Atypical diaphyseal femoral fractures--new aspects.

Post menopausal osteoporotic fractures are a major public health concern worldwide with oral bisphosphonates favored for their prevention and treatment. Recent interest has centered on clinically observed, unusually sited femoral diaphyseal fractures, particularly attributed to alendronate. Their imaging presentations on routine radiographs, alternate imaging modalities, and associated pitfalls in nine fractures in six patients are selectively illustrated by seven fractures in four patients that serve to emphasize the following: (1) Bisphosphonates other than alendronate have been used for treating various bone diseases in children and men as well as osteoporotic women. (2) Effects may differ with each bisphosphonate's route of administration and prolongation of activity, despite discontinuation. Prior investigations and theoretical mechanisms of bisphosphonates as a class rather than with a specific alendronate association are reviewed to provide a broader basis for evaluating their recently observed clinical and radiographic complications.