Are leukocyte-poor or multiple injections of platelet-rich plasma more effective than hyaluronic acid for knee osteoarthritis? A systematic review and meta-analysis of randomized controlled trials

Mechanisms and applications of the regenerative capacity of platelets-based therapy in knee osteoarthritis

Osteoarthritis (OA) is the most prevalent joint disease in the elderly population and its substantial morbidity and disability impose a heavy economic burden on patients and society. Knee osteoarthritis (KOA) is the most common subtype of OA, which is characterized by damage to progressive articular cartilage, synovitis, and subchondral bone sclerosis. Most current treatments for OA are palliative, primarily aim at symptom management, and do not prevent the progression of the disease or restore degraded cartilage. The activation of α-granules in platelets releases various growth factors that are involved in multiple stages of tissue repair, suggesting potential for disease modification. In recent years, platelet-based therapies, such as platelet-rich plasma, platelet-rich fibrin, and platelet lysates, have emerged as promising regenerative treatments for KOA, but their related effects and mechanisms are still unclear. Therefore, this review aims to summarize the biological characteristics and functions of platelets, classify the products of platelet-based therapy and related preparation methods. Moreover, we summarize the basic research of platelet-based regeneration strategies for KOA and discuss the cellular effects and molecular mechanisms. Further, we describe the general clinical application of platelet-based therapy in the treatment of KOA and the results of the meta-analysis of randomized controlled trials.

Efficacy of platelet-rich plasma in the treatment of thin endometrium: a meta-analysis of randomized controlled trials

BACKGROUND

Thin endometrium (TE) is a common cause of female infertility in clinical practice. Platelet-rich Plasma (PRP) therapy becomes a novel treatment for thin endometrium; however, its clinical application remains controversial. This meta-analysis aims to evaluate the therapeutic effects of intrauterine autologous PRP infusion in women with thin endometrium through relevant randomized controlled trials (RCTs).

METHODS

We systematically searched studies published in English from inception until June 2024 in databases such as PubMed, The Cochrane Library, Embase, Web of Science, and MEDLINE. Search terms included "Platelet-Rich Plasma," "thin endometrium," "endometrial thickness," "infertility," "pregnancy," "reproduction," and "adverse reactions". RCTs identified through the search were subjected to systematic review and meta-analysis, and data were analyzed using fixed-effects or random-effects models based on heterogeneity.

RESULTS

Eight RCTs involving 678 patients with thin endometrium were included. Patients receiving PRP infusion demonstrated significantly superior outcomes compared to the control group in endometrial thickness (MD: 1.23, 95%CI: 0.87 to 1.59, P = 0.000), clinical pregnancy rate (RR: 2.04, 95%CI: 1.52 to 2.76, P = 0.000), live birth rate (RR: 2.46; 95%CI: 1.57 to 3.85, P = 0.000), cycle cancellation rate (RR: 0.46, 95%CI: 0.23 to 0.93, P = 0.000), and embryo implantation rate (RR: 2.71; 95%CI: 1.91 to 3.84, P = 0.000). There were no statistically significance in spontaneous abortion rate (RR: 0.85, 95%CI: 0.40 to 1.78, P = 0.659), chemical pregnancy rate (RR: 1.84, 95%CI: 0.72 to 4.72, P = 0.204) and endometrial vascular improvement rate (RR: 1.10; 95%CI: 0.89 to 1.38, P = 0.367) between the two groups. The limitations of this study includes that, we only included single lauguage for literature research, the sample size and heterogeneity which could cause criteria bias.

CONCLUSION

Intrauterine PRP infusion may be an effective and safe treatment for women with thin endometrium. Further high-quality, large-sample, randomized controlled trials are needed to validate the reliability of our results.

TRIAL REGISTRATION

The review protocol is registered on PROSPERO with registration number CRD42023490421, and no modifications were made to the information provided at registration.

Efficacy and safety of platelet-rich plasma and hyaluronic acid combination therapy for knee osteoarthritis: a systematic review and meta-analysis

BACKGROUND

This study aimed to evaluate whether a combination of platelet-rich plasma (PRP) and hyaluronic acid (HA) is more effective and safer than injection alone for treating KOA.

MATERIALS AND METHODS

MEDLINE (PubMed), the Cochrane Library, EMBASE, and Web of Science databases were systematically searched for articles published until January 2024, and gray literature and bibliographic references were searched. All published randomized controlled trials (RCTs) compared pain, functional outcomes, and adverse events (AEs) associated with PRP + HA therapy vs. PRP or HA treatments. Two independent researchers extracted the pertinent data and evaluated the methodological quality following the PRISMA guidelines. The primary outcomes were pain, functional outcomes, and AEs. A fixed-effects model was used for data analysis in cases with low heterogeneity (P > 0.10 and I2 < 50%). Otherwise, a random effects model was used.

RESULTS

Ten RCTs involving 943 patients were included in the analysis. The statistical findings did not differ between the treatment of PRP + HA and PRP alone, while a discernible enhancement in treatment efficacy was observed when compared to HA monotherapy: the visual analog scale scores at 1- (mean difference[MD], -1.00; 95% CI: -1.37 - -0.62; P < .001), 6- (MD, -1.87; 95% CI: -3.46 - -0.28; P = .02), 12-months (MD, -2.07; 95% CI: -3.77 - -0.38; P = .02), and the Western Ontario and McMaster Universities Arthritis Index total scores at 12-months (MD, -8.82; 95% CI: -14.48 - -3.16; P = .002). The incidence of adverse events was notably lower with PRP + HA than with HA alone (OR, 0.37; 95% CI: 0.19 - 0.69; P = .00) or PRP alone (OR, 0.51; 95% CI, 0.30 - 0.87; P = .01).

