Treating knee osteoarthritis with hyaluronic acid injections (known as viscosupplementation) makes almost no difference to pain or functioning and might raise risk of adverse events, suggests a review of 50 years of literature on the procedure.
Viscosupplementation has been used to treat knee osteoarthritis since the 1970s, but there are long-standing questions over its safety and efficacy.
Some 560 million people worldwide suffer from knee osteoarthritis, which involves inflammation and structural changes of the joints, resulting in joint pain and limitations to physical movement.
National and international guidelines vary in their recommendations, but most advise against the use of viscosupplementation. Researchers therefore set out to review 50 years’ worth of studies to evaluate the safety and efficacy of viscosupplementation. The studies compared viscosupplementation to placebo or no treatment.
Published in The BMJ, the main analysis of this review found that viscosupplementation was associated with a small reduction in pain compared with placebo, but the difference was tiny and was described as “clinically irrelevant.”
Their analysis showed that since 2009, there has been conclusive evidence that viscosupplementation and placebo treatment have led to the same clinical result in terms of pain reduction, meaning there is no point to having the injections.
They also found from 15 large trials on 6462 randomised participants that viscosupplementation was linked to a 49% higher risk of serious adverse events than placebo.
The authors say that based on their analysis of the studies between 2009 and 2021 alone, more than 12 000 patients were arguably unnecessarily subjected to these injections in viscosupplementation trials, which raises ethical concerns.
The study has some limitations in that it represents summary estimates and does not necessarily exclude the possibility that selected patient populations could benefit from viscosupplementation. Also, the researchers looked at adverse events that emerged rather than adverse events directly and clearly related to treatment.
However, strengths include the fact that this is the largest collection of randomised trials on viscosupplementation reported to date, which significantly decreases the risk of bias influencing the results.
As such, the authors conclude: “There is strong, conclusive evidence that among patients with knee osteoarthritis, viscosupplementation, compared with placebo, is associated with a clinically irrelevant reduction in pain intensity and with an increased risk of serious adverse events.
“The findings do not support broad use of viscosupplementation for the treatment of knee osteoarthritis.”
Source: The BMJ
