Is leukocyte-rich plasma less effective than leukocyte-poor plasma when injected into the knees of adults with osteoarthritis?

In this study limited by the absence of a placebo wing, leukocyte-rich and leukocyte-poor PRP injections were comparably effective in relieving pain in adults with mild to moderate knee osteoarthritis. Since it is unclear whether this treatment is any better than placebo, the American College of Rheumatology strongly recommends against using PRP injections.