Background:Avascular necrosis (AN) is a disease, which is the result of blood flow disturbance and necrosis of the bone tissue. It affects predominantly men of working age and steadily progresses to secondary osteoarthritis. AN is a multifactorial disease. In the context of vascular hypothesis it is of particular interest to evaluate homocysteine and its metabolism in patients with AN.Objectives:The aim of the present study was to evaluate some parameters of endothelial function in patients with AN of the femoral head or femoral condyles in order to determine possible treatment and prevention options.Methods:We included 53 patients with AN of the femoral head or femoral condyles into the study. The patients were aged 49 (35-62) years, 58,49% (n=31) were male. The inclusion criteria was diagnosis of AN confirmed by X-Ray, CT or MRI. The exclusion criteria were: traumatic AN, Legg-Calve-Pertes disease, connective tissue systemic diseases. We recruited 51 patients into the control group. The groups were comparable by age and gender. In order to analyse engothelial function in the groups we investigated the following serum parameters: homocysteine, vitamin B12, folate. In order to analyse the data obtained we used non-parametric statistics.Results:We determined a higher level of homocysteine in patients with AN (12,15 (7,55-14,60) vs. 8,18 (6,57-10,70) mcmol/l in the control group, p=0,04). Also we observed almost equal levels of vitamin B12 in patients with AN an in the control group (531,95 (340,80-793,55) vs. 532,75 (417,60-669,7) pg/ml, p=0,99). The level of folate was lower in the study group (5,66 (3,83-6,83) vs. 6,99 (5,02-10,38) ng/ml, p=0,01).Conclusion:The data obtained show that homocysteine level in patients with AN is higher. This can be a consequence of folate deficiency, which takes part in homocysteine metabolism. Therefore, homocysteine metabolism disturbances can lead to endothelial dysfunction, which results in cardiovascular events in the heart, brain, kidneys [1] as well as in the bone, according to the study results. Folate supplement is the possible way of AN treatment and prevention.References:[1]Nowroozpoor A, Gutterman D, Safdar B. Is microvascular dysfunction a systemic disorder with common biomarkers found in the heart, brain, and kidneys? - A scoping review. Microvasc Res. 2021 Mar;134:104123. doi: 10.1016/j.mvr.2020.104123. Epub 2020 Dec 15. PMID: 33333140.Disclosure of Interests:None declared