Too Late, or Too Soon: Knee Replacement Timing Is Often Off

Delayed surgery reduces benefits; premature surgery raises risks

The timing of knee replacement surgery is critical to getting the most benefit. But among patients with knee osteoarthritis, 90% who could benefit from a knee replacement wait too long and get less benefit, while about 25% needlessly get a new knee too soon when the benefit is minimal, a Northwestern Medicine study finds.

This is believed to be the first study to prospectively examine the timeliness of knee replacement among a large number of patients with knee osteoarthritis who could benefit from the surgery. Prior studies have quantified timeliness of surgery only among patients who already had a knee replacement, and these studies generally involved fewer patients.

"When people wait too long, two things happen," said lead investigator Hassan Ghomrawi, PhD, MPH, associate professor of surgery at Northwestern University Feinberg School of Medicine. First, he said, "The osteoarthritis causes deterioration of their function. Some of them wouldn't be able to straighten out their legs, affecting their walking and mobility. When you can't get exercise, you can start to develop other health problems such as cardiovascular problems. You may also become depressed. The overall impact can be huge."

The second problem with delaying surgery is less benefit. "You don't get as much function back when you wait too long; your mobility is still reduced versus somebody who had it in a timely fashion," Dr. Ghomrawi said.

African-Americans delayed knee replacement surgery more than Caucasians, the study found.

The ideal timing of knee replacement surgery is based on an algorithm that factors in pain, joint function, radiographic assessment, and age to determine if a person will benefit from surgery. Getting knee replacement surgery too early based on the algorithm means patients are having major surgery with risk of complications and getting minimal benefit. They may also need a revision (second surgery) later in life, which is much more difficult surgery with poorer outcomes than the original surgery.

Nearly 1 million knee replacement procedures are performed in the U.S. each year, with projections of a rapid increase by 2030.

The Northwestern study was based on 8,002 participants who had or were at risk for knee osteoarthritis and were followed for up to eight years as part of two diverse multicenter trials, the Osteoarthritis Initiative and Multicenter Osteoarthritis. The study was published in the Journal of Bone and Joint Surgery.

Source: Northwestern University, January 13, 2020