Effect of two different preparations of platelet-rich plasma on synoviocytes

Systematic Review of Randomized Controlled Trials Evaluating the Use of Platelet-Rich Plasma for Knee Osteoarthritis: Adherence to Minimum Information for Studies Evaluating Biologics in Orthopaedics

BACKGROUND

The Minimum Information for Studies Evaluating Biologics in Orthopedics (MIBO) guidelines were developed in May 2017 to encourage improved reporting standards, promote increased transparency and reproducibility, and enhance clinical evaluation capabilities. The MIBO guidelines consist of 23 checklist items considered necessary to critically appraise clinical studies evaluating platelet-rich plasma (PRP).

PURPOSE

To assess randomized controlled trials that evaluated PRP for the treatment of knee osteoarthritis in order to systematically review their adherence to the MIBO guidelines.

STUDY DESIGN

Systematic review. Level 1a.

METHODS

A search was performed following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The inclusion criteria were randomized controlled trials reporting on knee osteoarthritis treated with intra-articular PRP. The studies were categorized into pre-, peri-, and post-MIBO groups based on the start date of data collection. The overall MIBO scores, defined as percentage of checklist items out of the 23 checklist items reported in 1 study, individual item scores, defined as percentage of studies reporting the checklist item within a specified group, and overall item score defined as the average of the individual item scores from all the included studies were calculated.

RESULTS

The review included 87 studies (7925 patients; 8118 knees). Of these, 51 studies were assigned to the pre-MIBO group, 19 studies to the peri-MIBO group, and 17 studies to the post-MIBO group. The overall MIBO score was 72%. No statistically significant differences in MIBO scores were found among the 3 MIBO groups (P = .345). The majority of the studies (62 studies; 71%) had MIBO scores <80%. MIBO items with particularly low item scores included reporting of whole-blood characteristics (20%), platelet recovery rate (22%), PRP analysis (30%), and PRP activation (47%). No significant difference among the 3 MIBO groups was found for the item scores except for the reporting of the recipient details (P = .012).

CONCLUSION

This study highlights the deficiencies in adherence to the MIBO guidelines, particularly in reporting key variables such as whole-blood characteristics, platelet recovery rate, PRP analysis, and PRP activation. These findings suggest that the publication of the MIBO guidelines has not resulted in improved reporting practices in studies investigating intra-articular PRP for the treatment of knee osteoarthritis.

PRP Injections for the Treatment of Knee Osteoarthritis: The Improvement Is Clinically Significant and Influenced by Platelet Concentration: A Meta-analysis of Randomized Controlled Trials

BACKGROUND

Platelet-rich plasma (PRP) has emerged as a promising therapeutic intervention for knee osteoarthritis (OA), attracting substantial clinical and research attention. However, the clinical relevance of the treatment benefit remains controversial.

PURPOSE

To evaluate the effectiveness of PRP compared with placebo in patients with knee OA in terms of minimal clinically important difference (MCID) and to investigate the possible influence of platelet concentration on the clinical outcome.

STUDY DESIGN

Meta-analysis. Level of evidence 1.

METHODS

The search was conducted on 5 databases (PubMed, Cochrane Library, Scopus, Embase, Web of Science) using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Inclusion criteria were randomized controlled trials comparing PRP and placebo injections to treat knee OA, written in the English language, with no time limitation. The effects were quantified at 1-, 3-, 6-, and 12-month follow-up points. Visual analog scale (VAS) for pain and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were used, with subanalyses based on platelet concentration performed using a 1,000,000 ± 20% platelets/µL cutoff. The MCID values (VAS, 1.37; WOMAC, 6.4) were used to interpret clinical improvement. The articles' quality was assessed using the Revised Tool for Risk of Bias in Randomized Trials and the Grading of Recommendations Assessment, Development and Evaluation guidelines.

RESULTS

Among the 5499 articles retrieved, 18 randomized controlled trials (1995 patients) were included. PRP presented statistically superior improvements in VAS and WOMAC scores compared with placebo at all follow-up points, exceeding the MCID at 3- and 6-month follow-up points for VAS and at all follow-up points for WOMAC. The subanalysis based on platelet concentration showed that high-platelet PRP provided clinically significant pain relief with the improvement exceeding the MCID compared with placebo at 3-, 6-, and 12-month follow-up points. In contrast, low-platelet PRP failed to offer a clinically perceivable benefit in terms of VAS score. WOMAC results showed that both products provided a clinically significant improvement at 3 and 6 months of follow-up. This benefit was maintained up to the 12-month follow-up in the high-platelet group but not in the low-platelet group, where the improvement compared with placebo did not reach statistical significance.

