Hammer, claw, and mallet toe surgery refers to a series of surgical procedures performed to correct deformed toes.

There are three main forms of toe abnormalities in the human foot: hammer toes, claw toes, and mallet toes. A hammer toe, also called contracted toe, bone spur, rotated toe, or deformed toe, is a toe curled as the result of a bend in the middle joint. It may be either flexible or rigid, and may affect any of the four smaller toes. The joints in the toe buckle due to tightening of the ligaments and tendons, which points the toe upward at an angle. The patient's shoes then put pressure on the prominent portion of the toe, leading to inflammation, bursitis, corns, and calluses. Mallet toes and claw toes are similar to hammer toes, except that different joints on the toe are affected. The joint at the end of the toe buckles in a mallet toe, while a claw toe involves abnormal positions of all three joints in the toe.

From http://www.answers.com/topic/hammer-claw-and-mallet-toe-surgery