Georgie Burgess
27 October 2025: It’s a surgery meant to alleviate people’s pain, but around one in five Australians who get a total knee replacement are still struggling with persistent pain for more than a year after their operations.
A team of researchers at the Â鶹´«Ã½, including Physiotherapy Honours student Marisa Herden, are determined to find out why so many continue to experience pain.
“20 per cent is a big portion of people who are still in pain after a surgery that is supposed to get rid of it, and it’s not really something that we should accept,” she said.
“And that number is only going to get bigger. If we look back to 2021, around 70,000 people were having a total knee replacement and that’s predicted to increase by over 200 per cent by the end of the decade.”
Alongside her supervisors, Ms Herden will use a mobile ultrasound to non-invasively track the tendons surrounding the joint, looking at changes three weeks before any operation, as well as six months afterwards.
“We’re looking at both the quadriceps and patella tendons. These tendons sit above and below your kneecap, and help to control the movement of the patella and keep it in place,” Ms Herden explained.
“Typically, in surgery they are not cut – but the patella, which is the bone attached to those tendons, is flipped upside down and moved to the side, so there’s a lot of stress placed on those tendons.”
Ms Herden hopes the project will shine a light on an under-researched area in a commonplace surgery.
“It’s something that tends to get pushed to the side a little, because during the surgical process, people are very focused on the bones and the prosthesis, and all those things that are happening inside the knee – but they aren’t really paying attention to the tendons, because they aren’t technically being operated on,” Ms Herden said.
“But it is something that we should be paying special attention to, because they are the only structures that aren’t being replaced during surgery, and there’s a good chance that they are responsible for patients’ pain.”
The search is now on for study participants over the age of 18, who are planning to undergo a total knee replacement in coming months.
“Participants will initially undergo a physical assessment here at UC, at which we will look at the range of motion in their knee, as well as working out where they are feeling any pain – after that we’ll use the ultrasound. All up, it takes about an hour - we then repeat the process again six months after the surgery,” Ms Herden said.
The team hopes that the research undertaken will improve rehabilitation protocols and the advice that is given to patients when accessing surgical care.
“We really want to make a difference, and I think it’s interesting how what is essentially just a small project in the larger research pathway can help build a larger impact and help change someone’s life for the better.”
Keen to take part or find out more? Contact Marisa at u3253130@uni.canberra.edu.au.