A probable atypical ulnar fracture in a man receiving denosumab

Atypical femur fractures are widely recognized and associated with anti-resorptive therapy, most commonly bisphosphonates. These fractures generally occur in the femoral shaft or subtrochanteric region. Cases of atypical fractures at non-femur sites, including the ulna, have been reported. Here we report a probable atypical ulnar fracture in a man receiving denosumab, who had been using his upper extremities for transfers and ambulation. Radiographs demonstrated a non-comminuted, transverse fracture somewhat similar to findings of atypical femur fractures. He was deemed a poor surgical candidate and treated with teriparatide. To our knowledge, this is the first reported probable atypical ulnar fracture potentially associated with denosumab use. We believe it important that clinicians be aware of the association of anti-resorptive therapy with atypical fractures not only of the femur, but also at other skeletal sites. In patients on long-term anti-resorptive therapy, it is appropriate to consider that persistent “prodromal” pain might indicate an impending atypical fracture at an atypical skeletal site.