5 Osteoarthritis Myths, Busted

If you've been told you have osteoarthritis (OA), you've probably also been told a few things that aren't quite right. Here's what the current evidence says.

Myth 1: “Osteoarthritis is just wear and tear, and exercise will wear my joints out faster”

If OA were simply a mechanical wearing-out, the people who use their joints most would have the most OA. They don't.

A large meta-analysis found that only 3.5% of recreational runners developed hip or knee arthritis, compared with 10.2% of sedentary people.¹ Very high-level competitive runners had higher rates (13.3%), so there is a point where load and injury exposure matter. But for most of us, the real risk sits at the sedentary end. Among people who already have knee OA, runners did not have increased odds of worsening X-ray findings or new knee pain.²

OA is better understood as a whole-joint condition involving cartilage, bone, the joint lining and surrounding muscles. It is influenced by factors beyond load, including genetics, previous joint injury, body weight, low-grade systemic inflammation and age. Load is one piece of the picture.

Why movement is good for cartilage

Cartilage has no blood supply. It depends on synovial fluid diffusion for its nutrition. Think of it like a sponge. When you load the joint, fluid is squeezed out, carrying waste products with it. When you unload, fresh fluid carrying nutrients is drawn back in. Regular movement keeps that exchange going.

Cartilage cells respond to load as well. Moderate loading can maintain or even thicken cartilage, while too little loading causes it to thin, and excessive loading can damage it.³ That's a dose-response relationship, not a “load is bad” one. The practical message is to find the right amount, not to avoid load altogether. Clinical trials back this up: a Cochrane review pooling 32 trials found that exercise gave moderate improvements in pain and physical function.⁴

Myth 2: “OA is degenerative, so I'll just get worse over time”

“Degenerative” sounds like a one-way slide, but most people's symptoms don't follow it.

A systematic review of knee OA pain trajectories found that in the mid-term, 85% of people had a steady pain trajectory, 8% improved and 7% worsened.⁵ A large US cohort study found something similar: pain neither worsened nor improved on average over three years in most patients, and only 12.6% showed progressive worsening.⁶ Another review concluded that OA is a chronic condition that does not inevitably worsen in terms of patient-reported symptoms.⁷

What improves the odds

Exercise is a first-line treatment for OA in every major guideline.

Weight management matters for people carrying extra weight. In the IDEA trial, people who combined diet-induced weight loss with exercise had an average 51% reduction in pain, and the combination outperformed diet alone and exercise alone for pain and function.⁸

Myth 3: “If an activity hurts, it's damaging my joint”

Pain is not a reliable damage meter. It's an output of the nervous system that reflects the joint, but also sleep, stress, mood, past experiences and how much you've been doing lately. X-ray findings and pain are only loosely linked, and plenty of people with significant changes on imaging have little pain.

This is why we use a “sore but safe” approach. A rough traffic light guide, which your physio can tailor to you:

One caveat is that load can influence symptoms. In one diary study, physical exposures such as kneeling, squatting and heavy lifting were associated with roughly double the odds of a flare in the following 48 hours.⁹ So the aim is not to ignore pain, but to adjust the dose of activity and build capacity gradually.

Myth 4: “A flare-up means my OA is getting worse”

Flare-ups are a normal part of living with OA, not a sign your joint is deteriorating.

Researchers at Keele University used daily diaries to study knee OA flares. They suggest that nearly half of adults over 50 with knee OA may experience an acute flare. Flares were more likely to come with sharp or throbbing pain, swelling, limping, stiffness and night pain, and the median flare lasted 8 days. Most settle back to your usual baseline.^9,10

A flare tells you that your joint is irritated and your system is sensitive right now. It does not mean you've lost more cartilage. During a flare, keep moving gently, reduce (don't eliminate) your activity, use heat or your usual pain relief, and return to your normal routine as it settles. If flares are becoming more frequent or aren't settling, that's a good reason to book a review.

Myth 5: “OA is a one-way road to a joint replacement”

Most people with OA never need one, particularly with knees.

In Swedish register data on people referred for first-line OA care, 46% of those with hip OA and 20% of those with knee OA had progressed to joint replacement at five years.¹¹ In Denmark's GLA:D registry, 10% of the knee cohort and 30% of the hip cohort had a joint replacement over two years. The researchers concluded that a large proportion of people with OA do not seem to require surgery, especially those with knee OA.¹³

Early treatment response matters. Among people who had a meaningful pain improvement after a first-line program of education and exercise, 35% (hip) and 14% (knee) went on to surgery within five years, compared with 48% and 20% of non-responders.¹² These are observational data, so they show an association rather than proof that exercise prevents surgery. Joint replacement is an excellent option when conservative care isn't enough and your quality of life has been affected, but it's a choice you make, not an inevitability.

Hugo Dreux

Senior Physiotherapist · Move Physiotherapy

Hugo has a strong clinical interest in hip and knee osteoarthritis and runs Move's 8-week OA program. He trained at the University of Birmingham and spent over three years in the NHS, including as a Senior Physiotherapist, before joining Move.