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Moore v. Getahun, 2015 ONCA 55

This case considers the preparation and use of expert evidence in the context of a medical malpractice lawsuit. This case is relevant for family law proceedings because expert evidence is frequently called upon and relied on for property, child custody and access, and support claims.


Following a motorcycle accident, the respondent (plaintiff) was treated by an orthopedic surgeon, the appellant (defendant), for a broken wrist. The appellant put the respondent’s forearm and wrist in a full cast. The respondent suffered permanent damage to his muscles due to compartment syndrome, “a painful condition resulting from the expansion of enclosed tissue within its anatomical enclosure producing pressure that interferes with circulation and adversely affects the function and health tissue of itself.” The respondent’s position was that the appellant was negligent in the application of the cast, causing the compartment syndrome.

At trial, there was conflicting expert evidence. The medical expert for the respondent testified that, in his opinion, the full cast had caused the compartment syndrome and that a half cast or splint should have been used. It was the opinion of two medical experts called by the appellant that the compartment syndrome was caused by the original injury itself and that a full cast was the appropriate treatment.

Counsel for both parties called viva voce evidence (oral testimony) from the experts and did not submit the experts’ written reports as exhibits. However, counsel did provide the expert reports to the judge as an aide memoire to help the judge understand and follow the experts’ technical evidence.

The judge took issue with one of the expert reports because it had been revised after the expert consulted with counsel. The judge criticized the appellant’s counsel for discussing the content of the report with his witness and demanded to see the expert’s original draft. The judge ultimately relied on these reports in her reasons and found in favour of the respondent.

The issues for the Ontario Court of Appeal were whether the trial judge committed legal errors in her analysis and, if so, whether a new trial should be ordered.


It is the duty of an expert witness to provide opinion evidence that is fair, objective and non-partisan. The trial judge strongly disapproved of the practice of counsel reviewing draft expert reports and stated that this practice undermines the expert’s credibility and neutrality. However, it is widely accepted in the legal profession that consultations between counsel and expert witnesses in the preparation of reports is permissible and “within certain limits, is necessary to ensure the efficient and orderly presentation of expert evidence and the timely, affordable and just resolution of claims” (paragraph 49). It is appropriate for counsel to review draft expert reports to ensure that the reports comply with the Rules of Civil Procedure and the rules of evidence, do not go beyond the scope of the case, and are clear and comprehensible. If there is an air of reality that counsel has improperly influenced an expert witness, this would likely be revealed in cross-examination. A judge may then reject or limit the weight to be given to the expert evidence if there is evidence of a lack of independence or impartiality. The Court found that neither the counsel nor the expert acted improperly and the report reflected the expert’s genuine and unbiased opinion.

The trial judge had ordered the expert to provide his original draft report. The Court of Appeal found that this was improper because the draft report was covered by litigation privilege. “Absent a factual foundation to support a reasonable suspicion that counsel improperly influenced the expert, a party should not be allowed to demand production of draft reports or notes of interactions between counsel and an expert witness … The trial judge erred in law by stating all changes in the reports of an expert witness should be routinely documented and disclosed” (paragraph 78).

The trial judge also used the expert reports to contradict the experts’ viva voce evidence. This was an error in law because the reports were provided to the judge only as an aide memoire and not as evidence. Since the reports were not the proper subject of cross-examination, the experts were not given the opportunity to explain the inconsistencies between the reports and their oral evidence. As a matter of trial fairness, the trial judge erred because the reports were not exhibits and the perceived contradictions were not put to the experts in cross-examination.

The Court of Appeal concluded that the trial judge had made certain errors in her analysis and use of the expert evidence. However, these errors were not a significant factor in the judge’s determination that the full cast caused the respondent to suffer compartment syndrome. There were several other reasons to prefer the expert evidence for the respondent, including the fact that he had more experience as an upper extremity orthopedic surgeon than the appellant’s experts did. The Court found that the errors made by the trial judge did not give rise to a substantial wrong or miscarriage of justice. Therefore, the Court did not order a new trial and dismissed the appeal.