The most common factors causing or contributing to nontraumatic osteonecrosis are Corticosteroid use (particularly with prolonged use and / or higher doses) Excessive alcohol consumption Other nontraumatic risk factors for osteonecrosis include Chemotherapy Coagulation disorders (eg, antiphospholipid syndrome, inherited thrombophilia, hypofibrinolytic disorders) Cushing syndrome Decompression sickness Dyslipidemia Gaucher disease Hemoglobinopathy (eg, sickle cell disease) HIV infection Liver disease Organ transplantation Pancreatitis Radiation Smoking Systemic lupus erythematosus (SLE) and other autoimmune connective tissue disorders Tumors Miscellaneous disorders (eg, chronic kidney disease, rare inherited metabolic disorders) The contribution of corticosteroid use to the risk of osteonecrosis is increased when the dose of prednisone or an equivalent corticosteroid is > 20 mg / day for several weeks or months, resulting in a cumulative dose usually > 2000 mg, although case reports have described osteonecrosis subsequent to much less corticosteroid exposure.