Court of appeal rejects “loss of chance” as basis for causation

Date Closed

May 22, 2013

Lead Office


The Plaintiff developed septic arthritis in his knee, further to a reconstructive surgery of his anterior cruciate ligament. He claimed that his condition had suffered from late diagnosis and treatment.

In 2010, after a two-month long trial, the Superior Court of Quebec ruled against the orthopaedic surgeon for not having provided adequate care in relation to symptoms that were considered sufficient to indicate septic arthritis and to warrant intervention. In the context of a delay in treatment of about 48 hours, the Superior Court chose to rely on a presumption of causation in favour of the Plaintiff. The court calculated that he had been deprived of a treatment in the first few hours after the emergence of the symptoms and had to be compensated for 42% of his damages.

On May 22, 2013, the Court of Appeal allowed in part the appeal of the orthopaedic surgeon, and dismissed the Plaintiff’s claim against him. According to the decision written by Justice Benoit Morin, the Court of Appeal concluded that the Superior Court had committed a significant legal error by drawing an inference of causation. After restating that the Plaintiff must prove causation following the same burden in a case of medical liability as in any civil liability cases, i.e. on a balance of probabilities, the Court of Appeal confirmed that the causation analysis is the same for any type of fault, regardless of whether it manifested itself through action or omission.

The Court of Appeal concluded that it was incorrect to infer a presumption of causation worth 42% of the damages claimed by the Plaintiff on the basis of the delay of intervention, as this would amount to sanctioning a “loss of a chance”, inadmissible under Quebec law.

The action of Plaintiff against the orthopaedic surgeon is dismissed without costs.

McCarthy Tétrault represented the defendant with a team that was led by Robert-Jean Chenier.