Weight loss medication may help some people reduce the need for a knee replacement, a new study suggests.
Knee replacements are one of the most common pre-planned operations, with more than 790,000 total knee replacements performed each year in the Us and 110,000 in the UK.
But new research suggests a number of these surgeries could be avoided among patients with osteoarthritis if they take weight loss drugs.
Researchers, led by experts from the University of Maryland School of Medicine in the US, wanted to examine the use of glucagon-like peptide 1 receptor agonists (GLP-1s), such as Mounjaro, Ozempic and Wegovy, which are used to treat type 2 diabetes and obesity.
They said that use of these drugs has been linked to reductions in knee osteoarthritis pain, but studies have not yet looked into whether or not use of the drugs has been linked to reduced risk of knee replacement surgery.
The team examined information from a global database on patients diagnosed with knee osteoarthritis between 2010 and 2024.
They also looked at whether or not these patients were taking, or had taken, GLP-1 drugs.
This information was compared to the need for total knee replacement surgery, which was assessed at one year, three years, five years and eight years after diagnosis.
Researchers found that there was a “significantly lower incidence” of total knee replacements among people who took GLP-1s.
The effects appeared to be stronger when people took the treatments for a longer period, and among those who took newer versions of the drugs, like semaglutide (such as Ozempic or Wegovy) or tirzepatide (Mounjaro).
The researchers estimated that, if patients took newer GLP-1s for three years, a one year “absolute risk reduction of 1.44%” would lead to 14,400 fewer knee replacements every year in the US alone.
They said that the findings suggest “potential disease modifying activity beyond weight loss alone” but the findings need to be confirmed in trials.
“These findings suggest that GLP- 1 RAs, particularly newer agents used over sustained durations, may represent a meaningful complementary strategy within non- surgical knee OA management for eligible patients with concurrent obesity or metabolic disease,” they wrote in the journal Regional Anesthesia and Pain Medicine.
“In this large, multicentre, real-world cohort study, GLP- 1 RA use was associated with a significantly reduced long term risk of TKA (total knee arthroplasty) in patients with knee OA, with effects that were greater with longer treatment duration and newer generation agents.
“These duration and agent dependent associations are consistent with potential disease modifying activity beyond weight loss alone, although prospective trials are needed to establish causality and define optimal treatment targets.”
Commenting on the study, Professor Lucy Donaldson, director of research at Arthritis UK, said the study was "encouraging" as it suggests that people with knee osteoarthritis who are taking weight loss medications are less likely to need knee replacement surgery, compared to those not taking these medicines.
“Maintaining a healthy weight can play a vital role in managing osteoarthritis, particularly in weight-bearing joints such as the knees and hips. However, we know arthritis can lead to difficulties in staying mobile and active,” she said.
“For those able, even a small amount of weight loss can improve symptoms and sometimes slow the progression of OA. Research like this is helping us better understand the potential impact of weight loss medications, including whether they could help some people with osteoarthritis avoid or delay the need for joint replacement surgery.”
