Viscosupplementation for knee osteoarthritis has little benefit, analysis finds

Viscosupplementation for knee osteoarthritis offers little clinical benefit and increases risk for adverse events, a new study has found.

Researchers performed a systematic review and meta-analysis to determine the risks and benefits of viscosupplementation, a treatment involving intra-articular injection of hyaluronic acid, for knee osteoarthritis. Randomized or quasi-randomized, controlled trials comparing viscosupplementation with a sham or nonintervention control in adults with symptomatic knee osteoarthritis were included. The primary outcomes of the review and meta-analysis were pain intensity and flareups; the secondary outcomes were function and severe adverse events. The study results were published online June 12 by Annals of Internal Medicine.

Overall, 89 trials involving 12,667 adults were included. The average patient age ranged from 50 to 72 years. Sixty-eight trials had a sham control, 22 trials used cross-linked forms of hyaluronic acid, and 40 trials had more than three months' follow-up. Seventy-one trials involving 9,617 patients found that viscosupplementation resulted in a moderate decrease in pain (effect size, −0.37 [95% CI, −0.46 to −0.28]). In five unpublished trials involving 1,149 patients, the effect size was −0.03 (95% CI, −0.14 to 0.09), while 18 large trials with blinded outcome assessment involving 5,094 patients showed an effect size of −0.11 (95% CI, −0.18 to −0.04), which was clinically irrelevant. Six trials involving 811 patients showed a nonstatistically significant increase in risk for flareups with viscosupplementation (relative risk, 1.51 [95% CI, 0.84 to 2.72]), while 14 trials in 3,667 patients showed that viscosupplementation increased risk for serious adverse events (relative risk, 1.41 [95% CI, 1.02 to 1.97]). The authors noted important between-trial heterogeneity and an asymmetrical funnel plot, writing that “Trial size, blinded outcome assessment, and publication status were associated with effect size.”

The authors acknowledged that most of the included trials were of low quality and many did not report safety data. However, they concluded that viscosupplementation offers “minimal or nonexistent” benefit for pain and function in patients with knee osteoarthritis. “Because of increased risks for serious adverse events and local adverse events, the administration of these preparations should be discouraged,” they wrote.