Came across an interesting article via Medscape on atypical (subtrochanteric) femoral fractures in patients using bisphosphonates. It reviews a Swiss case control study of 477 patients aged 50 and over with hip fractures followed from 1999 to 2010 (11 years). Below are my take home messages:
- Bisphosphonates are associated with a significant increase in the risk of an atypical fracture v classical, Odds Ratio (OR) of 69.
- The longer bisphosphonates are used the higher the OR of atypical:classical fracture: 35 at 2y to 175 at 9y.
- Long term bisphosphonate use results in “frozen bone” i.e. a decrease in the rate of bone turnover.
- Bilateral fractures have an Odds Ratio of x42 in atypical cases compared to classic cases.
- X-raying both legs is thus a sensible practice if an atypical fracture is noted or suspected.
- We should be considering stopping bisphosphonates in low risk individuals after 3-5 years of therapy. A medication ‘holiday’.