(Reuters Health) - Many middle-aged and older adults with torn cartilage and pain in their knee are not likely to benefit from so-called arthroscopic surgery, a review of past studies suggests.

Researchers analyzed 10 previous clinical trials that randomly offered some patients knee surgery and others nonsurgical options including exercise or medication. Overall, knee surgery was no better than these alternatives for improving physical function, and resulted in only a small reduction in pain.

However, when researchers looked just at a subset of patients without knee pain from arthritis in their knee, surgery did appear moderately better than physical therapy for reducing pain from the tear.

“Surgery does not work for everyone but in selected cases we show that surgery should be available to patients,” said lead study author Simon Abram of the University of Oxford in the UK.

“In most circumstances, patients should try physiotherapy first,” Abram said by email. “If this does not improve symptoms, knee surgery may be beneficial, especially in patients without osteoarthritis and with specific symptoms.”

Worldwide, more than 4 million people get arthroscopic knee surgery each year, according to the American Orthopedic Society for Sports Medicine.

During the operation, a surgeon makes a small incision in the knee and inserts a tiny camera called an arthroscope to view the inside of the joint, locate and diagnose the problem, and guide repairs. Sometimes surgeons remove all of the meniscus, the cartilage that works as a cushion between the shin and thigh bones, and other times they only remove part of it.

While this is minimally invasive, it’s not risk-free. Patients receive anesthesia, which in any surgery may lead to complications such as allergic reactions or breathing difficulties. In addition, this specific procedure might potentially damage the knee or trigger blood clots in the leg.

In the current analysis, all of the trial participants who got knee operations had a partial meniscectomy, removing only some of this cartilage.

For all types of patients - including people with and without arthritis pain - surgery was slightly better than physical therapy at reducing pain after 6 to 12 months, an analysis of five trials with a total of 943 patients found.

In three trials of 402 patients without arthritis pain, surgery had a small to moderate advantage in knee pain improvement after 6 to 12 months over physical therapy.

Two trials with 244 patients without arthritis pain also found surgery associated with a moderate to much larger improvement in quality of life than nonsurgical treatment.

One limitation of the analysis is that none of the smaller trials had long-term outcomes, researchers note. Another drawback is that pain and quality of life assessments in the smaller studies may have been of poor quality or incomplete in some instances.

The analysis also focused on patients in their 40s and 50s, and may not reflect what would happen with younger adults, said Dr. Jonas Bloch Thorlund, a sports medicine researcher at the University of Southern Denmark in Odense who wasn’t involved in the study.

“The effect of meniscal surgery for younger populations 18-40 years has never been compared with non-surgical treatments (exercise therapy or placebo),” Thorlund said by email. “The best treatment - surgical or non-surgical - remains to be established in this younger patient group.”

Even so, the results may help doctors better determine which older patients might benefit from knee surgery, said Dr. Kyle Hammond of the Emory University Sports Medicine Center in Atlanta.

“Patients who benefit from meniscal surgery, tend to have minimal arthritis and/or a displaced meniscal tear, like a ‘hang-nail’ that is causing them discrete mechanical symptoms (catching or locking sensations in the knee joint) with provocative actions both in life activities, (and) also during the physician’s physical exam,” Hammond, who wasn’t involved in the study, said by email.

“The . . . patient may not benefit from arthroscopy when the patient’s knee pain is more consistent with kneecap pain sources and/or other arthritic pain sources,” Hammond added. “In these instances, the physician should consider a non-surgical approach, such as physical therapy, a knee injection and/or an anti-inflammatory program.”

SOURCE: bit.ly/2IY4pmW British Journal of Sports Medicine, online February 22, 2019.