Background: Bisphosphonates are widely used in patients with osteoporosis to reduce bone loss and prevent fractures, however atypical femoral fractures remain a rare but significant complication of treatment. This study aims to identify risk factors for the development of atypical femoral fractures and detect those patients who may be at higher risk of developing bilateral fractures.
Methods: We conducted a retrospective review of cases of atypical femoral fractures presenting to two metropolitan hospitals over an 8 year period between 2011-2018. All fractures were confirmed by a radiologist and an orthopaedic surgeon using the American Society for Bone and Mineral Research Task Force 2013 revised case definition of atypical femoral fractures1.
Results: 27 patients presented with atypical femoral fractures during the study period. There were 23 females and 4 males with a mean age of 77 years. 20 patients had unilateral atypical femoral fractures, and 7 had bilateral atypical femoral fractures or unilateral atypical femoral fracture with impending fracture on the contralateral side. Bisphosphonates were the largest risk factor for the development of an atypical femoral fracture with 23 patients having had prior exposure. Other identified risk factors included Asian ethnicity (9 patients), glucocorticoid exposure (8 patients) and underlying rheumatoid arthritis (4 patients). A significant proportion of patients with atypical femoral fractures were inappropriately prescribed bisphosphonate therapy.
Conclusion: Bisphosphonate therapy is not without risk, and there needs to be close monitoring and prompt screening for atypical femoral fractures in those with risk factors or prodromal symptoms. There needs to be judicious use of bisphosphonate therapy in patients with osteoporosis and ongoing review of the necessity of treatment in patients in order to prevent unnecessary complications.