Weight-loss drugs may prevent thousands of knee replacements, study suggests

Being overweight or obese significantly increases the risk of developing knee arthritis, by placing greater load on the joints. Photograph: Portra/Getty Images View image in fullscreen Being overweight or obese significantly increases the risk of developing knee arthritis, by placing greater load on the joints. Photograph: Portra/Getty Images Weight-loss drugs may prevent thousands of knee replacements, study suggests Patients with knee arthritis who took medications for at least three years at reduced risk of needing surgery Taking weight-loss drugs for at least three years could prevent thousands of knee replacements a year, research suggests. Globally, more than 500 million people have osteoarthritis. Knee arthritis is the most common form, affecting about 14 million people in the US and more than 5 million in the UK . Many will require knee surgery. In the UK more than 120,000 knee replacements are carried out every year. Being overweight or obese significantly increases the risk of developing knee arthritis, by placing greater load on the joints. Previous studies have found that weight-loss drugs can help reduce the pain from knee osteoarthritis. Now researchers have found that taking medications such as Mounjaro and Wegovy, or those for type 2 diabetes such as Ozempic, could also help prevent the need for knee surgery. Experts at the University of Maryland School of Medicine in the US examined data for 6.8 million adults diagnosed with knee osteoarthritis between 2010 and 2024. They then identified a matched sample of 42,000 people who had been taking any type of GLP-1 medication for at least one year, who were compared with an equal number of similar patients who had not. They also analysed data for just under 31,000 patients who had been taking the drugs for three years. Patients were tracked at regular intervals for eight years after diagnosis to assess the need for knee replacement surgery. The study, published in Regional Anesthesia & Pain Medicine, found that taking GLP-1 medications for one year was associated with a 1.4-percentage-point reduced risk of knee replacement surgery at the three-year follow-up point and a 2.8-percentage-point lower risk after eight years. But the greatest reduction in risk was with newer weight-loss drugs and longer treatment. Taking semaglutide or tirzepatide for three years was associated with a nearly 5-percentage-point lower chance of needing knee replacement at the eight-year follow-up assessment. The authors speculated that, if all eligible patients with knee arthritis and obesity or metabolic disease took semaglutide or tirzepatide for three years, there could be up to 14,400 fewer knee replacements every year in the US and more than 1,500 a year fewer in the UK. “Our findings align with evidence that GLP-1 [receptor agonists] may influence knee [osteoarthritis] through complementary anti-inflammatory and analgesic mechanisms,” they conclude. Responding to the findings, Mark Bowditch, a consultant