Perspective from Gary L. Crump, MD, FACR
Perspective from Teri Puhalsky, BSN, RN, CRNI
Disclosures: This study was funded by the Australian National Health and Medical Research Council. Bennell reports personal fees from Wolters Kluwer to produce UpToDate knee OA clinical guidelines. Please see the study for all other authors’ relevant financial disclosures.
December 06, 2021
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Platelet-rich plasma injection fails to top placebo for pain, joint benefit in knee OA

Perspective from Gary L. Crump, MD, FACR
Perspective from Teri Puhalsky, BSN, RN, CRNI
Disclosures: This study was funded by the Australian National Health and Medical Research Council. Bennell reports personal fees from Wolters Kluwer to produce UpToDate knee OA clinical guidelines. Please see the study for all other authors’ relevant financial disclosures.
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Platelet-rich plasma injections failed to improve knee osteoarthritis symptoms or joint structure at 12 months, compared with a saline placebo, in patients with symptomatic, mild-to-moderate radiographic disease, according to data.

“The use of platelet-rich plasma (PRP) for the treatment of knee osteoarthritis is increasing, but most clinical guidelines do not currently recommend it due to the lack of high-quality evidence,” Kim L. Bennell, PhD, of the University of Melbourne, in Victoria, Australia, told Healio Rheumatology. “Also, there is much interest in being able to identify a treatment that not only improves symptoms but also slows structural disease progression. Our study was important to provide robust evidence about the effectiveness of a PRP product on both of these outcomes to inform clinical practice.”

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Platelet-rich plasma injections failed to improve knee OA symptoms or joint structure at 12 months, compared with a saline placebo, in patients with symptomatic, mild-to-moderate radiographic disease, according to data. Source: Adobe Stock.

To examine the effects of intra-articular PRP injection on symptoms and joint structure in patients with symptomatic, mild-to-moderate radiographic knee OA, Bennell and colleagues conducted a randomized, placebo-controlled blinded study. The researchers enrolled 288 participants in Sydney and Melbourne, aged 50 years or older with symptomatic knee OA, from Aug. 24, 2017, to July 5, 2019. Participants were randomly assigned 1:1 to receive three weekly intra-articular injections of either leukocyte-poor PRP or saline placebo.

The 12-month follow-up period ended July 22, 2020. The primary outcomes were 12-month change in overall average knee pain scores — based on a scale of 0-10, with higher scores indicating worse pain, and a minimum clinically important difference of 1.8 — and the percentage change in medial tibial cartilage volume, assessed via MRI. A total of 31 secondary outcomes examined pain, function, quality of life, global change and joint structures at 2 and/or 12 months. Both treatment groups had 140 individuals receive all three injections, with a total of 269 completing the trial.

According to the researchers, who published their findings in JAMA, PRP resulted in a mean change in knee pain scores of –2.1 points, compared with –1.8 for placebo, at 12 months, resulting in a difference of –0.4 points (95% CI, –0.9 to 0.2). The mean change in medial tibial cartilage volume, meanwhile, was –1.4% for PRP, compared with –1.2% for placebo, resulting in a –0.2% difference (95% CI, –1.9% to 1.5%). Among 31 secondary outcomes, 29 failed to demonstrate any significant between-group differences.

“The PRP tested did not show any greater benefits for improving pain or function than saline injections, nor did it change knee joint structure in people with mild-to-moderate knee osteoarthritis,” Bennell said. “Our results do not provide evidence to support the use of PRP for the treatment of knee osteoarthritis.”

“As PRP preparations are highly variable, we cannot necessarily generalize our results to all PRP preparations,” she added. “In line with person-centered care, the current evidence, risks and costs of various treatments for osteoarthritis, including PRP, should be outlined so that the patient can make an informed decision about their management.”