One-Third of Knee Replacements Unnecessary, Half Questionable: Study

The findings of a new study suggest that up to one third of all total knee arthrplasty may be unnecessary, placing patients at risk of surgical complications and knee replacement failures without providing any appreciable benefit. 

The study was published in the medical journal Arthritis & Rheumatology late last month, finding that many patients who received unnecessary knee replacements originally had symptoms that were moderate, with little joint damage.

Researchers from Virginia Commonwealth University in Richmond looked at data on about 4,800 people in the U.S. who had, or were at high risk of, knee osteoarthritis. They determined that 205 of those underwent total knee replacement surgery.

The study found that 34% of the surgeries were inappropriate when they used standard accepted criteria, and another 22% were inconclusive. Only 44% of the surgeries were deemed appropriate. The researchers had anticipated that only about 20% of the surgeries would be considered inappropriate.

Researchers noted that the standards for determining who should undergo total knee replacement did change since the study was first began. However, they said it demonstrates a lack of consensus among orthopedic surgeons as to when total knee replacement surgery is warranted. The study was funded in part by the National Institute of Health and Merck.

In addition to facing the risk of complications associated with knee replacement surgery, the study raises concerns about unnecessarily exposing patients to the risks associated with implants that may later develop problems or be found to contain design defects.

More than 1,000 patients who previously received Zimmer NexGen knee implants are now pursuing product liability lawsuits, alleging that doctors implanted a defectively designed and unreasonably dangerous implant. The Zimmer NexGen system was first introduced in 1995, with most components later approved without extensive trials or FDA investigation into their safety through the 510K fast-track approval program, which only requires that devices be “substantially equivalent” to medical devices already on the market to obtain marketing approval. All of the plaintiffs now claim that they experienced problems with certain Zimmer knee replacements, which were allegedly caused by design problems and Zimmer’s failure to provide accurate information about the risks associated with the implant.