Brachymetatarsia is the condition where one of the bones that comprise the "ball" of the foot (the metatarsal) is abnormally. There are five metatarsal bones, and the one that is most commonly associated with brachymetatarsia is the fourth metatarsal.
Brachymetapody is the condition where two or more metatarsals is short.
The most common cause of brachymetatarsia is when the growth plate of the bone stops growing too soon. This may be caused from trauma, infection or a genetic predisposition.
Second, a short metatarsal means that the toe will be short, too. This will present an odd appearance, so there are aesthetic concerns. Second, a short toe tends to drift upwards to the top of the foot, and this may make shoe buying difficult.
If the primary complaint is pain in the ball of the foot where the other metatarsals have to bear excessive weight, accommodative padding or accommodative orthoses are useful. They'll transfer weight away from the sore area. If the primary complaint is difficulty with shoes, extra depth or even custom made moulded shoes may be considered.
Another treatment option is to lengthen the short metatarsal. This may be done by cutting the short metatarsal in such a way where it may be slid into a better position, then held with fixation, or by inserting a bone graft to provide extra length, or by callus distraction, where the bone is lengthened slowly over time with the use of a mini-external fixation device.