Do hyaluronic acid injections in patients with knee degenerative joint disease (DJD) improve pain and function?
The highest quality studies, which are now fairly plentiful, show that hyaluronic acid injections are only minimally better than sham injections in improving pain and function in patients with knee DJD. (Level of Evidence = 1a−)
These authors searched multiple databases and a clinical trial registry to identify randomized trials comparing hyaluronic acid injections with control treatments in patients with knee DJD. Studies had to include at least 30 patients in each group, include pain and function scales for which minimal clinically important differences are established, and have at least four weeks of follow-up. The authors do not describe the process of article inclusion. Ultimately, they included 19 studies with nearly 4,500 patients: 14 used sham injections as the comparator; two used usual care; and three used injections combined with some other active treatment. The authors did not find any statistically significant potential for publication bias. In the studies using sham injections, hyaluronic acid was slightly better at improving pain and function, but the improvement was not clinically important. Similarly, the improvements in double-blind trials were also not clinically significant. Among the other studies with designs at higher risk of bias, the magnitude of improvement in pain and function were really impressive. We have seen this story before: The stuff looks really effective until the studies are done correctly.
Study design: Meta-analysis (randomized controlled trials)
Funding source: Self-funded or unfunded
Setting: Outpatient (specialty)
Reference: JevsevarDDonnellyPBrownGACumminsDSViscosupplementation for osteoarthritis of the knee: a systematic review of the evidence. J Bone Joint Surg Am2015; 97( 24): 2047– 2060.