To the Editor: The study by Dr Park-Wyllie and colleagues1 on the epidemiology of subtrochanteric and femoral shaft fractures in 205 466 women receiving oral bisphosphonates provides reassurance that the absolute risk of subtrochanteric fractures among bisphosphonate users is low. In our view, however, it has 2 major limitations.
First, the authors did not have access to radiographs and therefore could not differentiate typical osteoporotic fractures from characteristic atypical fractures. In a 5-year retrospective study of 152 nonhip femur fractures, we found, after careful review of individual radiographs, that 20 of the fractures were atypical.2 A case-control study of 63 patients with low-energy subtrochanteric/femoral shaft fractures and 126 controls with hip fractures reported that 16% of subtrochanteric and 1.1% of all femur fractures seen at 1 center over a 10-year period were atypical on the basis of radiographic analysis.3 Therefore, careful review of individual radiographs is essential in the identification of atypical fractures.
Girgis CM, Seibel MJ. Bisphosphonate Use and Femoral Fractures in Older Women. JAMA. 2011;305(20):2068-2069. doi:10.1001/jama.2011.673