A dramatic increase in surgical knee replacement has some researchers concerned that the procedure may be misused.
The ratio of Medicare patients undergoing total knee arthroplasty (TKA) jumped 99.2% between 1991 and 2010, from 31.2 procedures per 10,000 Medicare enrollees to 62.1 procedures per 10,000 enrollees, according to a new study.
"The growth in TKA should prompt consideration of whether too many (or too few) of these procedures are being performed both in aggregate and among key patient subgroups defined by race, sex, or age," the authors wrote.
TKA is "one of the most common and costly" surgical procedures performed in the U.S., typically used for patients with severe knee arthritis, but there are few studies examining usage trends, the researchers noted.
The study found that the total number of TKA surgeries among Medicare patients grew 161.5% from 93,230 to 243,802 between 1991 and 2010, driven partly by increased enrollment in the federal healthcare program.
The Medicare population represents about 40% of the approximately 600,000 TKA procedures performed per year. At a cost of about $15,000 per procedure, knee replacements are a $9 billion market, according to a press release.
"This growth is likely driven by a combination of factors including an expansion in the types of patients considered likely to benefit from TKA, an aging population, and an increasing prevalence of certain conditions that predispose patients to osteoarthritis, most notably obesity," according to the researchers.
During the 20-year time period analyzed by researchers the prevalence of obesity among TKA patients nearly tripled from 4% to 11.5%.
As knee replacement surgeries became more popular, patient hospital stays following the procedure dropped from 7.9 days to just 3.5 days, researchers found. All-cause post-procedure complications leading to 30-day readmission rose from an average of 4.2% in 1991-1994 to 5% in 2007-2010.
One of those post-procedure complications could be a heart attack. Earlier this year a study published in the Archives of Internal Medicine found that the heart attack rate for patients may increase 25-fold following knee or hip replacement surgeries, although the effect was most pronounced in hip replacement patients.
Overall complication rates were similar for TKA revision surgeries. The per capita rate of TKA revision in 1991 was 3.2 procedures per 10,000 Medicare patients, which jumped to 5.1 by 2010.
"For revision TKA, a decrease in hospital [length of stay] was accompanied by an increase in all-cause 30-day readmission from 6.1% to 8.9% and an increase in readmission for wound infection from 1.4% to 3.0%," according to a press release.
The research team, based at the University of Iowa Carver College of Medicine, evaluated trends in primary and revision TKA in the U.S. Medicare population, including more than 3.2 million patients who underwent TKA and more than 300,000 who underwent revision TKA.
"In an effort to control costs and improve quality of care, the findings provide important information concerning patient demographics associated with primary and revision total knee replacements and complications," New York University Langone Medical Center Drs. James Slover and Joseph Zuckerman wrote in an editorial accompanying the study. "In the currently challenging and dynamic health care environment, critical evaluation and systematic data collection about total knee replacements will be needed to optimize outcomes and ensure access to these life-improving procedures."
The TKA field represents big business for medical devices makers, and some are hoping to get a part of that market by attacking the problem before it leads to surgery. California-based device maker DJO Global is hoping its line of knee braces can help patients forgo total knee replacement surgery, possibly for years.
"Osteoarthritis is probably more relevant today than getting a sunburn," DJO sales & marketing director Brian More told MassDevice.com during an interview published last month. "1 in every 2 people has some form of osteoarthritis. If you get in a room, there’s definitely someone in there with knee pain."