Atraumatic intracapsular neck of femur fractures after prolonged bisphosphonate treatment: a new atypical variant?

We present 2 cases of elderly females presenting with atraumatic, near-vertical (Pauwells grade 3), intracapsular neck of femur fractures. Following diagnosis of osteoporosis on DEXA scans, they had received alendronic acid for 7 and 10 years respectively. Routine blood tests and serum estimations of calcium, vitamin-D and thyroid-stimulating hormone, done at admission, were within the normal ranges. These patients were managed with a hemiarthroplasty and a dynamic hip screw (DHS) respectively, following discontinuation of bisphosphonates. We present these 2 cases in light of emerging evidence that associates long-term bisphosphonate use with atypical low energy femoral fractures. Only subtrochanteric/diaphyseal fractures have been reported to date. We present a new variant of atypical femoral neck fractures in metaphyseal bone related to prolonged bisphosphonate therapy.