Metabolic bone disease: atypical femoral fractures

Since 2005 reports have been published describing unusual femoral shaft fractures primarily in postmenopausal women treated for prolonged periods with a bisphosphonate drug for osteoporosis. In some patients pain develops in the femur prior to a completed fracture. Bilateral fractures have occurred in some patients. It is unclear whether oversuppression of bone cell activity is a major factor in the pathogenesis of the fractures, or whether these are a rare manifestation of the underlying bone disease. Such fractures do occur in other metabolic bone disorders in which there are marked abnormalities of bone structure.