Intra-articular Platelet-Rich Plasma vs Placebo Injection and Pain and Medial Tibial Cartilage Volume in Patients With Knee Osteoarthritis/Reply

• Published in: JAMA : the journal of the American Medical Association 2022-03, Vol.327 (12), p.1184
• Main Authors: Baria, Michael R, Flanigan, David C, Magalon, Jeremy, Frey, Alain, Kaux, Jean-Francois, Zhu, Zhaohua, Ding, Changhai, Lei, Yiting, Cui, Danli, Huang, Wei, Bennell, Kim L, Paterson, Kade L, Hunter, David J
• Format: Article
• Language: English
• Subjects: Biomedical materials; Cartilage; Cartilage diseases; Knee; Osteoarthritis; Pain; Platelets
• ISSN: 0098-7484; 1538-3598
• DOI: 10.1001/jama.2022.1306

Bennell et al reply to the comment by Drs Baria and Flanigan to their study. Drs Baria and Flanigan consider the platelet concentration used in their study too low to be PRP, claiming it was 1.2 times baseline. It appears they miscalculated this using the participant baseline whole blood platelet count and the manufacturer PRP mean platelet volume. They were unable to assess their participants' PRP platelet count, but data from the manufacturer and an independent study report a concentration of 1.6 times baseline, which exceeds the US Food and Drug Administration's minimum platelet concentration for PRP3 and meets Marx's definition. To their knowledge, no study has directly shown greater clinical efficacy with higher platelet concentrations; one found no relationship, while a systematic review found that high concentrations might be less effective. The study by Görmeli et al cited by Baria and Flanigan did not assess associations of platelet concentration and pain but found that 3 injections (the same number used in their study) were more effective than 1.