This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
A 70 years old female is on treatment withAlendronate for 7 years for osteoporosis. Now she complains of pain in right thigh'at is the next investigation to be performed? 
Select and explain. 
A. DEXA scan, B. X-ray, C. Serum vitamin D levels, D. Serum alkaline phosphate levels
B: X-ray
Answer: B: X-ray 
Explanation: Ans. b. X-ray The pain in right thigh in a 70 years old female, who is on treatment with alendronate for 7 years for osteoporosis might be due to femoral shaft fracture. Plain X-rays showed a characteristic picture consisting of a transverse or sho oblique fracture line, lateral coical thickening, and medial spiking. Spontaneous femoral shaft fracture after long-term alendronate: Alendronate is used as first-line treatment for osteoporosis in postmenopausal women worldwide. The evidence suppoing its benefit in reducing the risk of fragility fracture among this high-risk group is well established. Due to its mechanism of action, there were concerns about potential reduction in bone turnover, repair of microdamage and hence reduced bone toughness and increased risk of fractures with long-term use. Plain X-rays: Plain X-rays showed a characteristic picture consisting of a transverse or sho oblique fracture line, lateral coical thickening, and medial spiking.