Timing of knee replacement surgery very important: study

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, a study of Northwestern University (NU) showed.

The NU 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 found that 90 percent of patients with knee osteoarthritis who would potentially benefit from knee replacement are waiting too long to have it and getting less benefit, while about 25 percent of patients who don't need it are having it prematurely when the benefit is minimal.

"When people wait too long, two things happen," said lead investigator Hassan Ghomrawi, associate professor of surgery at NU Feinberg School of Medicine. "The osteoarthritis causes deterioration of their function. Some of them wouldn't be able to straighten out their legs, affecting their walking and mobility."

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," Ghomrawi said.

Meanwhile, 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 second surgery later in life, which is a much more difficult surgery with poorer outcomes than the original surgery.

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

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.

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

The study was published on Monday in the Journal of Bone and Joint Surgery.