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Meta-Analysis
. 2021 Dec;13(1_suppl):364S-375S.
doi: 10.1177/1947603520931170. Epub 2020 Jun 19.

PRP Injections for the Treatment of Knee Osteoarthritis: A Meta-Analysis of Randomized Controlled Trials

Giuseppe Filardo  1   2 , Davide Previtali  2 , Francesca Napoli  2 , Christian Candrian  2 , Stefano Zaffagnini  1 , Alberto Grassi  1
Affiliations
Meta-Analysis

PRP Injections for the Treatment of Knee Osteoarthritis: A Meta-Analysis of Randomized Controlled Trials

Giuseppe Filardo et al. Cartilage. 2021 Dec.

Abstract

Objective: To evaluate effectiveness, in terms of patient-reported outcome measures, of platelet-rich plasma (PRP) injections for knee osteoarthritis compared to placebo and other intraarticular treatments.

Design: PubMed, Cochrane Library, Scopus, Embase, Web of Science, as well as the gray literature were searched on January 17, 2020. Randomized controlled trials (RCTs) comparing PRP injections with placebo or other injectable treatments, in any language, on humans, were included. Risk of bias was assessed following the Cochrane guidelines; quality of evidence was graded using the GRADE guidelines.

Results: Thirty-four RCTs, including 1403 knees in PRP groups and 1426 in control groups, were selected. WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) score favored PRP, with a statistically and clinically significant difference versus placebo at 12-month follow-up (P = 0.02) and versus HA (hyaluronic acid) at 6-month (P < 0.001) and 12-month (P < 0.001) follow-ups. A clinically significant difference favoring PRP versus steroids was documented for VAS (Visual Analogue Scale) pain (P < 0.001), KOOS (Knee Injury and Osteoarthritis Outcome Score) pain (P < 0.001), function in daily activities (P = 0.001), and quality of life (P < 0.001) at 6-month follow-up. However, superiority of PRP did not reach the minimal clinically important difference for all outcomes, and quality of evidence was low.

Conclusions: The effect of platelet concentrates goes beyond its mere placebo effect, and PRP injections provide better results than other injectable options. This benefit increases over time, being not significant at earlier follow-ups but becoming clinically significant after 6 to 12 months. However, although substantial, the improvement remains partial and supported by low level of evidence. This finding urges further research to confirm benefits and identify the best formulation and indications for PRP injections in knee OA.

Keywords: PRP; hyaluronic acid; knee osteoarthritis; meta-analysis; placebo; platelet-rich plasma; steroids.

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Conflict of interest statement

Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article. All authors declare no support from any organization for the submitted work. CC has received institutional support outside the present work from Medacta International SA, Johnson & Johnson, Lima Corporate, Zimmer Biomet, and Oped AG. SZ received personal fees from I+ SRL, research grants outside the submitted work from Fidia Farmaceutici SPA, CartiHeal Ltd, IGEA Clinical Biophysics, BIOMET, and Kensey Nash, and has a Springer patent with royalties paid.

Figures

Figure 1.
Figure 1.
PRISMA flowchart of the study selection process.
Figure 2.
Figure 2.
Results of the meta-analysis for the different study outcomes.
See this image and copyright information in PMC

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References

    1. Filardo G, Kon E, Roffi A, Di Matteo B, Merli ML, Marcacci M. Platelet-rich plasma: why intra-articular? A systematic review of preclinical studies and clinical evidence on PRP for joint degeneration. Knee Surg Sports Traumatol Arthrosc. 2015;23(9):2459-74. - PMC - PubMed
    1. Gilbertie JM, Long JM, Schubert AG, Berglund AK, Schaer TP, Schnabel LV. Pooled platelet-rich plasma lysate therapy increases synoviocyte proliferation and hyaluronic acid production while protecting chondrocytes from synoviocyte-derived inflammatory mediators. Front Vet Sci. 2018;5:150. - PMC - PubMed
    1. Sundman EA, Cole BJ, Karas V, Della Valle C, Tetreault MW, Mohammed HO, et al.. The anti-inflammatory and matrix restorative mechanisms of platelet-rich plasma in osteoarthritis. Am J Sports Med. 2014;42(1_suppl):35-41. - PubMed
    1. Chen WH, Lin CM, Huang CF, Hsu WC, Lee CH, Ou KL, et al.. Functional recovery in osteoarthritic chondrocytes through hyaluronic acid and platelet-rich plasma-inhibited infrapatellar fat pad adipocytes. Am J Sports Med. 2016;44(10):2696-705. - PubMed
    1. Gato-Calvo L, Hermida-Gomez T, Romero CR, Burguera EF, Blanco FJ. Anti-inflammatory effects of novel standardized platelet rich plasma releasates on knee osteoarthritic chondrocytes and cartilage in vitro. Curr Pharm Biotechnol. 2019;20:920-33. - PubMed

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