Is vitamin K2 a treatment choice for atypical femoral fractures in patients with secondary osteoporosis?

An atypical femoral fracture (AFF) is a rare complication associated with excessive inhibition of osteoclast expression during treatment of osteoporosis. We herein describe a patient who had been treated with alendronate for more than 10 years and subsequently developed an AFF that healed after treatment with vitamin K2 (VK2). We also discuss the potential beneficial effects of VK2 on the healing of AFFs. A 48-year-old Asian man with secondary osteoporosis was treated with alendronate for more than 10 years. The patient underwent surgical treatment for a complete AFF of the right femur. Six months postoperatively, he complained of pain in his left thigh. X-ray examination revealed an incomplete AFF of the left femoral shaft. He was then treated with VK2. After 4 months of VK2 treatment, the patient reported that the pain in his left thigh had decreased, and follow-up X-ray examination demonstrated healing of the left AFF line. This case report indicates that VK2 may be a potential direction for pharmacological treatment of AFFs in future research.