How to prevent knee injuries

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Allyson Jackson is 31, but there’s a good chance your granny could beat her up the stairs.

Years of sport, followed by weight gain, stressed her joints until they needed surgery. Now she ices her knees up to six times a day. Jackson’s story is part of a growing trend: osteoarthritis (OA), a progressive joint disease, is striking young women, most commonly in the knees.

The reason behind our rise in dodgy knees is clear: we love sport. And women are playing netball, basketball, hockey and soccer way more than say, 50 years ago. “Jumping and landing even a tiny bit off balance can cause twisting of the knee, which can lead to cartilage or ligament injuries that can sideline you for months or even years,” says Professor Peter Choong, president of the Australian Orthopaedic Association.

And weekend warriors are seeing the same cartilage-crushing effects from fitness routines overloaded with repetitive motion – like using the stair-climber or logging kays on the treadmill. What’s more: a report by Arthritis and Osteoporosis Victoria found the prevalence of OA in women aged 25-34 was more than double that of blokes.

What gives? For one, biology. Hormones can make women’s joints more susceptible to damage. Research by the University of Texas found knee muscles work differently at different points in your menstrual cycle which can destabilise the joints and set them up for injury.

Gender variations in the nervous system may also play a role: scientists at Oregon State University found men’s muscles respond to nerve impulses at a much faster rate than women’s, a difference that suggests female muscles may be less likely to react efficiently during crucial moments.

Then there’s the fact that men simply move differently. According to research in the Journal of Athletic Training, women tend to land knock-kneed from jumps, with one knee pointing towards the other, potentially putting the anterior cruciate ligament (ACL) – which is crucial for stabilising the knee – in danger of tearing off. Ouch.

Cartilage connection

Those ACL injuries aren’t just causing painful short-term damage. More than half of women with this injury will end up with OA, most likely within 10 years (see below). Also damaging – and common – are injuries to the meniscus, the shock-absorber-like cartilage that cushions your knee.

“Badly injuring the meniscus significantly increases your odds of developing OA, as some meniscus injuries can’t heal, so they get worse over time,” explains Dr David Wood, orthopaedic surgeon and president of the Australian Orthopaedic Association’s Australian Knee Society. Being off balance during a simple task like squatting to pick something up can cause a tear, even in a healthy woman with no prior knee injury.

Knee savers

Though you can’t entirely ward off OA (cartilage naturally breaks down as we age), you can keep it at bay by giving your knees a little TLC. Obesity is a big OA risk factor, so keeping a healthy weight is key – as little as an extra 5kg will add strain to the joint. Lighting up is also a no-no, as ingredients in cigarettes may harm cells that keep cartilage healthy. And a study by Iowa State University found high heels (as little as 5cm) may also stress joints if worn constantly because they alter the way you walk, putting extra force on the inside of the knee.

Worried you’ve already damaged your joints? Mild or moderate pain that comes and goes with exercise is common, but if you regularly feel the same pain in the same part of the knee for more than three weeks and it doesn’t respond to non-steroidal anti-inflammatory drugs, a reduced exercise regimen or ice, it’s time to get your knee seen by a specialist.

Swelling, clicking, popping, dull throbbing in cold weather, or feeling that the knee is unsteady, are signs that something could be wrong. Injections that stop inflammation and replace joint fluid can help ease pain; and on the horizon are treatments with lab-grown cartilage transplants, which researchers are studying in the hope of fixing small defects – like filling potholes – but they’re still in the experimental phase and don’t come cheap.

In the meantime, a knee-friendly fitness plan with plenty of variety can keep wear and tear to a minimum (see below). Cross-training and aerobic fitness improve coordination and balance, making stacks less likely; jumps and modified squats boost core strength, which stabilises your knees and prevents that knock-kneed collapse on landings. Low-impact workouts on a stationary bike or cross-trainer build leg muscles while going easy on the joints.

“Muscle mass and strength around the knee can give you better joint longevity, because strong muscles share more of the load,” says Wood. The time and sweat you put into keeping your knees healthy will help you get – and stay – pain-free. Amen to that.

A slow-moving setback

Month 1 Once cartilage has been damaged, knee cells become inflamed.

Months 1-6 Without treatment, the inflammation spreads, and cartilage directly around the site of the injury starts
breaking down.

Year 1 Damage spreads to nearby healthy cartilage, like ripples across a pond.

Year 2 You could still be pain-free, but the immune proteins have started to break down the sturdy framework that holds your knee together. An MRI could pick up early changes in cartilage and bone, called pre-osteoarthritis.

Years 5-10 Cartilage can no longer work as a shock absorber, leaving bones rubbing together and causing joint-damaging bone spurs. What began years ago as a tiny chink in cartilage is now full-blown OA, what doctors call end-stage joint disease. Your only option is a complete joint replacement. Oh.