A knee replacement should only be considered after all non-surgical treatments for osteoarthritis of the knee have failed, say health authorities.

A total knee replacement should be a "last resort" treatment of osteoarthritis, with those with the common condition encouraged to loose weight and do more exercise.

The Australian Commission on Safety and Quality in Health Care released on Friday it's new clinical care standard for treating knee osteoarthritis.

It suggests life-style measures and pain-relieving medications are the gold standard for high quality care.

Only when a patient's symptoms fail to respond to these less invasive, non-surgical options should a knee replacement be considered.

The commission's new standard has been endorsed by nine leading health, medical and consumer organisations, including Arthritis Australia.

About 2.1 million Australians are living with osteoarthritis, costing the health systems billions of dollars every year.

This number is expected to climb as the population ages and the prevalence of obesity increases, warns the commission's clinical director Dr Robert Herkes.

Patients who are overweight have double the risk of developing osteoarthritis, the risk is four-fold for obese patients.

Accroding to Dr Herkes, 70 per cent of knee replacements were carried out on patients whose weight was contributing to their osteoarthritis.

"But fewer than eight per cent of Australians incorporate weight loss as part of their osteoarthritis treatment," he said.

The Royal Australiasian College of Surgeons (RACS) Annual Scientific Congress (ASC) in Adelaide last week was told that obesity puts extra pressure on joints and limbs and make surgical procedures such as joint replacement more necessary, but also more dangerous.

Dr John McNicholl, orthopaedic registrar at Queensland's Toowoomba Hospital, said: "Our audits have identified obese patients who undergo either hip or knee arthroplasty are more likely to return to hospital, and more likely to suffer infections that require re- operation."

According to Dr McNicholl, his hospital has ceased to offer arthroplasty, or total joint replacement, to patients who present with a body mass index (BMI) of more than 40.

This is in line with recommendations from the American Academy of Orthopaedic Surgeons (AAOS).

Dr Herkes says it's "crucial" that clinicians provide patient education and help them self-manage their pain, as well as encourage them to remain active.