Avascular necrosis (AVN) of the femoral head is a disease, characterized by the death of osteocytes and bone marrow, leading to collapse of the femoral head and dysfunction of the hip joint. There are many known risk factors for the development of this disease including trauma of the hip joint, hemoglobinopathy, alcoholism, taking corticosteroids, collagenosis, etc. Conservative treatment (drug therapy using vascular drugs, bisphosphonates, chondroprotectors, NSAIDs, physiotherapy, exercise therapy) is shown for any stage of the hip AVN, however, surgical treatment has a higher potential. The key to successful treatment is the detection of AVN at an early (pre-collapse) stage to prevent subsequent collapse by performing organ-sparing surgical interventions that reduce the rate of disease progression and allow delaying of the hip replacement. The literature describes a number of organ-preserving operations performed at an early stage of AVN. Currently, there are three main areas of surgical treatment of this disease: classical decompression of the femoral head, decompression using various types of grafts and combined treatment using various cellular technologies. This literature review is devoted to the consideration of the indications for implementation, as well as the results of treatment of patients using the above techniques.

Introduction. Among the etiological factors of non-traumatic avascular necrosis of the femoral head are the following: the prolonged use of corticosteroids, alcohol abuse, systemic lupus erythematosus, sickle cell anemia, the Legg Calve Perthes disease, ionizing radiation, cytotoxic agents, etc. At the same time necrosis of the femoral head might occur in the absence of the above factors (idiopathic necrosis). The reasons for idiopathic avascular necrosis could be a mechanical obstacle to the flow of blood, thrombotic occlusion of vessels, extravascular compression. The purpose of this study is to examine the role of C677T gene mutation of the MTHFR gene in the development of non-traumatic avascular necrosis of the femoral head. Materials and methods. During this study there was a comparative analysis of the frequency of the C677T gene allelic variants conducted in 41 patients with a verified diagnosis of non-traumatic avascular necrosis (main group) and 320 healthy individuals (control group). The survey program included the study of polymorphisms of MTHFR C677T gene by PCR. Results. Differences in the frequency of occurrence of C allele of C677T gene MTHFR in the heterozygous state in case of non-traumatic avascular necrosis and in its absence were not statistically significant (51.2% against 37.2% respectively, 2 = 3.014, p = 0.083). The genotype TT (T in the homozygous state) of the C677T MTHFR gene was detected in 19.5% of the main group patients. A similar index in the control group was two times lower and amounted to 9.0 percent, the differences between groups statistically significant, 2 = 4.314, p = 0.038. Conclusion. The study showed the importance of having the T C677T MTHFR gene in the pathogenesis of non-traumatic avascular necrosis of the femoral head. The data obtained and the analysis of the current literature suggests that this polymorphism is one of genetic predictors of non-traumatic avascular necrosis of the femoral head and other cardiovascular diseases as well.