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.
When there is not sufficient blood supply to the bone the normal weight-bearing stress can cause pain, therefore reducing the stress on the affected area of the foot is crucial. This can be achieved by adjusting the footwear and insoles but also by physiotherapy to work on certain muscles to reduce the weight bearing stress on the affected area of the foot. In case the bone settles but does not regain its normal shape the adjacent joints might become arthritic resulting in further pain. If conservative treatment fails to provide sufficient pain relief an operation will become a good option. Fusing the arthritic bone and joint to the neighbouring bone will eliminate the pain and allow pain-free mobilisation of the foot.
