"On a scale of 1 to 10 for pain, surgery did not result in a significant improvement, less than a 1-point difference," Khan said.
Functioning scores, which took into account how well patients could walk, climb stairs or go about daily activities, were also similar in each group, Khan said.
The conclusions apply only to those in their 50s who have mild arthritis of the knee and also age-related chronic tears of the meniscus, he said.
Kahn said the findings don't apply to people who have "acute" tears, those caused by injury, for instance.
"I think surgeons will look on this [finding] favorably, as we all want to do what is best for the patient," he said.
The new analysis reflects the findings of other research, said Dr. Leon Popovitz, an orthopedic surgeon at Lenox Hill Hospital in New York City, who wasn't involved in the study.
"Studies are changing the perspective of knee arthroscopy," he said. "While it used to be thought all meniscal tears need arthroscopic surgery, it's just not the case."
Popovitz tells patients, "If you do have the beginnings of arthritis and a meniscal tear and don't have mechanical symptoms, you really need to exhaust all conservative measures before pursuing arthroscopic surgery."
Some patients eventually will need the surgery, Popovitz said, but some could be spared.
It's still "an excellent operation" that can help many people, he added, "especially those who do not have arthritis."
Doctors can identify arthritis in the knee by X-ray, Popovitz said.
Dr. Mohit Bhandari, a co-author of the paper, reports consultancy payments and grant support from medical device makers and biopharmaceutical companies.
To learn more about knee arthroscopy, see the America
All rights reserved