Avascular necrosis of the foot and ankle: aetiology, investigation and management

Abstract

Avascular necrosis (AVN) of the foot and ankle can pose both a diagnostic challenge, and a management dilemma. This paper seeks to describe the various types of AVN in the foot and ankle and clarify the expected presentation, examination findings, investigations and management strategies available. In addition, discussion of the relevant basic sciences, and the process of bone healing will facilitate a broader understanding of the condition, and the risk factors for its development. AVN can be secondary to trauma, as in most cases of talar AVN, or secondary to factors such as steroid use, alcohol excess, metabolic diseases, repetitive microtrauma, and abnormal biomechanics. Usually, a combination of the above is thought to be responsible. Many of the conditions described are established in childhood, either presenting at the time, or in the third or fourth decade. Management ranges from exercise limitation and offloading footwear, to surgical decompression, osteotomy, fusion or excision. AVN has a high morbidity and affects a young demographic, causing a substantial burden on healthcare. Early recognition of symptoms, and appropriate investigation and management could reduce the number of patients progressing to advanced disease, avoiding the frequently unsatisfactory surgical outcomes associated with options such as fusion and excision.