Intra-Articular More Efficacious Than Oral Therapy for Knee Osteoarthritis Pain

SAN DIEGO, CA—Regarding knee osteoarthritis pain, intra-articular (IA) treatments were more efficacious than oral treatments possibly because of the integrated IA placebo effect, reported study authors at the 2013 ACR/ARHP Annual Meeting.

There is a variety of symptomatic interventions available for knee osteoarthritis, but “head-to-head comparisons are limited, and no study compares all of the treatment options against each other,” stated Raveendhara R. Bannuru, MD, from Tufts Medical Center, Tufts University, Boston, MA. 

Dr. Bannuru and his team performed a network meta-analysis, an innovative approach for comparing multiple interventions in a single analysis – to combine direct (head-to-head) and indirect (through a common comparator) in efforts to increase power and precision for the effect estimates and to assign probabilities of superiority.

Study authors searched Medline, EMBASE, Google Scholar, ISI Web of Science and Cochrane Database from inception to August 26, 2013 with no language restrictions and actively sought unpublished data. Randomized controlled trials conducted in adults with knee OA comparing ≥2 of the following most widely prescribed treatments were included: acetaminophen, non-selective NSAIDs (eg, diclofenac, ibuprofen, naproxen), COX-2 selective NSAIDs (eg, celecoxib), IA corticosteroids, IA hyaluronic acid, oral placebo, and IA placebo. Efficacy for pain and function at 12 weeks from baseline was calculated for each study.

A total of 132 trials were eligible, of which 124 reported pain and 72 reported function outcomes. These trials included 32,481 patients aged 45–75 years old.

Relative effect sizes for pain were statistically significant for all treatments compared with oral placebo. “For function, all interventions except IA corticosteroids were significantly superior to oral placebo. For stiffness, oral treatments were significantly better than oral placebo and acetaminophen. Hyaluronic acid was significantly better than IA placebo,” according to Dr. Bannuru.

“Intra-articular treatments were superior to oral NSAIDs possibly due to the integrated IA placebo effect,” Dr. Bannuru concluded.