CONCLUSIONS

PRP + HA therapy resulted in more pronounced pain and functional improvement in symptomatic KOA patients than HA treatments, and combination therapy may have higher clinical safety than PRP or HA monotherapy.

Adverse events related to platelet-rich plasma therapy and future issues to be resolved

Platelet-rich plasma (PRP) is the portion of plasma with a platelet concentration above baseline that is recovered through centrifugation of autologous blood. PRP therapy is currently used for wound healing and pain relief in diverse medical fields. Although there have been recent reports of adverse events (AEs) possibly related to PRP treatment, the safety profile of PRP treatment remains unclear. Therefore, this review discusses the risks inherent in PRP therapy and the current issues by surveying reports on AEs associated with PRP treatment within different fields. PubMed was searched for research articles referring to AEs associated with PRP therapy from inception to January 2024. Literature survey revealed that PRP therapy may involve several AEs, including postoperative infections, blindness, inflammation, allergic reactions, and nodule development. The most commonly reported AE was postoperative infections. Since PRP therapy generally proceeds in the process of blood collection, manufacturing, and administration to patients, it is conjectured that PRP may have been contaminated with microorganisms at some point in this series of processes, leading to bacterial infection. Additionally, because PRP cannot be sterilized like pharmaceuticals, it is important to prevent microbial contamination during each PRP treatment process. However, the specific process that involves the risk of microbial contamination remains unclear. To take measures to prevent microbial contamination of PRP, it may be necessary to elucidate the risk factors for microbial contamination during PRP treatment. It may be important to elucidate the effectiveness and risks of PRP therapy as well as to establish a follow-up system after PRP treatment. Currently, most reports of AEs related to PRP therapy are case reports; therefore, the accumulation of high-quality evidence and detailed verification are necessary to determine the causal relationship between PRP therapy and each AE.

A Comprehensive Summary of the Meta-Analyses and Systematic Reviews on Platelet-Rich Plasma Therapies for Knee Osteoarthritis

INTRODUCTION

Osteoarthritis (OA), including that of the knee joint, represents a significant proportion of musculoskeletal injuries in the Canadian Armed Forces (CAF) due to the frequent, high-stress physical activity for which member participation is necessary. Platelet-rich plasma (PRP) is a conservative, autologous treatment that has the potential to relieve symptoms and improve functionality of military members to decrease the impact of the disease and ultimately strengthen the CAF.

MATERIALS AND METHODS

A search of systematic reviews and meta-analyses was conducted to determine the efficacy of PRP injections in treating knee OA. The Scopus database, PubMed database, and Omni academic search tools were scoped for relevant publications. English literature, published up to and including March 2023, that investigated only clinically randomized controlled trials (RCTs) was eligible for inclusion. The results of network meta-analyses were investigated and summarized independent of reviews and non-network meta-analyses.

RESULTS

A total of 225 unique systematic reviews and meta-analyses were initially identified, of which 39 publications, including 7 network meta-analyses, adhered to the defined inclusion and exclusion criteria. PRP was found to significantly alleviate symptoms of pain based on the visual analog scale and Western Ontario and McMaster Universities Arthritis Index pain scores within the 12-month follow-up. Function, activity, sport, quality of life, and stiffness were additionally determined to generally improve to a greater extent from PRP treatment compared to controls, while adverse effects were minor and temporary. PRP placed in the top 3 in 9 reported surface under the cumulative ranking curves, while individually reported rankings of leukocyte-poor and leukocyte-rich PRP both placed in the top 4. The clinical recommendations made were generally positive, with 17 publications acknowledging the benefits of PRP, 3 supporting possible efficacy, and an additional 8 recommending that it be an option for the conservative treatment of knee OA.

CONCLUSION

The results of this review support the efficacy of PRP for relieving symptoms of pain and improving function, stiffness, and quality of life for patients experiencing knee OA within 12 months. As a result, leukocyte-poor-PRP could be considered for members of the CAF with mild to moderate knee OA (Kellgren-Lawrence grades 1-3) to slow the progression of OA and extend the military careers of CAF members. There continues to be a need for future studies to investigate the longer-term effects of PRP to verify sustained benefits at follow-up points greater than 12 months, including findings of improvement in a delayed fashion at the 3- and 6-month timeframe compared to hyaluronic acid treatment.

Infiltration therapy in the context of cartilage surgery

Guideline-based surgical cartilage therapy for focal cartilage damage offers highly effective possibilities to sustainably reduce patients' complaints and to prevent or at least delay the development of early osteoarthritis. In the knee joint, it has the potential to reduce almost a quarter of the arthroses requiring joint replacement caused by cartilage damage. Biologically effective injection therapies could further improve these results. Based on the currently available literature and preclinical studies, intra- and postoperative injectables may have a positive effect of platelet-rich plasma/fibrin (PRP/PRF) and hyaluronic acid (HA) on cartilage regeneration and, in the case of HA injections, also on the clinical outcome can be assumed. The role of a combination therapy with use of intra-articular corticosteroids is lacking in the absence of adequate study data and cannot be defined yet. With regard to adipose tissue-based cell therapy, the current scientific data do not yet justify any recommendation for its use. Further studies also regarding application intervals, timing and differences in different joints are required.