Subtrochanteric atypical femoral fracture induced solely by glucocorticoid without bisphosphonate treatment: a case report.

An AFF is a form of stress fracture induced by excessive physiologic repetitive stress over the bone remodeling capacity. Although glucocorticoid administration is a known risk factor for AFF, no case of AFF with glucocorticoid administration as the only risk factor has been previously reported. In this report, we aimed to highlight the risk of AFF associated with long-term administration of glucocorticoids, and the importance of surveillance and correction of risk factors in patients undergoing long-term glucocorticoid therapy. A 58-year-old male patient was diagnosed with subtrochanteric AFF. He had no medical history of any condition that might disrupt bone metabolism and no known risk factors for AFF, except for long-term administration of glucocorticoid. After fixation of the fracture, the glucocorticoid was replaced with an alternative medication. Although AFF is notorious for delayed union or nonunion, complete union of the fracture was obtained at 14 months postoperatively. This case brought to our attention the possibility that glucocorticoids alone may be responsible for inducing AFF and highlighted the importance of regular assessments in case of necessity of glucocorticoid administration. Additionally, correction of risk factors might expedite the union of AFF.