CONCLUSION

This meta-analysis showed that PRP offered clinically relevant functional improvement at 1-, 3-, 6-, and 12-month follow-up points and pain relief at 3- and 6-month follow-up points compared with placebo for the treatment of knee OA. Platelet concentration was found to influence treatment efficacy, with high-platelet PRP providing superior pain relief and more durable functional improvement compared with low-platelet PRP.

Platelet-rich plasma: A bibliometric and visual analysis from 2000 to 2022

BACKGROUND

Platelet-rich plasma (PRP) is an integral biotherapeutic modality with evolving significance in the medical domain. Despite its expanding applications, a comprehensive bibliometric evaluation is essential to understand its development and impact.

METHODS

The Web of Science core collection subject search identified articles pertinent to PRP applications. Analytical tools, including CiteSpace, VOSviewer, Bibliometrix (R-Tool for R-Studio), TBtools, SCImago Graphica, Origin, and Excel, facilitated the bibliometric scrutiny. This examination spanned dimensions ranging from geographical and institutional contributions to thematic shifts and keyword prevalence.

RESULTS

A corpus of 5167 publications was analyzed, with the United States, particularly the Hospital for Special Surgery, emerging as major contributors. The American Journal of Sports Medicine was identified as the primary journal, and Anitua Eduardo as the leading author in the domain. Keyword analysis highlighted evolving research themes, with a shift from traditional applications in orthopedics and dentistry to emerging areas such as dermatology, aesthetics, and chronic pain management.

CONCLUSION

The bibliometric analysis of PRP research reveals a multifaceted array of applications across various medical disciplines and highlights areas requiring further exploration, particularly in standardization, personalization, and safety. Future advancements in PRP research will necessitate innovative exploration, ethical considerations, and rigorous scientific validation to fully harness the therapeutic potential of PRP and related therapies.

Intra-articular corticosteroid injections versus platelet-rich plasma as a treatment for cervical facetogenic pain: a randomized clinical trial

OBJECTIVE

The study's primary objective was to compare the effectiveness of intra-articular platelet-rich plasma injections versus corticosteroid injections for the treatment of cervical facetogenic pain. Secondary aims were to compare self-rated disability, pain self-efficacy, and the safety of the procedure between groups.

METHODS

A single-site randomized double-blind controlled trial with 40 participants assigned to receive either leucocyte-poor, low-concentrate platelet-rich plasma injections or corticosteroid injection without local anesthetic into the cervical facet joint under fluoroscopy. Outcomes were collected via telephone at 1, 3, and 6 months to determine treatment effectiveness.

RESULTS

Low-concentrate platelet-rich plasma and corticosteroid injections had similar effects on cervical facetogenic pain intensity over a 6-month period post injection as demonstrated by a non-significant group-by-time interaction for Numeric Rating Scale scores (p>0.05). However, both groups showed a statistically significant decrease in cervical facetogenic pain intensity 1 month post treatment compared with baseline (p=0.02), while the platelet-rich plasma group also demonstrated a clinically significant decrease in pain intensity at the same time point. There was a significant interaction at 1 month post intervention for pain self-efficacy (p=0.04), with the platelet-rich plasma injection group showing a larger increase in pain self-efficacy compared with the corticosteroid injection group. No significant interaction was observed for self-rated disability; however, significant reductions were shown at 3 and 6 months post treatment compared with baseline in both groups (p<0.01). No significant differences between groups were reported for adverse events; however, those receiving platelet-rich plasma injection reported significantly less procedural pain (p=0.02).

CONCLUSION

Both platelet-rich plasma and corticosteroid injections induced similar improvements in cervical facetogenic pain intensity (1 month post) and self-rated disability (3 and 6 months post). Pain self-efficacy demonstrated a significant interaction with platelet-rich plasma injection showing greater improvement 1 month post. Additionally, both treatments exhibited a similar low prevalence of adverse events; however, those receiving platelet-rich plasma injection reported less procedural pain.

Influence of Platelet Concentration on the Clinical Outcome of Platelet-Rich Plasma Injections in Knee Osteoarthritis

BACKGROUND

Platelet-rich plasma (PRP) is one of the most frequently used orthobiologic products for the injection treatment of patients affected by knee osteoarthritis (OA). Some preliminary evidence supports the influence of platelet concentration on patients' clinical outcomes.

PURPOSE

To analyze if platelet concentration can influence the safety and clinical efficacy of PRP injections for the treatment of patients with knee OA.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This study consisted of 253 patients with knee OA (142 men, 111 women; mean ± SD age, 54.8 ± 11.4 years; Kellgren-Lawrence grades 1-3) who were treated with 3 intra-articular injections of 5 mL of autologous leukocyte-rich or leukocyte-poor PRP. All patients were prospectively evaluated at baseline and at 2, 6, and 12 months. Patients were clinically assessed thorough the Knee injury and Osteoarthritis Outcome Score (KOOS) subscales and the International Knee Documentation Committee (IKDC) Subjective score. Platelet concentration was correlated with clinical outcome. Further analysis was performed by stratifying patients into 3 groups (homogeneous for OA severity) based on platelet concentration (high, medium, and low). All complications and adverse events were reported, as well as failures.

