The research that’s changing how we treat knee osteoarthritis

Published August 2025 | 5 min read
Expert contributors: Ian Harris, Professor of Orthopaedic Surgery at UNSW Sydney; Ilana Ackerman, Professor (Research) at Monash University’s School of Public Health and Preventive Medicine; Claire Ashton-James, Associate Professor, Pain Management at the University of Sydney School of Medicine; Professor Justine Naylor, UNSW Medicine & Health’s School of Clinical Medicine
Words by Sabrina Rogers-Anderson

Surgery used to be the main treatment for knee osteoarthritis, but research funded by the HCF Research Foundation is exploring how to keep you out of hospital.

Most of us have heard of knee osteoarthritis – around 1.2 million Aussies live with this chronic disease that involves inflammation and structural changes in one or both knee joints. It can lead to pain, swelling, stiffness, impaired mobility and reduced quality of life.

Over the past 25 years, the HCF Research Foundation has invested more than $3.7 million in funding over 16 research projects aimed at providing better health outcomes to people with knee osteoarthritis. Here, we speak with leading Australian researchers about the latest insights and developments in knee osteoarthritis treatment.

Making informed choices about knee replacement surgery

More than 55,000 total knee replacements (TKRs) are performed in Australia each year, but about 20% of patients continue to experience pain after surgery – and up to 24% have a serious adverse event.

“Unfortunately, patients won’t know if the benefits outweigh the risks until after they’ve had the surgery, so all they can do is look at the probabilities of each,” says Ian Harris, Professor of Orthopaedic Surgery at UNSW Sydney, who spearheaded a research project focused on improving patient selection for this kind of surgery.

“The risks for a healthy patient are less than for someone with a medical problem such as obesity or diabetes, but overall the risks of surgery remain reasonably low for everyone.”

But the benefits? They vary much more significantly. “Generally, the more severe the symptoms and disability associated with osteoarthritis, the greater the benefits [of surgery],” says Prof Harris.

For patients with mild symptoms who can still go about their daily activities without help, there isn’t much to be gained from a knee replacement, he explains. “In contrast, a patient with severe pain and disability can benefit greatly from knee replacement surgery while being exposed to the same risks, therefore greatly increasing the benefit-to-risk ratio.”

With a grant from the HCF Research Foundation, researchers at the University of Melbourne developed the SMART Choice tool to help patients assess how likely they are to benefit from a TKR. In a clinical trial, patients reported a reduced desire to have a TKR when the SMART Choice tool indicated a low likelihood of improvement after surgery. This tool has the potential to reduce the number of unnecessary surgeries, freeing up waitlists and reducing the burden on the healthcare system.

For those who aren’t good candidates for TKR or simply prefer to avoid it, several non-surgical interventions may help manage their symptoms.

“Exercise, walking aids and anti-inflammatory medication are commonly prescribed, but possibly the most effective non-surgical treatment is weight loss,” says Prof Harris. “Most patients undergoing [knee replacement] are obese, and studies have shown that weight loss in patients who need a knee replacement can significantly reduce their symptoms, often to the point where they no longer even need surgery.”

In line with these findings, the 2024 Osteoarthritis of the Knee Clinical Care Standard places a strong emphasis on empowering people with knee osteoarthritis to make lifestyle changes that will improve their condition. It also recommends that physicians avoid using language like “wear and tear” and “bone on bone”, making patients believe their joint health may be compromised by exercise – which isn’t the case.

Physical activity can effectively reduce the symptoms of knee osteoarthritis, and many experts believe early intervention is critical. A current trial funded by the HCF Research Foundation is investigating whether including an educational message about the benefits of exercise in knee osteoarthritis X-ray reports may help increase GP referrals to exercise professionals and improve outcomes for patients.

The benefits of short-stay knee replacement surgery

For patients who do choose knee replacement surgery, short-stay surgical models – which aim to discharge patients within 24 to 48 hours after surgery – are increasingly available in Australia.

“Specific protocols are used before, during and after surgery to improve patients’ comfort, enable them to be out of bed and walking early, and be ready to go home earlier,” says Professor Ilana Ackerman, from Monash University’s School of Public Health and Preventive Medicine.

Results have been promising so far: “Our systematic review of 49 studies from 16 countries found comparable safety outcomes after short-stay hip and knee replacement surgery compared to usual care, but further research is needed to determine whether short-stay programs are in fact safer.”

Implementing short-stay joint replacement programs widely across Australia would translate into important savings for the health system.

“Our modelling shows savings of an estimated $641 million and 337,000 acute hospital bed days between 2023 and 2030, with an overall return on investment of about $9 for every $1 spent. Some of these savings could potentially be reallocated to reduce costs for patients and to fund other services, such as helping patients get fit for surgery or rehabilitation services at home and in the community after surgery.”

Improving outcomes after knee replacement surgery

Following TKR, rates of inpatient rehabilitation have increased in Australia – even though it may not be necessary.

Often, the reason people prefer inpatient rehab is because they want their recovery to be closely supervised, but this doesn’t necessarily lead to better outcomes, says Professor Justine Naylor from UNSW Medicine & Health’s School of Clinical Medicine. “Several studies have shown that inpatient rehabilitation program outcomes aren’t superior to those of outpatient clinic or home programs.”

Patients who choose to recover at home after knee surgery typically report no significant differences in mobility, pain, function or quality of life. While inpatient rehab may be required for those who have other health issues or little support at home, for most patients, home-based programs are just as effective – and less costly.

Associate Professor Claire Ashton-James, Pain Management, at the University of Sydney School of Medicine, has helped develop an SMS text-messaging program to assist people in managing their pain after TKR surgery.

“Optimal acute pain management is achieved when medications are used in combination with behavioural pain management strategies,” she explains. “These include relaxation and breathing exercises, distraction, pacing activity, social interaction and support, and doing things that make you feel hopeful and happy.

“All these strategies are simple, cost-free and have been found to reduce pain and distress, but many patients aren’t aware of them or aren’t confident to use them. SMS text messages deliver daily reminders and hints for ways to self-manage pain as well as motivational support. The best part is that there are no risks associated with SMS support.”

With funding from the HCF Research Foundation, Assoc Prof Ashton-James and her colleagues are currently conducting a trial with Austin Health in Victoria to evaluate how easily and effectively their digital intervention for pain management can be implemented in tertiary hospitals (hospitals that focus on treating the most complex and severe medical conditions that require advanced medical and surgical interventions).

Looking after your joints

If you're getting knee pain or stiffness, we may be able to help. Eligible HCF members^* can access our Knee Osteoarthritis Program to help manage symptoms through lifestyle changes and exercises and potentially reducing the need for surgery. Delivered online or over the phone by HCF health coaches, the program offers personalised support, exercises to improve mobility and access to other health programs. Complete a 5-minute survey to check if you're eligible.