The main purpose of this study is to assess whether a locally-administered rhBMP-2/CPM injection can rapidly increase bone mass in subjects at high risk for osteoporotic fractures of the hip. All subjects will receive standard treatment for low bone mass, consisting of bisphosphonates, calcium, and vitamin D (all taken by mouth). Subjects that are randomly selected to receive treatment with rhBMP-2 will receive an injection directly into the hip. The injection is given in a surgery room using a light anesthesia.