Monday, April 25, 2016

Hyaluronic acid injections don't help knee DJD

- Jennifer Middleton, MD, MPH

Options for helping patients with knee degenerative joint disease (DJD) seem to be getting more limited. A POEM in the April 15 AFP reviews a meta-analysis showing that hyaluronic acid injection is no better than sham injection for treating pain from knee DJD. This meta-analysis confirms what other recent studies have found; hyaluronic acid injections don't meaningfully help patients with knee DJD.

The meta-analysis included 19 randomized controlled trials comparing hyaluronic acid injections to sham injections (14 trials), usual care (2 trials), or combined with some other treatment (3 trials). The non-blinded trials did show modest improvement in pain scores, but the double-blinded trials showed negligible improvements, if any. Although early studies of hyaluronic acid suggested it was effective, these studies tended to be small and were frequently unblinded or inadequately blinded. Higher quality double-blinded studies, especially when considered in aggregate in this meta-analysis, did not confirm this benefit.

The placebo effect can be powerful, as evidenced by participants' perceived improvements in the non-blinded trials compared to the double-blind trials. And, perhaps, that is not always a negative; I suspect those participants who did feel better in the non-blinded trials were pleased with the improvements they noted in their pain. Unfortunately, the placebo effect with hyaluronic acid comes with cost and risk; injections can cost hundreds of dollars for one dose, and typical therapeutic regimens involve a series of 3-5 injections over several weeks. Injecting into a joint is also not a zero-risk procedure; although rare, serious complications like joint infection can occur.

Hyaluronic acid injections' limitations should not come as a surprise; a web search of "hyaluronic acid knee injections" reveals many critical lay press articles over the last couple of years, and the American Association of Orthopedic Surgeons (AAOS) even states "We cannot recommend using hyaluronic acid for symptomatic arthritis of the knee" in their Summary of Recommendations for Treatment of Osteoarthritis of the Knee (which was cited in this 2014 AFP article). I suspect, though, that I am not alone in seeing this intervention still commonly offered for patients, both by family physician colleagues and local orthopedists. 

With glucosamine and chondroitin also now out of favor for treating knee DJD, non-surgical options for helping patients are currently limited to oral analgesics and, possibly, intra-articular corticosteroid injections - though the AAOS cites a lack of data regarding corticosteroid injections' efficacy in their summary statement as well. Given the prevalence of knee DJD, we can only hope that researchers are investigating novel treatment methods to help those patients who are not yet (or will never be) candidates for knee joint replacement.

You can read more at the AFP By Topic on Arthritis and Joint Pain, and you might also want to check out the Choosing Wisely recommendations from the AAOS (though Dr. Lin critiqued the limitations of these recommendations in this post from last year). The AFP Choosing Wisely search tool is a handy way to review other interventions shown to be of little utility for orthopedic conditions as well as other specialties; you can access it from the AFP home page or bookmark it on your personalized AFP Favorites page.

How are you treating knee DJD in your office?