Could an ortho consultant surgeon know from x rays or ct if patient with a fracture had osteoporosis?

Yes: The x ray could show significant demineralization that could lead the radiologist or orthopedic surgeon to suggest osteoporosis . However confirmatory bone mineral density scan with a T-score of less than -2.5 per who standard is required to confirm the diagnosis.

Maybe: You can take an educated guess based on bone structure on the plain films and ct.