There are more than 600,000 knee replacements performed each year in the United States, according to figures from the Agency for Healthcare Research and Quality. Medical News Today reports that this surgery has become more common in the past 15 years, but a recent study published in Arthritis & Rheumatology shows that about one-third of total knee replacements are “inappropriate” when applied to a Spanish patient classification system.
Between 1991 and 2010, studies show that there was an annual volume increased on 162 percent in Medicare-covered knee replacement surgeries. Some experts argue that the growth shows how effective the procedures are, while others say that it is applied unnecessarily. The latter say that the surgery “is highly reliant on subjective criteria.”
In this study, researchers from the Virginia Commonwealth University in Richman looked at the criteria used to determine if a total knee arthroplasty (TKA) is appropriate. The authors noted that this has not been studied before in the US although it has been developed in other countries. Lead author Dr. Daniel Riddle from the Department of Physical Therapy at Virginia Commonwealth University said “To my knowledge, ours is the first US study to compare validated appropriateness criteria with actual cases of knee replacement surgery,”
The researchers looked a modified version of an appropriateness classification system developed in Span and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain and Physical Function scale. Many experts in the field consider this criteria to be “among the most powerful tools for improving quality of care and controlling costs” the authors said.
Riddle and his colleagues used the classification systems to look at a sub-set of 175 people who underwent TKA and were enrolled in the Osteoarthritis-Initiative, a 5 year study funded by the National Institutes of Health (NIH). The researchers found that 34 percent were “inappropriate”, 44 percent were “appropriate” and 22 percent were “inconclusive”.
“Our finding that one third of knee replacements were inappropriate was higher than expected and linked to variation in knee pain [osteoarthritis] severity and functional loss,” Riddle says. “These data highlight the need to develop patient selection criteria in the US.”