By: 18 October 2013

Contrary to recent reviews hyaluronic acid injections may help reduce pain and enhance function in knee osteoarthritis

KneePainA new meta-analysis of 29 randomised studies involving more than 4,500 patients with knee osteoarthritis (OA) found that intra-articular hyaluronic acid (HA) injections provided significant improvement in pain and function compared to saline injections.
The study, published online in Clinical Medicine Insights: Arthritis and Musculoskeletal Disorders, included results from randomised peer-reviewed studies of six HA injection brands, with identical treatment follow-up between the treatment and control groups. The results are in contrast to the Rutjes et al (2012) paper that included data from many HA products which are not FDA approved and not available in the US.

“The findings of the meta-analysis are important but not unexpected,” said Mark Snyder, MD, an orthopaedic surgeon from the TriHealth Orthopedic and Spine Institute in Cincinnati, Ohio, USA. “The safety data in the meta-analysis comes from studies that only used FDA-approved HAs. The data set is consistent with what I and many other physicians have clinically observed for many years – HAs have been found to be safe, can help relieve knee pain from osteoarthritis, and are appropriate treatment for people with mild to moderate forms of the disease.”

While neither HA nor saline injections resulted in serious adverse events, researchers found very large treatment effects between four and 26 weeks for knee pain and function compared to pre-injection values, with standardised mean difference (SMD) values ranging from 1.07 to 1.37 (p < 0.001). These changes represent approximately 50 percent improvement in pain and function from baseline with viscosupplementation. Additionally, improvements in knee pain and function with viscosupplementation were statistically superior compared to saline injections (p < 0.001) for both. These findings differ with the analysis conducted this year by an US-based orthopaedic physician society which also included products that were not FDA approved.

“Studies such as this are critical in helping physicians and patients make informed decisions,” said Dr Snyder. “Currently, there are limited treatment options available to healthy people with mild to moderate OA. Access to HA treatments is a great option for those who are seeking help in staying active.”

The authors of the review acknowledge that the study’s findings have limitations. Their analysis did not include many subjects with end-stage knee OA or specify efficacy among the different types of HAs. The authors also noted that efficacy outcomes were inconsistent across studies and that there was evidence of publication bias in OA knee pain outcomes. There were no statistically significant differences between HA and saline controls for any safety outcome.

Junior editor at Fintech Intel