Actonel risedronate: Post-marketing study data

A task force of the American Society for Bone and Mineral Research reported a review of both published and unpublished data suggesting that the risk of atypical femoral fractures increases with the duration of exposure to bisphosphonates for osteoporosis. Specifically, a review of 310 cases of atypical femur fractures showed that 94% of patients had taken bisphosphonates for >5 years. The report also noted that more than half of patients with atypical femur fractures reported groin or thigh pain for a period of weeks or months before fractures occurred.

Additionally, preclinical data evaluating the effect of bisphosphonates on matrix composition and mechanical properties of bones showed a potential association between prolonged use of the drugs and atypical femur fractures. ...