Are Total Knee Replacements Being Performed Too Often or Too Little?

The Gist

Total knee replacement, also known as total knee arthroplasty, is one of the most common and most expensive surgical procedures carried out in the United States. It is a common treatment for knee pain associated with osteoarthritis and similarly serious conditions. A newly published study by the Journal of the American Medical Association (JAMA) takes a closer look at the sharp uptick in total knee replacement procedures conducted in the United States during the past 20 years. 

The study, led by Dr. Peter Cram, MD, MBA, looked at almost 3.5 million procedures conducted since 1991 among the Medicare population (all of whom are over age 65), and found that hospital stays for the procedure have decreased in length during that time. However, there have also been increased rates of infectious complications after the procedure, as well as increased rates of readmission to the hospital in the month following the procedure.

The Expert Take

Dr. Brian Wolf, MD, MS, an Orthopaedic Surgeon and Associate Professor at the University of Iowa Department of Orthopaedics and Rehabilitation, and a co-author of this study, spoke with Healthline about the findings.

“We found that the number of people having total knee replacements is going up even faster than the population of [Medicare age] is increasing,” explained Dr. Wolf. There are a number of possible reasons for this, including:

• a broader field of patients considered to qualify for the procedure
• higher prevalence of conditions that can result in osteoarthritis, and thus the need for total knee replacement, especially obesity
• the United States’ aging population

The increased use also has to do with the surgery’s success rate, explains Dr. Wolf. “It’s proven to be an excellent operation in improving quality of life,” he says. The risks and complications of total knee replacement, as he explains, are relatively low—in the neighborhood of 4 or 5 percent—and have remained so for several years. For reasons such as this, surgeons are more likely to consider knee replacement for an obese person today than they would have been 20 years ago.

Beyond these facts, Dr. Wolf postulates that these trends in the usage of total kne replacement reflect a population that is more active and less tolerant of knee pain, especially given the success rate of this procedure.

A significant, related discovery of this study showed that the number of days people would stay in the hospital for this procedure dropped dramatically in the time period studied: from an average of 9 to 3.5 days. This number partly has to do with the economics of healthcare, says Dr. Wolf, but it has a significant downside. “The downside to [this statistic] is that we noticed more people didn’t necessarily go home after surgery, but rather went to a field facility, nursing home, or rehab center.” As is discussed in the study, there was a slight increase in the number of people who had to be readmitted to the hospital within 30 days of surgery. In prior years, suggests Dr. Wolf, conditions requiring readmission might have been caught earlier if patients had stayed longer in the hospital.