A case of atypical femur fracture during long-term treatment with bisphosphonates in patient with postmenopausal osteoporosis

Bisphosphonates is a first-line therapy for treatment of osteoporosis. In the last decade, the number of atypical femur fracture (AFF) cases during long-term treatment with bisphosphonates has increased. The aim of this article was to analyze the literature data on this problem, to define the diagnostic criteria of AFF and to present the case of AFF in the patient who received treatment with alendronate for 3.5 years. A 78-year-old woman, receiving oral bisphosphonate for severe postmenopausal osteoporosis for 3.5 years, suddenly started feeling pain in her right thigh while walking. Three months later, she had got a fracture in middle third of the right femur after falling from her standing height. According to instrumental diagnostics, this fracture had all criteria of AFF. Blocking intramedullary osteosynthesis with shafts was performed. A retrospective analysis of soft tissue magnetic resonance imaging in the area of right thigh, done before the fracture, showed the presence of undiagnosed incomplete right femur fracture in the middle third, which subsequently led to a complete fracture. Presented clinical case demonstrates the complexity of AFF diagnostics. The purpose of the publication is to draw attention of medical specialists to the issue of this rare side effect of bisphosphonate treatment.