Retrospective review of patients with atypical bisphosphonate related proximal femoral fractures.

Introduction: Patients may be at an increased risk of atypical proximal femoral fractures with prolonged bisphosphonate use.

Patients And Methods: This was a retrospective review of patients who sustained a subtrochanteric fracture of the femur in our department between April 2009 and March 2014. The radiographs were reviewed for features of atypical femoral fractures as described by the American Society of Bone Mineral Research.

Results: 185 patients were coded according to the National Hip Fracture Database as having sustained a subtrochanteric fracture of the femur. Of these, 26 patients had radiographic findings consistent with an atypical subtrochanteric fracture. 5 patients were excluded as their histology confirmed malignancy. 12 patients were taking bisphosphonates on admission. All 12 patients were females taking alendronic acid on admission, who sustained the fracture as the result of minimal or no trauma and underwent long gamma nail fixation. The mean age was 71.6 years (range 62-79 years). The mean length of time on bisphosphonates prior to admission was 8.33 years (range 3-25 years). 9/12 patients had pre-existing symptoms for between 5days and 2 years prior to admission. 1 patient sustained a broken gamma nail 14 weeks post-operatively requiring revision. The mean time to discharge from theatre was 16days (range 5-57days). The mean time to radiological union in the patients in whom there was evidence was 24 weeks.

Conclusions: In this small group of patients, management of this fracture pattern can be complex with the potential for delayed or non-union and prodromal symptoms are common.