Insufficiency fractures related to low-dose adefovir dipivoxil treatment for chronic hepatitis B.

We present a case of a 53-year-old woman who developed multifocal insufficiency fractures associated with adefovir dipivoxil (ADV) induced osteomalacia, including recurring metatarsal insufficiency fractures and a subtrochanteric femoral insufficiency fracture requiring surgical fixation. She had received low-dose ADV treatment for 59 months for chronic hepatitis B viral infection at the time of presentation with subtrochanteric fracture. Imaging evidence of multifocal insufficiency fractures and metabolic disease on background of hypophosphatemia is attributed to hypophosphatemic osteomalacia from adefovir-induced renal proximal tubular dysfunction. Radiologists and clinicians should be aware of the possibility of insufficiency fractures in patients receiving ADV therapy to avoid delayed diagnosis and progression of high-risk proximal femoral fractures.