What the Billion-Case Osteoarthritis Warning Means for Aching Knees
The billion-case forecast is three years old. What is new is a Lancet verdict on care, and the evidence on what helps a painful knee in your 50s or 60s.
The number leading Monday's osteoarthritis headlines, almost one billion people living with the disease by 2050, is three years old. It first appeared on Aug. 21, 2023, in a Global Burden of Disease paper in The Lancet Rheumatology. The new part is a charge aimed at health systems rather than drug laboratories: that osteoarthritis is "inconsistently and often inappropriately treated and prevented."
If your knee complains on the stairs, that charge matters more than the forecast. It means effective care exists and too often is not reaching you.
On Monday, Oct. 12, 2026, the roadmap published in The Lancet, led by Curtin University's Andrew Briggs, said about 600 million people had osteoarthritis in 2023 and almost one billion may by 2050, with no drug that can stop or slow the disease. For a painful knee, the evidence points to therapeutic exercise and weight loss, not knee scopes, glucosamine or routine scans.
An old forecast, a new charge
Briggs wrote the paper with experts from 18 countries, with Professor Lyn March of the Kolling Institute and Professor David Hunter of the University of Sydney as co-senior authors. It asks governments for three things:
- Recognise the disease, with national data on its burden and cost.
- Scale up affordable, person-centred care within primary and chronic disease services.
- Slow its growth by targeting excess body weight and joint injury, including at work and in sport.
"The global disability burden attributed to osteoarthritis has increased by 65 per cent between 1990 and 2023 – one of the largest increases amongst the more than 350 different conditions tracked in the Global Burden of Disease study."
Professor Lyn March, co-senior author, Kolling Institute and Global Alliance for Musculoskeletal Health
Headcounts differ. The World Health Organization says about 528 million people had osteoarthritis in 2019; a 2023 Global Burden of Disease analysis says 595 million in 2020; the roadmap says about 600 million in 2023. Different modelling rounds, same direction.
Mostly more people, living longer
Almost one billion would mean roughly 400 million more people with the disease, a rise of about two-thirds.
Between 1990 and 2020, total cases rose 132.2%. Over the same years, the age-standardised disability rate rose only 9.5%. Most of the growth comes from more people living longer; the age-adjusted rate rose far less.
High body mass index accounted for an estimated 20.4% of the osteoarthritis burden, about one in five, with wide uncertainty: the interval runs from −1.7% to 36.6%, crossing zero. Joint injuries "have not yet been explored in GBD modelling", and Briggs singled out anterior cruciate ligament (ACL) injuries in Australia as a clear target for prevention.
The knee dominates. The WHO counted 365 million knee cases in 2019, more than two in three.
Eleven drug candidates, no approvals
The missing medicine is a DMOAD, a disease-modifying osteoarthritis drug that slows, halts or reverses joint damage.
A 2025 review in Biomedicines of trials from 2010 to 2024 examined 11 candidates. Six showed a statistically significant structural or symptomatic benefit without major safety concerns. None is approved.
"Most cases of OA progress slowly and are treated over decades, but a majority of clinical trials have primary endpoints between 6 and 24 months," the authors write. Pain is "highly subjective and susceptible to the placebo effect", and its link to joint structure "is not always linear".
Pain relief can even backfire. Tanezumab, a nerve growth factor blocker from Pfizer and Eli Lilly, carried a risk of "rapidly progressing osteoarthritis". In March 2021, two FDA advisory committees voted 19-1 that the risk was too great.
"There is an unmet need for efficacious treatment of osteoarthritis ... Unfortunately, however, this drug, tanezumab does not fulfill this need."
Edward Y. Cheng, MD, University of Minnesota Medical School, FDA advisory committee member, quoted by Healio
Promising work exists, though one cartilage-regrowth approach has so far worked only in mice, and sprifermin, which did thicken cartilage slightly in people, brought no pain benefit. Plan as if no pill is coming soon.
What the trials support for a painful knee
Under England's NICE guideline on osteoarthritis, published Oct. 19, 2022, anyone 45 or over with activity-related joint pain and morning stiffness of 30 minutes or less can be diagnosed without imaging. Core treatment is exercise and weight management.
