Study suggests weight-loss drugs could reduce knee replacements
A study published in Regional Anesthesia & Pain Medicine suggests that taking weight-loss drugs for at least three years could prevent thousands of knee replacements each year. Researchers at the University of Maryland School of Medicine analyzed data from 6.8 million adults diagnosed with knee osteoarthritis between 2010 and 2024. They compared matched samples of 42,000 patients who took any GLP-1 medication for at least one year with an equal number who did not, and also examined data from nearly 31,000 patients who took the drugs for three years. Patients were tracked for eight years after diagnosis. The study found that taking GLP-1 medications for one year was associated with a reduced risk of knee replacement surgery at both three-year and eight-year follow-up points, with the greatest risk reduction seen in those taking semaglutide or tirzepatide for three years. Responding to the findings, medical experts cautioned that the drugs are not approved for osteoarthritis and that the study does not prove the drugs prevent the need for surgery. The authors estimate that if all eligible patients took these drugs for three years, there could be up to 14,400 fewer knee replacements annually in the US and more than 1,500 fewer in the UK.
What’s reported
The study examined data on 6.8 million adults diagnosed with knee osteoarthritis between 2010 and 2024.
Researchers used a matched sample of 42,000 patients who took any GLP-1 medication for at least one year, compared to the same number who did not, plus nearly 31,000 who took the drugs for three years.
Patients were tracked at regular intervals for eight years after diagnosis.
One year of GLP-1 use was associated with a 1.4-percentage-point reduced risk of knee replacement at three-year follow-up and a 2.8-percentage-point lower risk at eight years.
Three years of semaglutide or tirzepatide was associated with a nearly 5-percentage-point lower chance of needing knee replacement at the eight-year follow-up.
The authors project up to 14,400 fewer knee replacements yearly in the US and more than 1,500 fewer in the UK if all eligible patients took these drugs for three years.
The study was published in the journal Regional Anesthesia & Pain Medicine.
Conflicting accounts
No direct conflicting accounts are reported in the source article, but expert responses varied. Consultant knee surgeon Mark Bowditch said the findings do not prove the drugs prevent surgery and urged caution against using GLP-1 receptor agonists for osteoarthritis outside clinical trials. Prof Lucy Donaldson of Arthritis UK said the findings could help understand the potential impact of weight-loss medications to help some patients avoid or delay joint replacement.
Open questions
Whether the observed reduced risk of knee replacement is directly caused by the drugs or is due to weight loss or other factors remains unproven, according to experts cited in the article.
Key figures
Mark Bowditch – consultant knee surgeon and immediate past president of the British Orthopaedic Association
Prof Lucy Donaldson – director of research at Arthritis UK
Researchers at the University of Maryland School of Medicine (not individually named in the article)
Sources: The Guardian
