Journal of Osteoporosis and Physical Activity
Open Access

Abstract

Atypical Femoral Fractures: Pearls and Pitfalls

Eduardo Frois Temponi, Lúcio Honório de Carvalho Júnior and André Gomes Ribeiro

Recently much attention has been given to the possible relationship between the use of bisphosphonates and some low-energy femoral fractures. These fractures were named “atypical fractures” to distinguish them from “typical fractures” that occur in the neck and trochanteric region of low energy trauma in the elderly and in the femoral shaft. Atypical fractures are stress fractures that occur in the femur (subtrochanteric or diaphyseal region) and are closely related to chronic use of bisphosphonates. Although the pathogenesis of atypical fracture of the femur remains unclear, several pathological mechanisms have been proposed. It is believed that prolonged use of bisphosphonates decrease osteoclast activity by reducing bone’s ability to remodel and leading to an accumulation of micro damage with reduced bone strength. There is a prodrome period of pain before the fracture is complete. The patients using bisphosphonates should be advised about the appearance of symptoms that might indicate a possible atypical femoral fracture. The emergence of pain in the groin or thigh should be investigated. Conventional radiography is usually the initial imaging procedure, followed by magnetic resonance imaging (MRI), computed tomography (CT) or bone scan. Symptomatic patients with an incomplete fracture can be treated conservatively or can have a prophylactic fixation indicated. For patients with atypical fractures or a stress reaction, the bisphosphonates must be stopped and adequate supplementation of calcium and vitamin D should be started. Alternatively, the use of parathyroid hormone (PTH) or others bone anabolic agents can be used in some cases.