JAMA Identifies Rapid Rise in Knee Replacements

The Journal of the American Medical Association (JAMA) has released a study of Medicare data that shows a rise in knee replacements among senior citizens. With total knee arthroplasty (TKA) being one of the most common and costly surgical procedures performed in the United States, JAMA studied more than 3 million patients over the age of 65 who underwent primary TKA and more than 300,000 patients who underwent revision TKA to examine longitudinal trends in volume, utilization, and outcomes for both procedures between 1991 and 2010 in the U.S. Medicare population.

Researchers found that over the past 20 years, first-time and revision TKAs in the United States increased 161 percent and 105 percent respectively. By 2010, 62 of every 10,000 older adults were getting primary knee replacement surgery every year. The procedure typically is aimed at people with very bad knee pain, often accompanied by advanced arthritis, for whom anti-inflammatory drugs or physical therapy provide no relief. The procedure consists of removing cartilage and bone from around the joint and replacing it with an artificial joint made from metal or a polymer.

“As people are aging healthier than they used to, they want to maintain their activity throughout their lives,” lead study author Peter Cram, M.D., from the University of Iowa Carver College of Medicine in Iowa City, Iowa, told Reuters Health. “They want to play with their grandkids, they want to ski, they want to hike the Appalachian Trail – and knee replacement allows them to do that. [But] at $15,000 a pop, this adds up to real dollars.”

During the period studied, the number of patients seeking TKAs and revision surgeries grew much faster than the number of elderly patients covered under Medicare. Simultaneously, the number of knee replacement patients with comorbid conditions such as diabetes and obesity also doubled. However, the time spent in hospital following TKA surgery dropped from eight days to 3.5 days, while the need for readmission rose slightly. Rates of serious complications such as infection or heart problems linked to a first time TKA remained the same. During the study period, approximately 0.5 percent of patients died within a month of surgery.

James Slover of the New York University Langone Medical Center in New York, N.Y., co-wrote a response to the JAMA study. He noted that seniors typically become healthier after a TKA procedure, as the extensive rehabilitation and walking motion required afterward forces them to stay or become active. However, Cram said the idea that healthier seniors post-TKA surgery would offset the cost of TKAs themselves is “wishful thinking.”

It is likely that the trend JAMA has identified will sustain as baby boomers continue aging. “What we’re seeing now may be the tip of the iceberg for what we’re seeing in 20 or 30 years,” Slover said.

Image of total knee replacement courtesy of Meriter Health Services.