Share on Pinterest
More Americans are getting their knees replaced. Getty Images
  • Americans have more than 600,000 knee replacements each year. That number is expected to reach 1.28 million by 2030.
  • A new study finds that 90 percent of patients with osteoarthritis in their knees wait too long to get a replacement.
  • Experts devised a new algorithm to help physicians and patients figure out the right time to have surgery.

Want to get the most from a total knee replacement? Make sure you have the procedure done at the right time.

A report published today in the Journal of Bone and Joint Surgery found that delaying surgery can deprive patients of the surgery’s full benefits. But when surgery is done too soon, patients put themselves at risk and may wind up needing another replacement.

According to the report, about 90 percent of patients with knee osteoarthritis are waiting too long to have the procedure. And about 25 percent of people who don’t yet need it are having the procedure done too soon and only experiencing minimal benefits.

“People are waiting and waiting to have the procedure and losing the most benefit,” said Hassan Ghomrawi, PhD, MPH, associate professor of surgery at Northwestern University Feinberg School of Medicine.

Ghomrawi’s team devised an algorithm that incorporates joint function, pain, radiographic assessment, and age to best determine the optimal time to have a knee replacement. It was based on information from 8,002 people who had or were at risk for osteoarthritis. Researchers followed up on the patients for up to 8 years.

In patients who wait too long, the osteoarthritis deteriorates their function. This means they can’t exercise or be active, which can lead to other health problems, including depression.

Also, patients who wait too long don’t get as much function back after surgery. “Your mobility is still reduced versus somebody who had it in a timely fashion,” Ghomrawi explained.

Patients who have surgery too soon put themselves at risk for complications and may wind up having a revision surgery later in life. Revisions can be more difficult and result in poorer outcomes.

Socioeconomic issues play a big role in timing as well, he noted. Black people delayed knee replacement surgery more than white people, the study found.

Some people go for surgery too soon because they’re the sole source of income for their family, and they want to take care of themselves. Others may delay surgery if they’re caring for an aging loved one, he noted.

“Incorporating these algorithms to assess patient’s knee osteoarthritis at the primary care level and at the orthopedic surgeon level would improve timing of knee replacement,” Ghomrawi said.

“From my experience, most adults wait too long to have a knee surgery… specifically replacement,” said Morgan Nolte, a geriatric physical therapist from Nebraska. The older someone is, the more likely they have multiple co-existing health conditions, such as high blood pressure or diabetes, and those can complicate recovery.

“Lean muscle mass also declines with age, so the physical effort of recovery can seem harder than if the surgery was performed a bit earlier in life,” she told Healthline.

“Many patients who undergo a knee surgery have reported to me they wished they would have got it earlier for a faster recovery, but also to enjoy more years with less pain,” she added.

Dr. Seth S. Leopold, an orthopedic surgeon, professor at the University of Washington and editor-in-chief of the journal Clinical Orthopedics and Related Research, said he would take the findings with a “large lump of salt.”

“Both what I see in practice as a high-volume joint replacement surgeon and as the editor of an orthopedic surgery journal suggests to me that if anything, surgeons recommend knee replacement too easily and too often,” he said.

“I have deep reservations about even a thorough, well-intentioned investigator’s ability to conclude from a necessarily superficial chart analysis that some 80 to 90 percent or more of patients are good candidates for knee replacement, but that surgeons — who generally like to help people, generally like to operate, and generally get paid by the piece — for some reason withhold the operation,” he said. “It just doesn’t reflect the reality I see either as a surgeon or as the editor of a large surgical journal.”

The recovery may be slower or less complete if someone waits too long, but that’s only the case if they wait “way too long,” he said.

Patients and doctors should first look at nonsurgical interventions to attempt managing symptoms.

“Only if they can’t, and only if the pain and limitations are pretty severe, does joint replacement make sense to me,” he noted.

Leopold knows of many patients who have the procedure done so they can stay active. But about 20 percent still have pain after recovery and others have serious complications. “That strikes me as a too enthusiastic use of a serious intervention,” he said.

“As good as this study was, I hope that surgeons and patients don’t use it as a license to recommend or undergo this major surgical procedure too early,” he said. “Some of the complications of this operation are serious, irreversible, and life-changing. It isn’t something that as a knee replacement specialist I recommend lightly.”

With an aging population, more and more Americans are undergoing knee replacement surgery.

Americans have more than 600,000 knee replacements each year. That number is expected to reach 1.28 million by 2030, according to data from the American Academy of Orthopaedic Surgeons.

Overall, Ghomrawi hopes people use his algorithm to better predict the best timing for surgery.

“Knee replacement is one of the most successful surgical procedures, and done at the right time, could provide a lot of benefit in terms of pain relief and functional recovery, and has proven to be highly cost-effective,” he said.