Avascular Necrosis of the Femoral Head
Avascular necrosis (AVN) or osteonecrosis of the femoral head is characterised by cellular death and subsequent femoral head collapse caused by interruption of bone blood supply. It affects young adults, usually in the third and fourth decade of their life. Bilateral hip involvement reached up to 80% within 2 years. Direct causes of AVN include trauma, haematologic diseases (haemoglobinopathies, leukaemia, lymphoma), dysbaric disorders and storage disorders (Gaucher’s disease), and indirect causes include coagulation disorders, alcohol abuse, smoking, pregnancy, steroids (endogenous or exogenous), systemic lupus erythematosus and organ transplantation. When the underlying cause of AVN is not well defined, the diagnosis of idiopathic AVN is considered. Despite the young age of patients, THR remains the only method of treatment for the advanced stages of the disease.