Avascular osteonecrosis is a serious disorder affecting mostly middle-aged individuals. It is characterized as death of bone cells and bone marrow cells with subsequent bone collapse. Alteration of subchondral bone blood supply is responsible for this process. Development of atraumatic osteonecrosis is associated with wide range of conditions including systemic use of glucocorticoids. Pathogenesis of glucocorticoid induced osteonecrosis is not fully understood yet. On the basis of experimental data, it seems that altered lipid metabolism, changes in coagulation, fibrinolysis, and microcirculation or direct affection of bone cells may play an important role. It is probably based on local alteration of gene transcription induced by glucocorticoids. Causal relationship between use of glucocorticoids and subsequent osteonecrosis in human medicine was not and even could not have been demonstrated yet. It is based on the fact that the diseases alone could also predispose to osteonecrosis. An association between the use of glucocorticoids and occurrence of osteonecrosis is rather high, particularly in the cases of multiple osteonecrosis (up to 91 %). Patients treated with intravenous pulses of methylprednisolone and with initial high daily doses of oral glucocorticoids are most susceptible for the development of osteonecrosis. Cumulative or mean daily doses play probably less important role. Osteonecrosis is slowly progressive process that may develop asymptomatically during several months or years. Thanks to modern imaging methods (magnetic resonance), it is possible to diagnose early phase of osteonecrosis within two to three months after glucocorticoids exposure. Reparative changes occur in the beginning of the necrotic process, which may be reversible at this stage. If it progresses, subsequent bone collapse makes the process irreversible. For further prognosis, it is crucial to diagnose the disease early, in reparative and mostly asymptomatic phase. Uncommon, however due to its severe course, significant phenomenon represents multiple osteonecrosis that is mostly discussed in this overview. The whole problem of multiple osteonecrosis and osteonecrosis associated with glucocorticoids is documented with two case reports.

        Key words: osteonecrosis, glucocorticoids, multiple osteonecrosis