Meniscus removal in knee surgery can cause major cell death after just hours of exercise: study

Researchers at the University of Calgary have put a formerly common knee surgery practice under the microscope to find how it can cause osteoarthritis.

For years, if a patient tore their meniscus in their knee it was common practice to remove part of — or all of it. Doctors have since realized it caused degeneration and now try to focus on repair rather than removal, but they weren't exactly sure why.

But now scientists have discovered what problems that removal causes — and just how fast it happens.

"Taking out the meniscus on its own was associated, when the joint was loaded, with an enormous amount of cell death," said Dr. Walter Herzog, head of the university's human performance laboratory and one of the authors of the study published in Nature, Scientific Reports.

"You load your joint relatively vigorously then cells will die and then you have dead cells in your articular cartilage. That's obviously not good for the health of the cartilage."

Researchers used a powerful microscope to study cells in the knees of mice, some of which had their meniscus removed and were then subjected to muscle stimulation to simulate running while under anesthesia.

Watching the cell degradation in real time, the researchers saw when the meniscus was removed, half of the cells which maintain knee cartilage were dead within four hours.

Meniscus injuries are common in multiple sports, said researcher Dr. Ziad Abusara, and arthritic problems are one of the leading causes of disability in the world.

By 2040, one in four Canadians is expected to have osteoarthritis, and medical costs for arthritis add up to more than $33 billion each year, according to a 2011 report from the Arthritis Alliance of Canada.

Now, the researchers hope to figure out how to slow cell death after knee surgery before osteoarthritis sets in.

"The ultimate goal of course is to reverse it, but at least for now we want to try and stop it," Abusara said.