Atypical femoral fractures: risks and benefits of long-term treatment of osteoporosis with anti-resorptive therapy

Modern osteoporosis treatment began in the mid-1990s with the approval of amino-bisphosphonates, anti-resorptive agents that have been shown to decrease osteoporotic fracture risk by about half. In 2005, the first cases of atypical femoral fractures (AFF), occurring in the shaft of the femur, were reported. Since then, more cases have been found, leading to great concern among patients and a dramatic decrease in bisphosphonate prescribing. The pathogenesis and incidence of AFF are reviewed herein. Management and an approach to prevention or early detection of AFF are also provided. Denosumab, a more recently approved anti-resorptive medication has also been associated with AFF. Long-term management of osteoporosis and prevention of fracture are challenging in light of this serious but uncommon side effect, yet with an aging population osteoporotic fracture is destined to increase in frequency.