Rufo v Hosking

The case of *Rufo v Hosking* concerned a claim for medical negligence brought by the appellant against a specialist paediatrician. The appellant alleged that the paediatrician's treatment for Lupus, which involved high-dosage corticosteroids, led to spinal microfractures. The dispute centred on whether the paediatrician's actions caused the appellant to lose a chance of avoiding these injuries. The matter was heard in the Court of Appeal of New South Wales.

The primary legal issues before the Court of Appeal were whether the paediatrician had breached their duty of care and, if so, whether that breach caused the appellant to suffer a loss of a chance of avoiding the spinal microfractures. Specifically, the court had to consider whether the paediatrician's substitution of one corticosteroid for another, resulting in a heavier dosage, and the failure to introduce a steroid-sparing agent at the appropriate time, constituted negligence. Furthermore, the court had to determine the recoverability of a less than 50% chance of avoiding the injuries, and whether the "all or nothing" approach to causation and damages was appropriate in this context. The court also considered the relevance of expert evidence and the difficulty in quantifying a lost chance, noting that such a chance must be material and not speculative.

The Court of Appeal reasoned that while it was more probable than not that the microfractures would have occurred even without the breaches of duty, the appellant had nevertheless lost a material chance that, but for the negligence, the fractures would not have occurred, or would have occurred at a different time or with less severity. The court found the UK *Fairchild* approach to causation inapplicable to this situation. The court observed on the permissibility of a loss of chance approach in medical negligence cases, provided the chance is material.

The appeal was allowed with costs.