Long standing diabetic patients tend to develop diabetic neuropathy. The weight bearing portion of the foot is commonly affected. It tends to have a periarticular bony involvement which during the early stages are difficult to distinguish from osteomyelitis.  However as more progressive destruction occurs, the periarticular distribution becomes more evident and is confined to the mid foot. 

Altered marrow signals in bone may be seen in neuropathy alone due to reactive osteitis. However extension of marrow signal changes to hind foot should always raise the possibility of osteomyelitis. 

Of course, a neuropathic joint is more prone to osteomyelitis than a healthy one. 

The development of a sinus track along the cuboid is a way for the infection to decompress itself, what we call empyema necessitans. (an innate mechanism to drain infection from the body). 

More and more bones of the foot will be prone for spread for infection and urgent intervention is necessary.