Taking weight-loss drugs for at least three years could prevent thousands of knee replacements annually, according to a new study. Researchers at the University of Maryland School of Medicine analysed data from 6.8 million adults with knee osteoarthritis, finding that those on GLP-1 medications such as semaglutide or tirzepatide had a lower risk of needing knee surgery.
The study, published in Regional Anesthesia & Pain Medicine, examined 42,000 patients who took GLP-1 drugs for at least one year and nearly 31,000 who took them for three years. After eight years of follow-up, those on the newer weight-loss drugs for three years had a nearly 5-percentage-point lower chance of requiring knee replacement.
If all eligible patients with knee arthritis and obesity took these drugs for three years, the authors estimate up to 14,400 fewer knee replacements per year in the US and over 1,500 fewer in the UK. The drugs may work through anti-inflammatory and analgesic mechanisms beyond weight loss.
However, experts urge caution. Mark Bowditch, a consultant knee surgeon, noted potential direct anti-inflammatory effects but stressed the drugs are not approved for osteoarthritis. Prof Lucy Donaldson of Arthritis UK said the findings help understand the potential impact of weight-loss medications on joint surgery, while emphasising that maintaining a healthy weight remains key.
