Of all the lower body joints, the knee is probably the one most likely to send you to the physiotherapist.
“It carries most of the weight of the body, and being a hinge joint, it means that it doesn’t have a nice socket structure,” says physiotherapist Dr Jillian Eyles, from the University of Sydney. “It relies on the ligaments and the joint capsules and the muscles around it to really stabilise the joint, and it’s fairly easy to injure compared to another joint that’s more supported.”
Knee injuries, and the associated increase in the risk of developing knee osteoarthritis, are a key reason why more than 53,000 knee replacement surgeries are performed each year in Australia, and that figure is expected to more than double by 2030.
Here’s what experts say about how to keep your knees healthy and avoid becoming one of those surgical patients:
Avoid injury
Knee injury substantially increases the risk of knee osteoarthritis, and at a younger age. One of the most common serious knee injuries is a tear of the anterior cruciate ligament, which crosses diagonally under the kneecap and connects the thigh bone to the shin bone – the same injury that took Matildas star striker Sam Kerr out of the game for over a year.
It is possible to reduce the risk of knee injuries like this by warming up properly before activity, says physiotherapist Dr Kathryn Mills, from Kensington Physiotherapy and Macquarie University in Sydney. “That’s not going for a run and stretch – it’s doing a designed program that is designed to train both how your muscles are working, the extent to which they’re working, and how your brain is turning on those muscles,” she says.
Warm-up activities recommended for preventing ACL injuries include squats, walking lunges, running with high knees, and side-to-side jumps and hops.
Maintain healthy weight
The knee is one of the key load-bearing joints of the body, so the greater the load on that joint, the greater the risk of damage over its lifespan. “If you think about how many steps a day someone walks, [that] accumulates over the course of their life, if you’re putting a lot of load on those joints – which can come from body weight – that can be a contributor,” says Prof Rana Hinman, a research physiotherapist at the University of Melbourne. She recommends maintaining a healthy weight for healthy knee joints, both to reduce load and reduce inflammation.
There’s also strong evidence that in people who are overweight and have knee pain, losing just a small percentage of body weight can significantly reduce their pain and osteoarthritis symptoms, Eyles says.
Keep active
One of the best ways to keep the knees healthy is to keep them moving, says Natalie Collins, an APA sports & exercise physiotherapist and associate professor at the University of Queensland. She advises about 150 minutes of at least moderate physical activity each week, “but also really importantly, building in some resistance training as well, twice a week, where you’re really getting your muscles to have the capacity to do all of the things you need to do in your day, like squat down, go up and down stairs, maybe play sport or run,” Collins says.
Warming up properly, doing exercises such as leg curls and gradually introducing higher levels of activity over time can help keep your knees in good condition. Photograph: Oranuch Binmohamet/Alamy
Simple exercises like doing squats or lunges, or standing up from a chair repeatedly are good starting points. If you do have access to gym equipment, she recommends leg extensions – where you straighten your leg from a bent position with the weight on top of your ankle – or leg curls where you lie face down and bend your lower leg up against a weight or resistance band, both of which work the quad and hamstring muscles.
Ease into activity
During Covid lockdowns, many people dealt with cabin fever and gym closures by enthusiastically taking up a new outdoor activity such as running. And while activity is encouraged, it should be introduced in a gradual fashion, says physiotherapist Dr Michael O’Brien, from La Trobe University in Melbourne.
“Everyone just got into running or walking, and just did a lot of it very quickly, and ran into a lot of problems in terms of sudden onset of pain doing a lot of an activity that they were not accustomed to,” he says.
The key is to expose the body – especially the joints – to that load gradually. “If you want to run a marathon, you don’t decide three weeks beforehand and then just go out and do it,” he says.
Mills suggests gradually building up your level of activity. “Start off really small, and every week you can increase by somewhere between about 10% [and] 30%,” she says. “You’ll get to where you want to go and more importantly, you’ll make a consistent improvement.”
