PATHOGENESIS

The exact mechanism of the pathogenesis of NAC is not yet established

Two theories try to explain its pathogenesis: the Neurotraumatic theory (German) and the Neurovascular theory (French) It is currently considered that both theories may play an important role in the pathogenesis of CNA

According to the Neurotraumatic theory, bone destruction is due to sensory loss associated with repetitive mechanical traumas of the foot

Imperceptible trauma combined with weight bearing on the affected limb will cause fractures and joint destruction characteristic of this pathology

On the other hand, in the Neurovascular theory, joint destruction will be caused by a vascular reflex secondary to an autonomous neurological dysregulation (sympathectomy) that will cause hyperemia and periarticular osteopenia through the activation of osteoclasts, which facilitates the occurrence of fractures with trauma

Autonomic neuropathy results in osteopenia that, associated with the loss of protective sensation caused by sensory neuropathy, predisposes to bone destruction that occurs during gait, as the patient is not aware of the trauma Thus, CNA results from this vicious cycle in which the patient continues to walk on the diseased foot, allowing for more lesions to appear

It should be noted that the resulting dysfunction of the intrinsic muscles of the foot causes overload in certain areas, leading to the appearance of microfractures, ligament laxity and progression to bone destruction.