Patient-surgeon consensus needed in determining candidates for knee replacement surgery

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More than one-third of total knee replacement procedures examined in a recent study were classified as “inappropriate” based on a modified appropriateness classification system.

Virginia Commonwealth University led the research, which was published this week in Arthritis & Rheumatology, a journal of the American College of Rheumatology.

“Our study really demonstrated that there is extensive variation in the amount of pain, the amount of functional loss and the amount of osteoarthritis people have when they undergo knee replacement surgery,” said lead author Daniel Riddle, Ph.D., professor in the Department of Physical Therapy, VCU School of Allied Health Professions. “And this study helps to lay the groundwork for consensus-building approaches by patients, by surgeons and by health care policymakers to come to a better idea as to what characteristics a patient should have before they undergo knee replacement surgery.”

The Agency for Healthcare Research and Quality reports more than 600,000 knee replacements are performed in the U.S. each year, according to a press release from the journal’s publisher: “In the past 15 years, the use of total knee arthroplasty has grown significantly, with studies showing an annual volume increase of 162 percent in Medicare-covered knee replacement surgeries between 1991 and 2010. Some experts believe the growth is due to use of an effective procedure, while others contend there is over-use of the surgery that relies on subjective criteria.”

Riddle’s study used an appropriateness classification system to assess participants enrolled in the Osteoarthritis Initiative — a prospective five-year study funded in part by the National Institutes of Health. Of the 175 total knee replacement surgeries studied, 44 percent were classified as appropriate, 22 percent as inconclusive and 34 percent as inappropriate.

Riddle said ensuring that only necessary procedures are administered begins with the patient.

“It is the patient that ultimately decides whether or not they’re going to undergo the procedure,” he said. “So it boils down to patients having clear expectations of what they’d like their outcomes to be and discussing with their surgeon whether those expectations are in the  ballpark given the patient’s preoperative status. We know for example from this and other studies that patients who have mild osteoarthritis are at greater risk for a poor outcome.”

Riddle found in his study that 10 percent of the sample had no knee joint space narrowing prior to surgery.

“These types of prognostic factors need to be considered by both the patient and surgeon as part of the decision-making process,” Riddle said.

The full study can be accessed at


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