My mother was diagnosed with postmenopausal osteoporosis of the spine several years ago and was prescribed Fosamax. She was on the medication for 12 years and it was just recently discontinued when she changed health care providers. In the last two years, she has had 3 spontaneous rib fractures at 6th-8th rib level, posterior, two on one side and one on the other. She is now being told that her bones are very brittle and she is at high risk for continuing fractures. These are very painful and debilitating. Why is she getting these fractures when the medication was supposed to prevent them?