A 2015 Cochrane review pooled 44 trials with 3,537 participants: land-based exercise cut knee pain by 12 points on a 0–100 scale, from 44 in control groups, about a 27% reduction. The authors called it "comparable with estimates reported for non-steroidal anti-inflammatory drugs."
The catch is durability. Two to six months after programs ended, the pain benefit had halved to 6 points. Exercise behaves like a dose, not a course, so a tailored program from a GP or physiotherapist is something to keep doing. NICE says to expect some extra pain at first.
On weight, NICE says "any amount of weight loss is likely to be beneficial, but losing 10% of their body weight is likely to be better than 5%." The STEP 9 trial, published Oct. 31, 2024, gave 407 people with obesity and knee osteoarthritis, mean age 56, weekly semaglutide 2.4 mg or placebo for 68 weeks, with diet and activity counselling for all. The drug group lost 13.7% of body weight against 3.2%, and their pain score fell 41.7 points against 27.5.
Semaglutide beat placebo by 14.2 points, while the placebo group, which also got counselling, improved by 27.5. Participants had a mean BMI of 40.3 and 81.6% were women; Novo Nordisk funded the trial; side effects led 6.7% to stop against 3.0%. It showed less pain alongside weight loss; it did not test whether the joint itself changed. Access, complicated by the end of compounded semaglutide, is a question for your doctor.
"Although there are currently no disease-modifying drugs for osteoarthritis, we do know there are effective ways to help people manage osteoarthritis, but too many people are still receiving care that does not reflect the best available evidence."
Professor David Hunter, co-senior author, University of Sydney, in a statement released by Curtin University
Scopes, supplements and scans that fail the test
Knee arthroscopy for degenerative disease is "performed more than two million times each year" worldwide, a 2017 BMJ panel noted, issuing "a strong recommendation against" it because "there is evidence of harm and no evidence of important lasting benefit in any subgroup." NICE agrees.
NICE says do not offer glucosamine, and do not routinely offer paracetamol, as "there is no strong evidence of benefit." It recommends a topical anti-inflammatory for the knee, notes steroid injections give 2 to 10 weeks of relief, and advises against routine scans.
| Option for knee osteoarthritis | What the evidence says | Source |
|---|---|---|
| Therapeutic exercise | Pain down about 12 points on a 0–100 scale; function up about 10 | Cochrane review, 44 trials |
| Weight loss | If overweight: any loss likely helps; 10% likely better than 5% | NICE NG226 |
| Semaglutide 2.4 mg weekly (people with obesity) | Pain down 41.7 points vs 27.5 on placebo over 68 weeks | STEP 9, NEJM 2024 |
| Topical NSAID | Offer for knee osteoarthritis | NICE NG226 |
| Steroid injection | Short-term relief, 2 to 10 weeks | NICE NG226 |
| Paracetamol | No strong evidence of benefit; not routinely offered | NICE NG226 |
| Glucosamine | Do not offer | NICE NG226 |
| Arthroscopy (washout, debridement) | Strong recommendation against; no lasting benefit in any subgroup | BMJ panel 2017; NICE NG226 |
For late disease, joint replacement remains "highly effective for late stage osteoarthritis in hips and knees," the 2023 burden paper says. The aim is fewer people needing it.
The care gap behind the numbers
The roadmap cites Australia's CareTrack study: only 43% of osteoarthritis care encounters met best-practice standards in 2009-10. A 2018 review led by Ivan Lin found Aboriginal people get osteoarthritis at similar or higher rates than other Australians but use primary care for hip and knee osteoarthritis at about half the rate.
Language matters too. "Descriptions like 'bone on bone' or 'wear and tear' are outdated and often drive disengagement in care," Hunter said. Professor George Milne of the University of Western Australia, who lives with the disease, said: "There are days when something as simple as walking, exercising or doing the things you normally enjoy can become much harder because of pain."
"Osteoarthritis faces an image problem – it's perceived and dismissed in communities as an unavoidable part of ageing with limited management options, it is not integrated into service models for chronic diseases, and remains largely invisible in national health policies."
Professor Andrew Briggs, lead author, Curtin University School of Allied Health
That is the real failure in Monday's paper. The knee treatment with the strongest evidence, and no serious harms reported in its trials, needs no new drug at all. It is also, by the roadmap authors' own account, the kind of care too many people still don't receive. No drug in the pipeline changes that arithmetic.
