Heel calluses, also called plantar calluses, develop when one metatarsal bone is longer or lower than the others and it hits the ground with more force than it is equipped to handle-at every step. As a result, the skin under this bone thickens like a rock in your shoe. The callus causes irritation and pain.
Sometimes, a procedure called an osteotomy is performed to relieve the pressure on the bone. The procedure involves cutting the metatarsal bone in a "V" shape and lifting the bone and aligning it with the other bones.