Another Nail in The Coffin for
Arthroscopic partial meniscectomy is the most common orthopedic procedure performed in the U.S., according to the CDC’s National Health Statistics Reports. There are approximately 700,000 of these surgeries performed annually. Aimed at eliminating pain from degenerative meniscal tear, in recent years these surgeries, specifically those performed on patients with no knee osteoarthritis, are seeing their efficacy increasingly called into question.
A torn meniscus does not have to be the result of a traumatic sports injury. Degenerative tears are somewhat common in older adults, occurring through regular wear and tear of the thin strip of cartilage that absorbs shock in the knee. These degenerative tears, it turns out, often do not improve with surgery.
The latest study, published in July in BMJ along with an editorial condemning these surgeries, found that among 140 middle-aged patients with medial degenerative meniscal tears but no accompanying osteoarthritis, no significant difference in patient-reported pain, symptoms, knee function or other knee-related quality of life was found during two years’ follow-up after arthroscopic partial meniscectomy as opposed to a sub-group receiving neuromuscular and strength training over 12 weeks.
The exercise group, unsurprisingly, had greater improvements in muscle strength. About 80% of the patients in both groups did see a clinically meaningful improvement—but if the improvement from an exercise and physical therapy regimen matched surgical outcomes, why resort to meniscal tear arthroscopy?
MRI scanning, in fact, often reveals meniscal tears in people who have no symptoms or pain. This clouds the issue of what is the underlying cause of the pain, and whether surgery helps at all to treat it. Patients with pain often also have knee osteoarthritis, pointing the finger to the possible real cause, since asymptomatic patients often only learn of a meniscal tear after an MRI discovers it. A meta-analysis published last year of nine clinical trials testing the surgery concluded that it did little for most patients, who reported less pain, but that was a finding regardless of the treatment, even fake surgery. The act of undergoing surgery seems to offer a placebo effect.
Before both the July study and last year’s meta-analysis, in December 2013, the results of a parallel group study of five orthopedic clinics in Finland called the surgical practice into question in the NEJM, where the study was published:
“[T]he results of this randomized, sham-controlled trial show that arthroscopic partial medial meniscectomy provides no significant benefit over sham surgery in patients with a degenerative meniscal tear and no knee osteoarthritis. These results argue against the current practice of performing arthroscopic partial meniscectomy in patients with a degenerative meniscal tear.”
The evidence against the procedure for those without OA, which has been mounting for some time, makes one wonder why these surgeries continue to get scheduled. As Dr. David Kallmes of the Mayo Clinic told The New York Times in an article published in The Upshot, he believes there may be a kind of doctor confirmation bias at play in which surgeons tend to remember only their success stories: the patients who seemed better afterward.
“The successful patient is burned into their memories and the not-so-successful patient is not,” Dr. Kallmes said. “Doctors can have a selective memory that leads them to conclude that, ‘Darn it, it works pretty well.’”
It is time to take a hard look at this surgery, and whether an inadvertent bias in favor of it does exist and has kept us from seeing it for what it is: little better than a sham.