Surgery better for relieving knee pain

A hand holding a skeleton structure of a human knee with an artificial implant from bicompartmental knee replacement procedure, where two worn-out parts of the knee are replaced with two artificial implants.

Knee replacement surgery relieves pain and improves function in patients with severe osteoarthritis much more effectively than non-surgical therapy alone, researchers reported last week.

Despite hundreds of thousands of knee replacements performed in the United States yearly, until now there had been no rigorously controlled trial comparing the operation with more conservative approaches.

In the new study, 50 adults with moderate to severe osteoarthritis completed exhaustive non-surgical treatment, including exercise and supervised weight loss. A similar group of patients received knee replacements, followed by the non-surgical therapy.

After a year, 85 per cent of patients who got an artificial knee reported pain relief and functional improvement, the study found, compared with 68 per cent of patients initially assigned to non-surgical treatment. The study was published in The New England Journal Of Medicine.

"Surgery is much better at improving pain than physical therapy," said Dr Jeffrey Katz, director of the Orthopaedic and Arthritis Centre for Outcomes Research at Brigham and Women's Hospital in the US, who wrote an editorial accompanying the report.

"But at the same time, it's a little bit surprising that this physical therapy regimen was associated with substantial pain relief."

Most surgeons have assumed that total knee replacement provides superior results. But experts said this new trial suggests that patients with severe osteoarthritis and difficulty walking should not always go under the knife.

A quarter of the patients assigned to the therapy-only group eventually opted for operations. But the researchers still counted them as non-surgical patients. So the difference between groups might have been even bigger.

The number of knee replacements has risen drastically in the US, the study's authors noted. In 2012, more than 670,000 knee replacements were performed at a cost of US$36.1 billion (S$50 billion).

And the rate of surgery almost doubled from 2000 to 2010, according to a report published last month by the Department of Health and Human Services.

Knee replacements can last a decade or longer before failing.

Dr Soren Skou, the study's lead author and a physical therapist at Aalborg University Hospital and at the University of Southern Denmark, said the rationale for doing the trial was to pinpoint the degree of added benefit for surgical patients, compared with treatment alternatives.

All 100 participants in Dr Skou's study were in their mid-60s, slightly obese and candidates for total knee replacement. They reported moderate pain and difficulty functioning, and X-rays confirmed moderate to severe arthritis. People with severe pain were excluded.

However, in the latest study, the surgery group experienced a total of 24 serious adverse events, like blood clots, deep infections or knees so stiff they had to be manipulated under anaesthesia. The non-surgical group had just six.

Dr Mathias Bostrom, an orthopaedic surgeon at the Hospital for Special Surgery in the US, said the study was "very well done from a methodological standpoint", but its complication rate was "higher than I would have expected".

This article was first published on October 27, 2015. Get a copy of The Straits Times or go to for more stories.