RESULTS

An overall statistically significant improvement in all clinical scores was documented from baseline to each follow-up evaluation. Platelet concentration positively correlated with clinical outcome. KOOS Pain improved more with higher platelet concentration at 2 months (P = .036; rho = 0.132), 6 months (P = .009; rho = 0.165), and 12 months (P = .014; rho = 0.155). The same trend was shown by the other KOOS subscales and by the IKDC Subjective score, as well as by the comparison of the groups of high-, medium-, and low-platelet PRP. The highest failure rate (15.0%) was found in the low-platelet group as compared with the medium-platelet group (3.3%) and the high-platelet group (3.3%). No differences were observed among the 3 groups in terms of adverse events.

CONCLUSION

This study demonstrated that platelet concentration influences the clinical outcome of PRP injections in knee OA treatment. PRP with a higher platelet concentration provides a lower failure rate and higher clinical improvement as compared with PRP with a lower platelet concentration, with overall better results up to 12 months of follow-up in patients with knee OA.

Leukocytes Do Not Influence the Safety and Efficacy of Platelet-Rich Plasma Injections for the Treatment of Knee Osteoarthritis: A Double-Blind Randomized Controlled Trial

BACKGROUND

Platelet-rich plasma (PRP) is increasingly used for the injection treatment of knee osteoarthritis (OA). However, the role of leukocytes contained in PRP is controversial, with some preclinical studies suggesting detrimental effects and others emphasizing their contribution in secreting bioactive molecules.

PURPOSE

To compare the safety and effectiveness of leukocyte-rich PRP (LR-PRP) and leukocyte-poor PRP (LP-PRP) for the treatment of knee OA.

HYPOTHESIS

That leukocytes could influence results both in terms of adverse events and clinical outcomes.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

This double-blind randomized controlled trial included 132 patients with Kellgren-Lawrence grade 1-3 knee OA who were randomized to a 3-injection cycle of either LR-PRP or LP-PRP. Patients were prospectively assessed at baseline and at 2, 6, and 12 months with subjective evaluations comprising the International Knee Documentation Committee (IKDC) subjective score, the KOOS (Knee injury and Osteoarthritis Outcome Score), the WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index), the visual analog scale for pain, the EuroQol-visual analog scale, the EuroQol-5 dimensions, and the Tegner activity scale. Objective evaluations consisted of the IKDC objective score, active/passive range of motion, and circumference of the index and contralateral knees. Patient judgment of the treatment was recorded as well as adverse reactions and failures.

RESULTS

An overall improvement in subjective and objective outcomes was documented, with no differences between the 2 groups, except for the improvement in the IKDC subjective score at 2 months, which was greater for the LR-PRP group compared with the LP-PRP group (14.8 ± 14.8 vs 8.6 ± 13.3, respectively; P = .046), as well as for active (P = .021) and passive (P = .040) ROM of the index knee at 6 months, showing statistically significant higher values in the LP-PRP group; and for quadriceps circumference of the index (P = .042) and contralateral (P = .045) knees at 12 months, which were significantly greater in the LR-PRP group. The IKDC subjective score improved from 42.5 ± 17.6 at baseline to 55.6 ± 21.4 at 12 months for the LR-PRP group (P < .0005) and from 45.7 ± 16.4 to 55.3 ± 20.4 for the LP-PRP group (P = .001). No differences in terms of patient treatment judgment were observed at all follow-up time points. No severe adverse events related to the treatment were reported, but some mild adverse events related to the treatment were observed: 16 in the LR-PRP group and 17 in the LP-PRP group. Treatment failed in 5 patients in the LR-PRP group and 2 in the LP-PRP group.

CONCLUSION

This double-blind randomized controlled trial demonstrated that leukocytes did not affect the safety and efficacy of intra-articular PRP injections for the treatment of patients with knee OA. Both LR-PRP and LP-PRP demonstrated comparable clinical outcomes at all follow-up time points, without showing differences in subjective and objective outcomes or in adverse events and treatment failures.

REGISTRATION

NCT04187183 (ClinicalTrials.gov).

Leukocyte Platelet-Rich Plasma-Derived Exosomes Restrained Macrophages Viability and Induced Apoptosis, NO Generation, and M1 Polarization

BACKGROUND

Chronic refractory wounds refer to wounds that cannot be repaired timely. Platelet-rich plasma (PRP) has significant potential in chronic wound healing therapy. The exosomes isolated from PRP were proved to exhibit more effectiveness than PRP. However, the therapeutic potential of exosomes from PRP on chronic refractory wounds remained elusive. Hence, this study aimed to clarify the action of exosomes from PRP on chronic refractory wounds by evaluating the response of macrophages to exosomes.

