their feet. When we think about broken bones in the foot, most of us picture a broken toe or a large bone in the middle of the foot (the metatarsals). However, there are two tiny pea-like bones that can also be broken- the sesamoid bones. These little bones are embedded side by side within the tendon that is in the ball of your foot, just beneath the base of your big toe. They act like pulleys, allowing the tendon to slide more easily as you bend your foot, pushing off with running, jumping or walking. Stress fractures of the sesamoid bones show up as gradually increasing pain every time you put pressure on them, especially with the act of bending and pushing off. The pain tends to stay very localized, is relieved with rest, and the maximal tenderness to touch is underneath the base of your big toe.
How are these fractures diagnosed?
Sesamoid fractures, like all stress fractures, may not show up on x-rays till they have been present for a couple of weeks. A dark line is seen within the white "ball" that is the sesamoid bone. Occasionally the sesamoid bone will be completely broken into two parts, and these fractures may require surgical correction.
What is the treatment?
There is no quick fix for this problem, much to the dismay of dancers (and runners). The treatment is to stop bending the ball of your foot, most easily accomplished with a firm walking boot. How long? Typically a minimum of 3 weeks, but more often roughly 6 weeks. Upon return to activity, the key is to "start low and go slow"- do NOT jump back in to full workouts!
BOTTOM LINE: For deep, persistent, worsening pain under the ball of your foot, consider the possibility of a stress fracture of your sesamoids- head to your family doctor for an exam and possible X-ray.