Freiberg's disease
Freiberg's disease, sometimes called Freiberg's infraction, is an uncommon cause of forefoot pain. It sometimes occurs in teenage years and is more common in girls than boys. The complaint is usually of pain and stiffness at the base of the second toe. Discomfort is worst when active, particularly when flexing the toe joints such as while walking up hill or running. Onset is sometimes related to an injury but most often develops spontaneously over a period of weeks or months. There might be swelling on the top surface of the foot at the base of the toe and this tends to become firm and hard with time. The cause is unknown but involves a crumbling process in the end of the bone (metatarsal) which forms the ball of the forefoot and upon which the toe is mounted. For a while the core of the bone is weak and so it tends to crumble to some degree while new bone grows in to alleviate the weakness.
The amount of bone collapse and formation of new bone at the base of the toe determines the end result. This end part of the bone forms the toe joint so if by the time it heals it is no longer rounded, the toe will be much stiffer and tends to catch painfully on the bony spurs. The lumps of new bone can be large enough to press on the underside of the shoe.
Once the inflammed period is over and the bone has healed, further treatment might not be necessary. There is likely to be some restriction in the range of movement of the toe but this is not always a problem. If discomfort and significant stiffness do persist the situation can usually be improved surgically. This involves removing the bony spurs which are blocking the toes movement (cheilectomy) plus any cartilage debris and lose fragments of bone resulting from the crumbling process.