Objective: Previous studies reported that prolonged alendronate use was related to insufficiency fractures. Fewer reports presented this phenomenon in patients with risedronate use. The present study reported on two patients, both of whom had long-term use of alendronate and risedronate then sustained subtrochanteric femoral insufficiency fractures with minimal trauma.
Case summary: One of the patients was treated with alendronate therapy in concern of her risk factors for osteoporosis (her previous a hysterectomy with bilateral oophorectomy) with unsubstantiated evidence of her pretreatment, bone-mineral-density measurements (BMD), for a 10-year prior episode of left prodromal thigh pain and an insufficiency fracture at 8 days post experiencing the pain. The other patient had a history of the hysterectomy and right salpingo-oophorectomy, a low-energy metatarsal fracture with resulting osteopenia verified with BMD measurements. She was treated with alendronate for 42 months before switching to risedronate for 6 months per patient's request but no history of prodromal thigh pain. Subsequently, she sustained an insufficiency fracture, while standing and turning her body. Both patients had the significant long-term uses of bisphosphonate and exhibited the typical radiographic characteristics of insufficiency fracture. From the present report, risedronate is another prospective medication that might be related to insufficiency fractures.
Conclusion: The present study concluded that cautious consideration is essential for long-term alendronate and risedronate use for any individual patient. The index of suspicion for the subtrochanteric femoral insufficiency fracture should be higher in the patients presenting with prodromal thigh pain. Further studies are necessary to identify the class effect of other bisphosphonate drugs, the definitive mechanisms between all generations of bisphosphonate treatments and their complications, including the individual risk factors of the insufficiency fracture.