Hyaluronic acid injections do not help knee osteoarthritis, study finds

A The commonly used treatment for people with knee osteoarthritis is only marginally more effective than the placebo effect in reducing pain and improving function, according to a new review of 50 years of data. Yet despite decades of mounting evidence showing that hyaluronic acid injections don’t help most patients with osteoarthritis, the injections have become more widely used, costing the US healthcare system more than $300 million every year. year. in health insurance claims only.

Osteoarthritis is a chronic, incurable disease that occurs when cartilage breaks down in the knees, hips, hands, or other joints, leading to pain, limited range of motion, and swelling. More than 32 million adults in the United States suffer from osteoarthritis, according to estimates from the Centers for Disease Control and Prevention. Since there is no cure, people with osteoarthritis often manage their condition with exercise, physical therapy, medications, and injection therapies. Since the 1970s, hyaluronic acid has been one of these injectables.

Originally sourced from the fiery red fleshy crown cartilage at the top of a rooster’s head, the treatment has been dubbed ‘the rooster comb injection’ and is believed to offer a gelatinous cushion for worn joints. In 2018, it was given as first treatment to around one in seven patients with osteoarthritis knee pain, according to an article published in the medical journal BMJ Wednesday.


This broad look at the scientific literature concluded that injection of hyaluronic acid – called viscosupplementation – offers such a small reduction in pain and stiffness in osteoarthritis of the knee compared to placebo injections that it does not significant difference in the lives of patients. Additionally, the injections were also linked to an increased risk of experiencing a wide range of negative side effects, according to the journal.

Lead author Bruno da Costa, a physical therapist, has been following the trajectory of hyaluronic acid injections for over a decade. In 2012, he and a team of researchers published a similar review in the Annals of Internal Medicine showing that viscosupplementation had very little, if any, effect on knee osteoarthritis compared to placebo. The therapy is the most studied joint injection in the field, and yet no rigorous study has shown significant benefit for patients, he said. “We already have enough trials to come to a conclusion. We don’t need more.


Yet even after this 2012 article was published, the rate of new trials per year doubled to eight per year. Between 2009 and 2021, “more than 12,000 patients were subjected to intra-articular injections in viscosupplementation trials, raising ethical concerns,” the BMJ article states.

These trends prompted da Costa to conduct an updated and broader systematic review of hyaluronic acid studies. His team at the Li Ka Shing Knowledge Institute at St Michael’s Hospital in Toronto scoured international search databases to find 169 randomized trials that met their criteria. A total of 21,163 participants were involved. The researchers then focused on a few dozen large placebo-controlled trials, with more than 6,000 participants in total, to analyze reported changes in pain intensity, levels of function and risk of adverse events.

The results confirm what da Costa and others have claimed for years: hyaluronic acid injections offer negligible improvements while possibly increasing the risk of serious side effects. Some studies have reported gastrointestinal inflammation and infections, cardiovascular problems, blurred vision, and dizziness, among other problems, in patients receiving hyaluronic acid, although the authors dismissed these as not being related to injections. In 2018, more than a quarter of Medicare spending on viscosupplementation was incurred for the treatment of subsequent joint infections, the paper says. Since people who take part in trials tend to be healthier than the general population, these risks could be even more pronounced in real-world settings.

Chronic illness can be a journey of desperation, making floating debris look like a life raft. Faced with progressively worsening osteoarthritis, patients and doctors often look for tools that could help avoid surgery. Along the way, many encounter through word of mouth, seemingly legitimate health websites, or heavy marketing, a slew of supplements and therapies backed by little or no unbiased scientific evidence.

Paul von Hippel, a statistician, scoured research on collagen supplements when he began to develop osteoarthritis of the knee in his early 50s. A professor at the Center for Health and Social Policy at the University of Texas, Austin, von Hippel decided to try collagen after hyaluronic acid offered no lasting pain relief (he wrote about his experience in a STAT First Opinion article). “I didn’t think it helped me, and the BMJ article came to a similar conclusion,” he told STAT in an email. The average effect of hyaluronic acid injections is around 2 points on a pain scale that ranges from 1 to 100.

Part of the difficulty for patients is that industry-sponsored research abounds and can skew the data to paint a picture of the success of products that won’t reduce their symptoms. While some unproven products, like some vitamin supplements, are relatively benign and affordable, viscosupplementation can cost thousands of dollars and pose real risks, leading to a different calculation, said Cara Cipriano, associate professor of adult reconstruction at the Perelman School of Medicine at the University of Pennsylvania. “So I think it becomes problematic,” she said.

In a 2016 study of patients with knee osteoarthritis treated with hyaluronic acid, patients received an average of 3.6 injections at an average cost of more than $300 per injection. The result is a large sum of money, sometimes paid out of pocket, sometimes covered by health insurance or insurers, for questionable treatment. This financial incentive could encourage continued use, she said.

“This is not the first attempt to examine the value of viscosupplementation. And there are other organizations and groups that have done very thorough reviews of the literature and have basically come to very similar conclusions,” said Cipriano, chief of orthopedic oncology at Penn Medicine. The American Academy of Orthopedic Surgeons published clinical guidelines in 2013 and doubled in 2016advising against the use of hyaluronic acid injections for patients with knee osteoarthritis.

Abundant evidence shows that viscosupplementation fails to relieve symptoms in people with advanced knee osteoarthritis and should not be used as a first treatment (topical therapies have shown more promise), but more research is needed to determine if hyaluronic acid might help certain patient subgroups. , the researchers told STAT.