Author Affiliations: Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota.
Osteoporotic fractures have generally been defined as fractures that occur following relatively low trauma, such as a fall from standing height or less.1 Implicit in this definition is the assumption that this type of skeletal trauma would not result in fracture of a normal bone, since the strength of the bone should be able to withstand such force. A surrogate marker for bone strength now used and considered the current gold standard for diagnosing osteoporosis prior to the occurrence of a fracture is calculation of areal bone mineral density (BMD) by dual-energy x-ray absorptiometry. This technique measures the amount of mineral in bone (in grams), typically at the lumbar spine, proximal femur, or distal forearm, and divides this amount by the projected area of the bone, providing a density expressed in grams per centimeter squared. Low BMD is a robust predictor of osteoporotic fracture risk2; conversely, low-trauma fractures are related to BMD.3
Khosla S. High-Trauma Fractures and Bone Mineral Density. JAMA. 2007;298(20):2418–2419. doi:10.1001/jama.298.20.2418