A surgery commonly used to treat knee pain in osteoarthritis patients may not only be less effective than believed, but could actually worsen knee health over time, according to a new study from Finland published in the prestigious The New England Journal of Medicine.

The research focused on partial meniscectomy, a procedure in which surgeons remove damaged portions of the meniscus — the rubbery, C-shaped cartilage in the knee that acts as a shock absorber between the thigh bone and shin bone.

For years, doctors believed that tears in the meniscus were one of the main causes of knee pain, especially in older adults with osteoarthritis. However, the new findings challenge that long-standing belief.

Researchers followed patients for 10 years and found that those who underwent meniscus removal surgery had worse outcomes compared to patients who received “sham” surgery, where doctors performed a procedure without actually removing any cartilage.

Surprisingly, patients in the sham surgery group reported less pain, better movement, and slower progression of osteoarthritis than those who had the actual surgery.

According to Teppo L.N. Järvinen, the senior investigator of the study, meniscus tears may not always be the true source of pain.

“There is now substantial evidence suggesting that we may have been targeting the wrong problem,” he said.

Experts say meniscus tears are extremely common in middle-aged and older adults, including many people who experience no knee pain at all. This suggests that the visible tear may not necessarily be responsible for the symptoms.

Clint Soppe of Cedars-Sinai, who was not involved in the study, said doctors once believed they could clearly separate arthritis pain from meniscus pain. But with growing understanding of inflammation and chronic pain, that distinction is becoming less clear.

He explained that several inflammatory substances inside the joint — including cytokines and enzymes — may play a larger role in pain than previously understood.

The findings are now pushing experts to rethink how knee osteoarthritis should be treated.

Instead of surgery, doctors are increasingly recommending conservative treatments such as physical therapy, anti-inflammatory medicines, rest, icing, cycling, and injection therapies like cortisone, hyaluronic acid, and platelet-rich plasma therapy.

Soppe said surgery may still help in selected cases where the torn meniscus is severely displaced and causing mechanical problems inside the knee. However, he added that many patients may benefit more from non-surgical care, while some with advanced osteoarthritis could eventually require full knee replacement instead.

Interestingly, the study has also sparked debate over whether the “sham” surgery itself may have offered some relief. During the procedure, doctors flushed the knee joint with saline fluid, a process known as lavage.

Soppe noted that this flushing may have reduced inflammation by removing pain-related chemicals from the joint, which could partly explain why patients in the sham group felt better.

The study is expected to fuel wider discussions in the orthopedic community and may lead to major changes in how knee osteoarthritis and meniscus tears are treated in the future.