Keyhole knee surgery should not be performed on patients with a type of arthritis in the joint, experts have said,
Knee arthroscopy - a type of keyhole surgery used to both diagnose and treat problems in joints - is not recommended in almost all patients with degenerative knee disease, according to a new "rapid recommendation" published in the British Medical Journal.
A panel of international experts argue that all the evidence suggests that surgery does not result in a lasting improvement in pain or function for those with degenerative knee disease - also known as osteoarthritis of the knee.
The experts, made up of bone surgeons, physiotherapists, clinicians and patients with experience of degenerative knee disease, carried out a detailed analysis of the evidence available on the treatment - which is performed around two million times each year around the globe.
A linked review of 13 random control trials and 12 observational studies concluded the treatment does not reap "important benefits" in pain or function.
The researchers found that when compared with "conservative management" - including exercise therapy or medication - the surgery results in a very small reduction in pain up to three months following the procedure and very small or no pain reduction up to two years later.
Meanwhile, they found that knee arthroscopy results in a very small improvement in the short term and very small or no improved function up to two years after the operation.
The rapid recommendation concludes: "We make a strong recommendation against the use of arthroscopy in nearly all patients with degenerative knee disease, based on linked systematic reviews.
"Further research is unlikely to alter this recommendation."
Professor Mark Wilkinson, Arthritis Research UK spokesman and professor of orthopaedics at the University of Sheffield, said: "Degenerative arthritis is a group of conditions where the main problem is damage to the cartilage which covers the ends of the bones.
"Painful and debilitating degenerative knee arthritis affects around four million people in the UK.
"Previous studies have shown that knee arthroscopy is not recommended for the symptoms of pain and loss of function for people with degenerative knee arthritis.
"People with mechanical symptoms, such as locked knee, are more likely to benefit for this type of surgery. Current guidelines support this.
"Anyone with pain and loss of function in their knee joints will find benefit from lifestyle modification, exercise, physiotherapy, suitable pain medication, or joint replacement when non-surgical treatment becomes no longer effective."