OBJECTIVETo review the recent developments in the mechanisms of glucocorticoids induced osteonecrosis of femoral head (ONFH) and introduce a new theory of ONFH.

DATA SOURCESBoth Chinese- and English-language literatures were searched using MEDLINE (1997 - 2011), Pubmed (1997 - 2011) and the Index of Chinese-language Literature (1997 - 2011).

STUDY SELECTIONData from published articles about mechanisms of glucocorticoids induced ONFH in recent domestic and foreign literature were selected. Data extraction Data were mainly extracted from 61 articles which are listed in the reference section of this review.

RESULTSGlucocorticoids are steroid hormones secreted by the adrenal cortex that play a pivotal role in the regulation of a variety of developmental, metabolic and immune functions. However, high dose of exogenous glucocorticoids usage is the most common non-traumatic cause of ONFH. Glucocorticoids can affect the metabolisms of osteoblasts, osteoclasts, bone marrow stromal cells and adipocytes which decrease osteoblasts formation but increase adipocytes formation and cause ONFH finally.

CONCLUSIONSGlucocorticoids affect the differentiation of mesenchymal stem cells, through activating or inhibiting the related transcript regulators of osteogenesis and adipogenesis. At last, the size and volume of mesenchymal stem cells derived adipocytes will increase amazingly, but the osteoblasts will be decreased obviously. In the meantime, the activity of the osteoclasts will be activated. So, these mechanisms work together and lead to ONFH.