Saline Injections for Knee OA: Likely Therapeutic

New work presented at the recent meeting of the American Academy of Orthopaedic Surgeons indicates that intra-articular normal saline (IA-NS) injections may indeed have a therapeutic effect. The meta-analysis, entitled, “The Therapeutic Effect of Intra-articular Normal Saline Injections for Knee Osteoarthritis,” appeared in the December 27, 201+ edition of The American Journal of Sports Medicine.

The authors, Bryan M. Saltzman, M.D., Timothy Leroux, M.D., Maximilian A. Meyer, B.S., Bryce A. Basques, M.D., Jaskarndip Chahal, M.D., F.R.C.S.C., M.Sc., Bernard R. Bach, M.D., Adam B. Yanke, M.D., Brian J. Cole, M.D., M.B.A., were from Rush University Medical Center in Chicago and the University of Toronto in Canada.

Dr. Yanke commented to OTW, “Increasingly, new injection products are coming to market for the treatment of symptomatic osteoarthritis. The concern is that while many injections have been proven to be safe, we have a paucity of data on the efficacy of these treatments. Typically the highest level of study to evaluate this is a randomized prospective study with a known control or existing treatment. While in some ways, proving new treatments are better than existing treatments may be adequate, many trials have a placebo control to the study. This placebo treatment is typically saline only and theoretically should have no therapeutic effect. In reality, some treatments are demonstrating that they do not yield more improvement than placebo, but this is not for the reasons one may expect. When you drill down deeper, it turns out the saline groups show clinically meaningful improvement in their symptoms as well. As more trials are developed to try to bring new products to market it is important to make sure we are truly using the negative control that we believe we have.”

“Our study evaluated existing randomized trials via meta-analysis that used placebo as the control group to treat symptomatic osteoarthritis, resulting in the analysis of 14 different placebo cohorts. This analysis demonstrated that at six months following injection there was still clinically meaningful improvement based on subjective patient reported outcomes, confirming our clinical suspicion.”

“The findings of this study suggest that there may be a therapeutic effect of saline injections for osteoarthritis of the knee; however, there are limitations that need to be considered. All of these patients were enrolled in a randomized trial where they were initially blinded to the treatments and there may be a placebo effect secondary to being enrolled in a trial in itself. Therefore, our group is planning to evaluate the potential mechanism for saline to yield such a response, as well as developing a more appropriate placebo that does not result in any clinical improvement.”