Background Biphosphonates are considered the first line treatment for osteoporosis. One of the side effects of the continuous treatment is the development of atypical fractures. These are generally subtrochanteric, although they can appear anywhere in the femoral diaphysis, with a low prevalence (1.1% of all the femur fractures). Their incidence grows with the time to exposure to bisphosphonates. Radiologically they show a traverse trace or slightly oblique, non comminuted with formation of a medial spicule and the majority of the cases show thickness of the lateral cortical. They appear after a minimum traumatism or spontaneously.
Objectives To determine the prevalence or atypical fractures according to the American Society of Mineral and Bone Research (ASMBR) criteria between 2011 and 2014 in the Universitary Hosptial of Donostia (Guipúzcoa, Spain).
Methods Retrospective research of clinical data of patients operated of hip fracture and/or femur fractures between November 2011 and December 2014 Variables included were: age, sex, race, clinical features, treatment received, and presence or absence of diseases and pharmacological treatments that participate in the bone remodeling.
Results 921 patients operated of hip fracture and 76 of diaphyseal fracture. 6 patients met the clinical and radiologic criteria of the ASMBR for an atypical fracture, 100% of these had recieved a long term treatment with biphosphonates and ment the 6,57% of the diaphyseal fractures, the 0,12% of the hip fractures and the 0,6% of the total of the fractures studied. Two of the patients also received treatment with other antirresortive and osteoformating treatments. The median age was 75 years (IQR=20). The most used biphosphonate was Alendronate, beeing in the 66,6% of the patients the first treatment. The median time of expotion to biphosphonates was 8,5 years (IQR=3). In the 83,3% of the patients the fracture was situated in the medial third of the femoral diaphisis.
Conclusions In our study the prevalence of atypical fractures with biphosphonates was low, a 0,6% of all of the fractures studied.
Disclosure of Interest None declared