Karen Armstrong’s case began with a routine laparoscopic surgery in 2010, performed by Dr. Colin Ward. The procedure took an unexpected turn when Armstrong suffered severe complications, including the removal of her left kidney, due to damage to her ureter during the operation. She alleged that Dr. Ward’s improper use of a medical device, the LigaSure, had caused the injury by being too close to the ureter—just 1-2 millimeters away.
The trial court initially ruled in Armstrong’s favor, finding Dr. Ward liable for breaching the standard of care. However, the Ontario Court of Appeal overturned this decision, arguing that the trial judge had incorrectly focused on the injury’s outcome rather than the surgeon’s actions. Justice Katherine van Rensburg’s dissenting opinion stood out, as she emphasized that the trial judge had correctly assessed the standard of care based on the evidence presented.
The Supreme Court’s decision to reinstate the trial court’s ruling marked a pivotal moment. The Court clarified that causation—the question of what caused the injury—could be addressed before determining whether the standard of care was breached. This approach simplifies the process for plaintiffs, allowing them to present a clearer case for liability.
The ruling also reinforced the role of circumstantial evidence in proving negligence. The Court agreed that the nature and severity of Armstrong’s injury could serve as evidence of a breach of care, particularly when non-negligent causes were ruled out. This principle is especially significant in medical cases, where plaintiffs may lack direct insight into the procedures performed.
By addressing these issues, Armstrong v. Ward has set a new standard for medical malpractice litigation in Canada. The decision not only strengthens the position of plaintiffs but also ensures greater accountability for medical professionals. Its implications continue to ripple through the legal landscape, influencing how courts approach negligence cases and interpret the standard of care.
Another important principle is the role of circumstantial evidence in determining whether the standard of care was breached. The Court emphasized that the nature and severity of an injury can serve as evidence of negligence, particularly when non-negligent causes have been ruled out. For example, in Armstrong’s case, the injury to her ureter was deemed so severe that it implied a breach of the standard of care, as no reasonably competent surgeon would have used the LigaSure device within 1-2 mm of the ureter.
The ruling also rejected the notion that medical professionals could defend against negligence claims by merely demonstrating an intention to follow proper procedures. The Court made it clear that the actual execution of these steps is necessary to meet the standard of care. This principle ensures that medical professionals are held to the same liability standards as defendants in other negligence cases, preventing exceptions that could unfairly shield them from accountability.
Furthermore, the decision effectively revived the evidentiary doctrine of res ipsa loquitur, which allows an injury to “speak for itself” as evidence of negligence. This doctrine is particularly relevant in medical cases, where plaintiffs may lack direct insight into the procedures performed during surgery. By reviving this principle, the Court has provided an additional tool for plaintiffs to prove negligence in cases where the injury itself suggests that something went wrong.
The implications of the Armstrong v. Ward decision are far-reaching. Plaintiffs in medical malpractice cases now find it easier to argue negligence, as the burden of proof has been somewhat alleviated by the Court’s rulings on causation and circumstantial evidence. The decision has already influenced subsequent cases, such as Szeto v. Kives and Dallner v. Gladwell, where trial judges have relied on Armstrong to address causation before determining whether the standard of care was breached.
Overall, the Armstrong v. Ward decision has brought greater consistency to medical malpractice litigation, ensuring that medical professionals are held accountable for failing to meet the required standard of care. By clarifying these legal principles, the Supreme Court has strengthened the position of plaintiffs and ensured a more equitable approach to negligence cases in the medical field.

Conclusion
The Supreme Court of Canada’s decision in Armstrong v. Ward has significantly reshaped the landscape of medical malpractice litigation. By clarifying that causation can be addressed before assessing the standard of care and emphasizing the role of circumstantial evidence, the Court has made it easier for plaintiffs to prove negligence. The ruling has also revived the doctrine of res ipsa loquitur, allowing injuries to “speak for themselves” in certain cases. This decision not only strengthens the position of plaintiffs but also ensures greater accountability for medical professionals, setting a new standard for negligence cases in Canada. Its influence is evident in subsequent cases, demonstrating its far-reaching impact on medical malpractice law.
Frequently Asked Questions
- What was the Armstrong v. Ward case about?
- The case involved Karen Armstrong, who suffered severe complications during surgery, including the removal of her left kidney, due to the improper use of a medical device. The Supreme Court of Canada ruled that the surgeon breached the standard of care, simplifying the process for plaintiffs to prove negligence.
- What legal principles were established in Armstrong v. Ward?
- The decision established that causation can be addressed before assessing the standard of care and highlighted the role of circumstantial evidence in proving negligence. It also revived the doctrine of res ipsa loquitur, allowing injuries to serve as evidence of negligence.
- How does the Armstrong v. Ward decision affect medical malpractice cases?
- The decision makes it easier for plaintiffs to argue negligence by allowing causation to be addressed first and by using circumstantial evidence. It ensures medical professionals are held accountable, aligning their liability standards with other negligence cases.
- What is res ipsa loquitur and how does it apply here?
- Res ipsa loquitur is a doctrine allowing an injury to “speak for itself” as evidence of negligence. In this case, the severity of Armstrong’s injury implied a breach of care, as no competent surgeon would have used the device so close to the ureter.
- How has Armstrong v. Ward influenced other legal decisions?
- The decision has influenced cases like Szeto v. Kives and Dallner v. Gladwell, where courts have applied its principles to address causation before assessing the standard of care, ensuring consistency in medical malpractice litigation.