Objective: Atypical femoral fractures (AFF) are attracting attention as they are caused by the treatment for osteoporosis. Unfortunately, the number of reports is increasing. We examined the cases in our hospital in whom were surgically treated and determined any associated characteristics.

Methods: There were seven patients (10 lower limbs) with AFF who underwent surgical treatment in March 2016 to July 2018, inclusive.

Results: The average age was 70.8 years (range: 49-88 years old) , and all cases were female. There were 5 complete fractures, 2 incomplete fractures, and 3 bilateral fractures. Surgery (prophylactic intra medullart nail) was performed for incomplete fractures. In all subjects there were no mechanical injuries or low energy impacts. In six of seven patients, bisphosphonate (BP) treatment was being administered. In the remaining one patient, denosumab was used. The average period of oral administration of BP was 5.6 years. The average bone fusion period of patients with complete fractures was 8.7 months.

Conclusion: A close relationship between AFF and BP was suggested by this small case series. The bone union period was prolonged in cases associated with AFF.