Effectiveness of Platelet-Rich Plasma in the Treatment of Knee Osteoarthritis: A Meta-analysis of Randomized Controlled Clinical Trials

Abstract

Background: The effectiveness of platelet-rich plasma (PRP) injections for knee osteoarthritis and the effects of leukocyte-poor PRP (LP-PRP) versus leukocyte-rich PRP (LR-PRP) are still controversial. Purpose: To assess the effectiveness of different PRP injections through a direct and indirect meta-analysis of randomized controlled trials. Study Design: Systematic review; Level of evidence, 1. Methods: A systematic literature search of electronic databases (PubMed, Cochrane Library, and EMBASE) was performed to locate randomized controlled trials published through March 2019 that compared PRP with control treatment. A random-effects meta-analysis was conducted to synthesize the evidence, and meta-regression analyses were conducted to determine the influence of trial characteristics. An indirect comparison was performed to assess the effects of LP-PRP and LR-PRP compared with hyaluronic acid (HA). Results: A total of 21 trials were included. A clinically important benefit for pain relief was seen for intra-articular PRP compared with intra-articular saline (standardized mean difference [SMD] = –1.38 [95% CI, –2.07 to –0.70]; P < .0001; I 2 = 37%) and corticosteroid solution injection (SMD = –2.47 [95% CI, –3.34 to –1.61]; P < .00001; I 2 = 47%). As a result of heterogeneity ( I 2 = 89%), there was no conclusive effect compared with HA, even though the pooling effect provided clinically relevant pain relief (SMD = –0.59 [95% CI, –0.97 to –0.21]; P = .003). Indirect meta-analysis showed that there was no significant difference between LR-PRP and LP-PRP. Conclusion: PRP injections are beneficial for pain relief and functional improvement in knee osteoarthritis. Larger, randomized high-quality studies are needed to compare the effects of LP-PRP and LR-PRP.

Predictors of Effectiveness of Platelet-Rich Plasma Therapy for Knee Osteoarthritis: A Retrospective Cohort Study

“…This seems natural because if the KOA worsens, the efficacy of PRP therapy may decrease. Interestingly, most previous studies concluded that the severity of KOA was not associated with the efficacy of PRP therapy [ 4 , 5 , 13 ]. This could be attributed to the fact that most previous prospective studies excluded patients with severe KOA (KL grade 4).…”

“…PRP therapy is the most frequently used cell-based therapy for KOA because it is simple, minimally invasive, inexpensive, and has fewer complications than arthroplasty [ 3 ]. A meta-analysis of clinical trials involving intra-articular (IA) PRP injection in patients with KOA demonstrated that PRP has favorable effects on improving pain and functional scores compared with HA, steroid, and saline injections [ 4 , 5 ]. A meta-analysis of 21 randomized controlled clinical trials (RCTs) demonstrated that a clinically important benefit for pain relief was seen for intra-articular PRP compared with intra-articular saline (standardized mean difference (SMD) = −1.38 (95% CI, −2.07 to −0.70); p < 0.0001; I 2 = 37%) and corticosteroid solution injections (SMD = −2.47 (95% CI, −3.34 to −1.61); p < 0.00001; I 2 = 47%) [ 4 ].…”

“…A meta-analysis of clinical trials involving intra-articular (IA) PRP injection in patients with KOA demonstrated that PRP has favorable effects on improving pain and functional scores compared with HA, steroid, and saline injections [ 4 , 5 ]. A meta-analysis of 21 randomized controlled clinical trials (RCTs) demonstrated that a clinically important benefit for pain relief was seen for intra-articular PRP compared with intra-articular saline (standardized mean difference (SMD) = −1.38 (95% CI, −2.07 to −0.70); p < 0.0001; I 2 = 37%) and corticosteroid solution injections (SMD = −2.47 (95% CI, −3.34 to −1.61); p < 0.00001; I 2 = 47%) [ 4 ]. In a previous RCT investigating the efficacy of PRP, the responder rate of Outcome Measures in Rheumatology (OMERACT)-Osteoarthritis Research Society International (OARSI) responder criteria was 65.5% at 12 months [ 6 ].…”

“…Conversely, the OARSI guidelines on developing patient-focused treatment recommendations do not recommend PRP therapy because the evidence in support of this treatment is of low quality [ 7 ]. Most studies to date treated only patients with mild to moderate KOA and compared the effectiveness of PRP therapy with other treatments such as HA injection [ 4 , 8 ]. In the clinical setting, however, many patients with severe KOA wish to undergo PRP therapy as well.…”

Case Report: Rehabilitation After Platelet-Rich Growth Factors’ Intra-Articular Injections for Knee Osteoarthritis: Two Case Reports of a Home-Based Protocol

“…Injections of blood-derived products are a widely diffused treatment for KOA, and increasing evidence shows their safety and efficacy ( Shen et al, 2017 ; Hohmann et al, 2020 ; Nie et al, 2021 ). However, while they can often improve symptoms, in many cases, pain, functional impairment, and reduced quality of life persist even after the injections.…”