Atypical Femur Fractures From Bisphosphonates?

Broken bones may occur as a result of medication prescribed to strengthen them.

Synopsis

RESEARCH According to two reports presented at the American Academy of Orthopaedic Surgeons (AAOS), long-term use of bisphosphonated drugs such as Actonel, Boniva, Fosamax, and Reclast increases the risk for atypical subtrochanteric femur fractures. These drugs are most often prescribed to strengthen the bones of patients with osteoporosis. The FDA has disregarded the recent reports, stating there is no clear connection based on available evidence between bisphosphonates... and atypical femur fractures.

The MedWatch system, run by the FDA, collects clinical reports about potential side effects of approved drugs. Multiple reports of the same side effects trigger additional investigation. With this in mind, MedWatch has recorded other potential side effects of bisphosphonate, including jaw deterioration and esophageal cancer.

Fosamax was the first of its class of drugs approved in 1995. Orthopedic surgeons across the country (U.S.) are noticing fractures straight across the thigh bone below the hip rather than within the joint among patients who have been taking the drug for five or more years.

In one of two reports recently submitted to AAOS, a research team led by Dr. Joseph Lane at New York's Hospital for Special Surgery did bone biopsies and found qualitative differences in bone that might explain the atypical fractures. A second study, by a group at New York Presbyterian Hospital, used sophisticated bone density scans and found that bisphosphonate drugs initially increased structural integrity of the femur but that the effect tapered off over four years of treatment.

To better address the question, scientists would need to conduct a large-scale study following tens of thousands of patients for at least five years — a very expensive and unlikely prospect.

Current estimates put the rate of atypical fractures at fewer than 1 in 10,000 patients who take bisphosphonates, according to the American Society for Bone and Mineral Research, a specialist group of scientists and doctors.

Tags: anomaly, human, orthopedic, orthopaedic, pharmaceutical, radiology, x-ray

Reference

See 2010 LA Times article for more details.