As serious complications mount, so do calls for the industry driven treatment to be abandoned.
Hyaluronic acid injections, often promoted as a lubricant for arthritic knees, are drawing renewed concern from specialists as hospitals report a rise in severe infections linked to the treatment.
Rheumatologists and orthopaedic surgeons say they are increasingly seeing avoidable cases of septic arthritis in patients who received the injections at radiology clinics, even though evidence shows the therapy offers no meaningful relief for osteoarthritis and carries avoidable risks.
Hyaluronic acid is most commonly used in beauty products to hydrate the skin. However, they are promoted patients with joint pain caused by arthritis under the theory that the acid lubricates the joint and eases pain.
Intra-articular hyaluronic acid, also known as viscosupplementation, has been a controversial topic since the first clinical trial in the 1970s.
Speaking to The Sydney Morning Herald last week, orthopaedic surgeon Dr Ian Harris said it was a concern.
“We’re seeing a string of patients who have turned up in the emergency department of our hospital with infected knees, that have needed surgery and IV antibiotics,” he said.
“Rather than relieving their osteoarthritis – which is what the injections are purportedly for – they are making the patient worse by causing an infection.”
Rheumatologist, University of Sydney clinical researcher, and Arthritis Australia’s scientific advisory panel member Professor David Hunter told the SMH that while the injections were not supported by robust evidence, they were attractive to patients who wanted a quick fix.
He said he regularly came across adverse reactions caused by the injections and estimated about five to 10% of patients would present with significant swelling in their knee following the injections.
“The injection has proteins that are often derived from a rooster’s comb, so the avian proteins cause a local reaction in the human because we’re not used to having bird protein in our body,” he said.
“It can be very painful.”
Vice-president of the Australian Rheumatology Association Dr Helen Keen told Rheumatology Republic the practice had been examined in a 2022 BMJ systematic review and meta-analysis of randomised trials.
“The BMJ systemic review of 2022 really suggests there’s not likely benefit from this, so patients shouldn’t be offered this procedure, especially when it’s associated with risks and radiation exposure,” she said.
As part of the BMJ review, searches were conducted of Medline, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL) databases from inception to 11 September 2021. Unpublished trials were identified from the grey literature and trial registries.
In total, 169 trials provided data on 21,163 randomised participants. Evidence of small study effects and publication biases was observed for pain and function (Egger’s tests with P<0.001 and asymmetric funnel plots).
Twenty-four large, placebo controlled trials (8997 randomised participants) included in the main analysis of pain indicated that viscosupplementation was associated with a small reduction in pain intensity compared with placebo (SMD −0.08, 95% confidence interval −0.15 to −0.02), with the lower bound of the 95% confidence interval excluding the minimal clinically important between group difference.
This effect corresponded to a difference in pain scores of −2.0 mm (95% confidence interval −3.8 to −0.5 mm) on a 100 mm visual analogue scale. Trial sequential analysis for pain indicated that since 2009 there has been conclusive evidence of clinical equivalence between viscosupplementation and placebo.
Similar conclusions were obtained for function. Based on 15 large, placebo-controlled trials on 6462 randomised participants, viscosupplementation was associated with a statistically significant higher risk of serious adverse events than placebo (relative risk 1.49, 95% confidence interval 1.12 to 1.98).
“Strong conclusive evidence indicates that viscosupplementation leads to a small reduction in knee osteoarthritis pain compared with placebo, but the difference is less than the minimal clinically important between group difference,” the researchers concluded.
“Strong conclusive evidence indicates that viscosupplementation is also associated with an increased risk of serious adverse events compared with placebo. The findings do not support broad use of viscosupplementation for the treatment of knee osteoarthritis.”
Dr Keen said the potential complications from the procedure should not be underestimated.
“They involve a hospital stay, antibiotics through a drip, and almost certainly an operation, and then damage done to the knee, and that’s not all,” she told RR.
“The other big side effect is this inflammatory arthritis, which can look very much like an infection anyway.
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“It’s not uncommon to have an inflammatory action to the hyaluronic acid and it will present in the same way, and you’ll often end up in hospital having the same investigations done as if it was an infection, because that’s obviously a risk as well.”
Dr Keen said this was clearly “a treatment driven by industry”.
“There’s companies with money to be made by selling this product and they continue to advertise its benefits,” she said.
“Research continues to be done when we have high quality evidence that it really doesn’t help. So we shouldn’t invest in any more research in this product, and we and we shouldn’t be giving this product to our patients.”
The Royal Australian College of General Practitioners and Arthritis Australia strongly advise against the treatment.
The Therapeutic Goods Administration recorded two cases of infection linked to the injections last year, though actual numbers were likely higher given that only an estimated 0.5% of adverse events were reported.
While hyaluronic acid injections are not covered by Medicare, several radiology practices have been bulk-billing them, often pairing the procedure with CT guidance, which attracts a substantial Medicare rebate.
According to the TGA’s Database of Adverse Event Notifications, there were 44 adverse reports relating to synovial fluid supplementation substance between 1 January 2015 and 4 September 2025.
A TGA spokesperson told Rheumatology Republic that “based on the data available, the TGA has not identified a recent spike in reports of adverse reactions for this category of devices.
“The TGA is not considering regulatory actions in relation to these types of medical devices at this time, but if any new clinical evidence about these products becomes available, the TGA would evaluate and consider that evidence appropriately,” he said.
“Decisions about the use of these products should be determined by the treating health professional in line with accepted medical practice and careful patient selection, taking into account other available management options.
“The TGA does not regulate clinical practice of treating health professionals.”
