platelet rich plasma for knee osteoarthritis

Platelet Rich Plasma for Knee Osteoarthritis: Recent Study and Comment

A study by Bennell , Patterson and Metcalf et. al. entitled “Effect of Intraarticular Platelet-Rich Plasma Versus Placebo Injection On Pain And Medial Tibial Cartilage Volume In Patients With Knee Osteoarthritis” was recently published in the Journal of American Medical Association1. The study concluded that use of platelet-rich plasma (PRP) did not significantly improve symptoms or joint structure at 12 months in patients with mild to moderate osteoarthritis (OA).

Publication of the study elicited a significant response as published in the letters to the editor of the March 22 /29 220 edition of the Journal2,3. Letter writers questioned the platelet concentration in the platelet rich plasma and another confounding variables in the study which they felt were not addressed . They also referenced a recent meta-analysis of more than 20 randomized clinical trials which demonstrated benefits of PRP for osteoarthritis as compared with other injectable treatments4.

Importantly, Bennell and his group chose a coprimary structural outcome of cartilage volume because hypothetically  they felt that their limited data might allow for definitive conclusions. They also used secondary subjective outcome measures. They  concluded that their study as well as other studies referenced have failed to show any statistically significant improvement in cartilage structure following use of PRP.

It is my opinion that at this time the use of PRP for knee osteoarthritis remains investigational. There may be studies  demonstrating symptomatic relief but most times this relief is short term and certainly has not been shown to affect the natural history of osteoarthritis. To the best of my knowledge there are no studies which demonstrate significant structural improvement following use of PRP or any other injectables. Perhaps with modifications and improvements in PRP systems and protocols , clinical and structural benefits may be found but for the time being further investigation is required before use of PRP for OA becomes standard of care.


1Bennell  KL, Paterson  KL, Metcalf  BR,  et al.  Effect of intra-articular platelet-rich plasma vs placebo injection on pain and medial tibial cartilage volume in patients with knee osteoarthritis: the RESTORE randomized clinical trial.  JAMA. 2021;326(20):2021-2030. doi:1001/jama.2021.19415

2Magalon J, Frey A, Kaux J. Intra-articular Platelet-Rich Plasma vs Placebo Injection and Pain and Medial Tibial Cartilage Volume in Patients With Knee Osteoarthritis. 2022;327(12):1185–1186. doi:10.1001/jama.2022.1303

3Baria MR, Flanigan DC. Intra-articular Platelet-Rich Plasma vs Placebo Injection and Pain and Medial Tibial Cartilage Volume in Patients With Knee Osteoarthritis. 2022;327(12):1184–1185. doi:10.1001/jama.2022.1306

4Nie  LY, Zhao  K, Ruan  J, Xue  J.  Effectiveness of platelet-rich plasma in the treatment of knee osteoarthritis: a meta-analysis of randomized controlled clinical trials.  Orthop J Sports Med. 2021;9(3):2325967120973284. doi:1177/2325967120973284

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