For various reasons at times the blood supply to certain bones in the foot can be compromised and result in a so-called avascular necrosis (AVN) of the bone. This can lead to a crumbling of the bone and can cause pain, swelling and inability to fully weight bear on the foot. There is not a universal explanation for the occurrence of the problem but repetitive micro-stress may play a role.
With time the bone will regain some blood supply and reform but not back to its normal shape. The bones that are most commonly affected are the 2nd metatarsal head (ball of the foot, called Freiberg disease), the sesamoids (under big toe) or the navicular bone (hindfoot, called Mueller-Weiss syndrome). The severity and duration of symptoms can vary remarkably.