Atypical femoral fractures (AFFs) are reported in patients taking bisphosphonates (BPs). This study aims to describe demographics, potential risk factors and outcome of fixation in AFFs.

Forty-three patients with AFF were identified retrospectivity from all identified patients with subtrochanteric or diaphyseal fractures within NHS Grampian between 2008–2018. Patients were identified via hospital coding and electronic search of patients undergoing femoral fixation. AFFs were diagnosed by the 2014 American Society of Mineral and Bone Research diagnostic criteria by electronic patient record review by two investigators.

Within this cohort, the incidence of AFF was 8.25% with male to female ratio of 10:1 and a mean of presentation age 73.3 years. 27.9% of AFFs occurred in the diaphysis. 22% of AFFs were bilateral. Mean follow-up was 11.5 months. 87.5% of patients had documented prodromal symptoms. 35% had proven radiological changes before fracture. All patients identified were on BPs. Duration of BPs before fracture was 5 months- 13.2 years (mean 6.3 years). Concurrent use of BPs with steroid and proton pump inhibitors was seen in 58.5%. All patients had intramedullary fixation with 8 (18.6%) requiring revision for non-union. For those that united radiologically it took on average 304 days (220–513). BPs were only stopped in 45% of patients after fixation.

AFFs in this cohort appear to be associated with BP use, female sex, clinical and radiological prodrome. AFF remain a difficult clinical problem with a high revision rate. Further work is required to identify the temporal relationships and to raise awareness to improve surveillance/management.