Disentangling the emerging evidence around atypical fractures.

Atypical femur fractures are rare but a growing concern, as they are more common in patients who use bisphosphonates. The best radiology-based studies have had access to only short-term exposure data, while the studies using prescription databases with substantial long-term data did not have access to radiology reports. The interests of the patients are probably best served by reserving long-term bisphosphonate treatment for patients who are at the highest risk of osteoporotic fractures and considering drug holidays after 5 years in patients at low risk. Recent studies have further strengthened the case for active medical or surgical therapy in patients with incomplete fractures, but patient numbers are small, and randomized controlled trials may not be forthcoming in the immediate future. The recommendations made to establish an international database for such fractures have not yet been followed, and more epidemiologic and pathophysiologic research is needed.