Can Osteoporosis Drugs Weaken Bone?

The Journal of Orthopaedic Trauma  (May/June 2008, Volume 22, Issue 5) published a retrospective review was of patients with femoral shaft fractures admitted to a Level 1 trauma center between January 2002 and March 2007. Seventy low-energy fractures were identified. These are leg fractures (thigh) that occurred with little or no trauma.
The researchers looked at 59 females and 11 males, averaging 74.7 years of age. Twenty-five (36%) were being treated with alendronate (a biophosphonate, which is an osteoporosis drug) Nineteen (76%) of these 25 patients  had a fractured femur (thigh bone). The fracture was demonstrated a simple, transverse fracture with a unicortical beak in an area of cortical hypertrophy. This fracture pattern was seen in only one patient (2%) not being treated with alendronate.
Bone is living tissue. It is continually breaking down and rebuilding. In many women over 30, bone resorption occurs faster than rebuilding. Biophosphonates, like Fosamax, Actonel and Boniva are designed to slow this process down. There is some evidence that microscopic fractures that occur normally in bone are not repaired when these drugs suppress the remodeling process. Another problem that can occur with these drugs is osteonecrosis, which is a painful condition where the bone literally dies and rots.