The ethyology of the avascular necrosis of the femoral head

Abstract

Introduction. Avascular necrosis (AVN) is the disease characterized by a vascular insult to the blood supply of the femoral head, which can lead to necrosis of the spongiform bone followed by collapse of the femoral head with degenerative changes. It has been estimated that approximately 10 000 to 20 000 new cases are diagnosed in the USA each year and there are 300 000 – 600 000 people diagnosed with AVN. Aim of the study. To elucidate the actual status in etiology of AVN of femoral head. Material and methods. The following databases were used for articles search: Pubmed, Embrase, Hinary, Web of Science, Medline, Sciencedirect, for searching articles. We have selected and studied 74 articles containing the keywords: AVN of the femural head, etiology of AVN, genetic disorders in AVN. Results. Traumatic aseptic necrosis of the femoral head appears as results of mechanical disruption of blood flow to the femoral head. The non-traumatic causes of secondary AVN of the femoral head are: chronic alcohol consumption (20–40%), corticosteroid therapy (35–40%), after organ transplant, haematologic disease (anemia, polycythemia, hemophilia, thalassemia), clotting diseases, connective tissue disease, infiltrating diseases; some endocrine diseases (Cushing disease, hyperparathyroidism), metabolic diseases (gout, hyperuricemia, high cholesterol), congenital diseases (congenital sprain hip joint, Legg–Calvé–Perthes disease), Caisson disease, pancreatitis, chronic renal failure, hemodialysis, chronic liver disease, HIV infection, pregnancy, chemo- and radio- therapy, thrombophlebitis. Approximately 10 to 20% of cases do not have any identifiable risk factors and are therefore considered to be idiopathic in nature. It has been shown that some genes are involved in the pathogenesis of AVN: ADH2, ADH3, ALDH2 and P450E1. These genes are involved in the alcohol metabolism and polymorphisms of these genes have been associated with the risk of AVN. Jones et al. found that approximately 82% of patients in their study had at least one coagulation factor abnormality. Familial forms of AVN of the femoral head appear to be very rare, with only a few families reported in the medical literature. Liu et all. noted that a COL2A1 gene mutation in certain families predisposed to development of AVN of the femoral head by autosomal dominant transmission. Conclusions. 1. Avascular necrosis of the femoral head is especially common among young people, affecting mainly men. Often an underlying cause cannot be determined. 2. Aseptic necrosis of the femoral head is a disease whose etiology is not completely elucidated while the actual role of the genetic disorders in this pathology is to be determined.