 Osteoporosis is a systemic bone disease characterized by low bone mass and microarchitectural deterioration of bone tissue with consequent bone fragility and susceptibility to fracture. Fifty percent of women and 20 men older than 50 y.o. will have an osteoporotic fracture fragility fracture. Fragility fracture is defined as one that results from a low-energy trauma such as a fall from body height. A previous fracture is an important predictor of a new fracture, especially in the first 5 years after initial fracture. A second fracture can be particularly devastating if it is a hip fracture. Low bone mineral density, measured by bone densitometry, as well as a previous osteoporotic fracture, are the two major risk factors for the occurrence of a new fracture. 