Atypical stress femoral shaft fracture secondary to alendronate therapy

Abstract

Bisphosphonate (BP) therapy is widely used as it remains the first-line of treatment for osteoporosis. These antiresorptive drugs inhibit osteoclast function and promote apoptosis. However, atypical stress femoral fractures occurring in the diaphysis and subtrochanteric region are linked to prolonged BP use. The risk of fracture is directly proportional to the time exposed to the treatment. Ongoing BP exposure prevents bone resorption and replacement in areas with accumulated microdamage through targeted remodeling. Therefore, long-term BP use (more than 5 years) is an important risk factor. Atypical femoral fractures remain very rare, and the benefits of BP therapy for osteoporotic fracture prevention and treatment outweigh the risk. The present report consists of a rare case of a patient with an atypical diaphyseal femoral stress fracture secondary to prolonged alendronate use.