Rosenberg v Percival

The High Court of Australia considered an appeal by a surgeon, Dr. Rosenberg, against a decision of the Full Court of the Supreme Court of Western Australia. The case concerned a claim in negligence brought by a patient, Ms. Percival, who alleged that the surgeon had failed to adequately warn her of a material risk associated with a surgical procedure. The dispute centred on whether the surgeon had breached his duty of care and, if so, whether that breach had caused Ms. Percival's injury.

The legal issues before the High Court included the test for identifying a "material risk" in the context of a surgeon's duty to warn, and the principles governing causation in such cases. Specifically, the court had to determine whether a patient's failure to undergo treatment, if properly warned, was causative of their injury. The High Court also considered the powers of an appellate court when reviewing a trial judge's findings of fact, particularly those based on the credibility of witnesses, and the extent to which an appellate court could substitute its own conclusions.

The High Court acknowledged that the trial judge had erred in his assessment of certain evidence regarding the condition of the patient's garden, but found this error did not decisively impact the overall assessment of the patient's credibility. The court affirmed that Australian law applies a subjective test to determine whether a patient would have refused a medical procedure if warned of a material risk. This means that if the patient's testimony regarding their hypothetical decision is believed, they will succeed, even if objective facts suggest otherwise. Conversely, if the patient's direct testimony is rejected, they bear a significant evidentiary burden to prove causation based on objective facts and probabilities. The court noted that determining what a patient "would have done" in a hypothetical scenario requires an anterior finding as to what they "would have decided" if properly warned, with the onus on the patient to prove this hypothetical decision.

The High Court allowed the appeal, setting aside the orders of the Full Court of the Supreme Court of Western Australia and dismissing the appeal to that court. The respondent, Ms. Percival, was ordered to pay the costs of the appeal to the High Court and the costs incurred before the Full Court of the Supreme Court of Western Australia.