Is avascular necrosis a material risk to the continued use of prednisone?

Even though avascular necrosis represented a risk that was a "mere possibility which ordinarily need not be disclosed", yet, if its occurrence caused serious consequences such as bone failure, it was a material risk to the continued use of prednisone and should have been disclosed to the plaintiff. The materiality of the risk resulting from the intake of large doses of prednisone over a lengthly period of time is partly a matter of medical judgment but ultimately a matter for me to decide as the trier of fact: Reibl v. Hughes, 1980 CanLII 23 (SCC), [1980] 2 S.C.R. 880, 14 C.C.L.T. 1, 114 D.L.R. (3d) 1 at 5 and 13, 33 N.R. 361. At p. 5: It is now undoubted that the relationship between surgeon and patient gives rise to a duty of the surgeon to make disclosure to the patient of what I would call all material risks attending the surgery which is recommended… …even if a certain risk is a mere possibility which ordinarily need not be disclosed, yet if its occurrence carries serious consequences, as for example, paralysis or even death, it should be regarded as a material risk requiring disclosure. And at p. 13: "The materiality of non-disclosure of certain risks to an informed decision is a matter for the trier of fact …"