Atypical Fracture of Femur: Likely Related to Long-term Bisphosphonate Use.

ABSTRACT

Bisphosphonates are widely prescribed and highly effective at limiting the bone loss that occurs in many disorders characterized by increased osteoclast-mediated bone resorption, including senile osteoporosis in both men and women. Although, they are generally well-tolerated, potential adverse effects may limit bisphosphonate use in some patients. Optimal use of bisphosphonates for osteoporosis requires adequate calcium and vitamin D intake before and during therapy. Long-term adverse effects of bisphosphonate therapy include osteonecrosis of the jaw and atypical fractures of femur. We report a case of a 78-year-old man who presented with pain and inability to move the left thigh from 11 am on the day of admission. He was diagnosed to have transverse subtrochanteric fracture of the left femur with relatively thick cortex. He had been religiously taking alendronate (a bisphosphonates) 70 mg once a week along with calcium preparation (elemental calcium 500 mg with cholecalciferol 250 units twice-daily) for 5 years. With this background of a ‘chalk stick’ like transverse fracture of the subtrochanteric region of femur in an otherwise healthy elderly man, an ‘atypical fracture of femur’ from long-term use of bishphosphonates was the likely cause.