Intra-articular treatments appear superior to NSAIDs for knee osteoarthritis in meta-analysis

A meta-analysis comparing treatments for knee osteoarthritis found that intra-articular treatments were superior to NSAIDs.

Researchers performed a systematic review and network meta-analysis of trials published through Aug. 15, 2014, and unpublished data to look at the efficacy of treatments for primary knee osteoarthritis. Randomized trials of adults with knee osteoarthritis that compared 2 or more of the following treatments were included: acetaminophen, diclofenac, ibuprofen, naproxen, celecoxib, intra-articular corticosteroids, intra-articular hyaluronic acid, oral placebo, and intra-articular placebo. The researchers calculated standardized mean differences for pain, function, and stiffness at 3-month follow-up. The study results appeared in the Jan. 6 Annals of Internal Medicine.

One hundred thirty-seven studies published between 1980 and 2014 were included, involving a total of 33,243 patients. Analyses of pain-related outcomes included 129 trials and 32,129 patients. All of the interventions did significantly better than oral placebo in improving pain, with hyaluronic acid being most effective (effect size, 0.63; 95% credible interval, 0.39 to 0.88) and acetaminophen being least effective (effect size, 0.18; 95% credible interval, 0.04 to 0.33). For improving function (76 trials, 24,059 patients), all of the interventions except intra-articular corticosteroids were significantly better than oral placebo. For improving stiffness (55 trials, 18,267 patients), no significant differences were seen between most of the interventions.

The authors noted that their study lacked long-term data, that reporting of safety data was inadequate, that there were few head-to-head comparisons, and that publication bias was possible. However, they concluded that intra-articular treatments performed better than NSAIDs for knee osteoarthritis and that all of the treatments with the exception of acetaminophen yielded clinically significant improvement in pain versus baseline. They hypothesized that the effect of intra-articular treatment could have been due to the integrated intra-articular placebo effect. “This information, along with the safety profiles and relative costs of included treatments, should be helpful to clinicians when making care decisions tailored to individual patient needs,” the authors wrote.

The authors of an accompanying editorial said that the study provided a sophisticated analysis of available evidence and stressed that such innovative research models will be needed in the future to increase understanding of how best to optimize pain control and to help develop an approach to effective treatment. In addition, they said, the pathophysiology of osteoarthritis pain, including peripheral nociceptive and inflammatory triggers and central sensitization, should be taken into account. “A clear understanding of the role of placebo, pain pathophysiology, and patient preferences should be key factors facilitating shared decision making in treating patients with knee [osteoarthritis],” the editorialists concluded.