METHODS

Pure platelet-rich plasma (P-PRP) and leukocyte platelet-rich plasma (L-PRP) were prepared from the fasting venous blood of healthy volunteers. Exosomes were extracted from P-PRP and L-PRP using ultracentrifugation and identified by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and western blot. Macrophages were obtained by inducing THP-1 cells with phorbol-12-myristate-13 acetate (PMA). The internalization of exosomes into macrophages was observed utilizing confocal laser scanning microscopy after being labeled with PKH67. Cell viability was determined by CCK-8 assay. Cell apoptosis was measured utilizing a flow cytometer. The polarization status of M1 and M2 macrophages were evaluated by detecting their markers. Nitric oxide (NO) detection was conducted using the commercial kit.

RESULTS

Exosomes from P-PRP and L-PRP were absorbed by macrophages. Exosomes from L-PRP restrained viability and induced apoptosis of macrophages. Besides, exosomes from P-PRP promoted M2 polarization, and exosomes from L-PRP promoted M1 polarization. Furthermore, exosomes from L-PRP promoted NO generation of macrophages.

CONCLUSION

Exosomes from L-PRP restrained viability, induced apoptosis and NO generation of macrophages, and promoted M1 polarization, while exosomes from P-PRP increased M2 polarization. The exosomes from L-PRP presented a more effective effect on macrophages than that from P-PRP, making it a promising strategy for chronic refractory wound management.

iPSC-derived megakaryocytes and platelets accelerate wound healing and angiogenesis

BACKGROUND

Platelet-rich plasma (PRP), which is prepared by concentrating platelets in autologous blood, shows efficacy in chronic skin wounds via multiple growth factors. However, it exhibits heterogeneity across patients, leading to unstable therapeutic efficacy. Human induced pluripotent stem cell (iPSC)-derived megakaryocytes and platelets (iMPs) are capable of providing a stable supply, holding promise as materials for novel platelet concentrate-based therapies. In this context, we evaluated the effect of iMPs on wound healing and validated lyophilization for clinical applications.

METHODS

The growth factors released by activated iMPs were measured. The effect of the administration of iMPs on human fibroblasts and human umbilical vein endothelial cells (HUVECs) was investigated in vitro. iMPs were applied to dorsal skin defects of diabetic mice to assess the wound closure rate and quantify collagen deposition and angiogenesis. Following the storage of freeze-dried iMPs (FD-iMPs) for three months, the stability of growth factors and their efficacy in animal models were determined.

RESULT

Multiple growth factors that promote wound healing were detected in activated iMPs. iMPs specifically released FGF2 and exhibited a superior enhancement of HUVEC proliferation compared to PRP. Moreover, an RNA-seq analysis revealed that iMPs induce polarization to stalk cells and enhance ANGPTL4 gene expression in HUVECs. Animal studies demonstrated that iMPs promoted wound closure and angiogenesis in chronic wounds caused by diabetes. We also confirmed the long-term stability of growth factors in FD-iMPs and their comparable effects to those of original iMPs in the animal model.

CONCLUSION

Our study demonstrates that iMPs promote angiogenesis and wound healing through the activation of vascular endothelial cells. iMPs exhibited more effectiveness than PRP, an effect attributed to the exclusive presence of specific factors including FGF2. Lyophilization enabled the long-term maintenance of the composition of the growth factors and efficacy of the iMPs, therefore contributing to stable supply for clinical application. These findings suggest that iMPs provide a novel treatment for chronic wounds.

Comparison of functional performance outcomes between oral patented crystalline glucosamine sulfate and platelet-rich plasma among knee osteoarthritis patients: a propensity score matching analysis

BACKGROUND

Among the medications used to treat knee osteoarthritis (OA), oral patented crystalline glucosamine sulfate (pCGS) and platelet-rich plasma (PRP) have become popular alternatives to painkillers or nonsteroidal anti-inflammatory drugs (NSAIDs). Although studies have shown that pCGS and PRP improve clinical outcomes, no study has compared outcomes between these optional treatments. We compared functional performance outcomes from baseline to the 1-year follow-up (FU) between oral pCGS and PRP in patients with knee OA.

MATERIALS AND METHODS

Three hundred eighty-two patients receiving oral pCGS and 122 patients receiving PRP injections were enrolled for a review of functional performance outcomes, including a five-time sit-to-stand test (5xSST), time up-and-go test (TUGT), and 3-minute walk distance test (3MWDT). The patients were followed up for one year. The pCGS group received 1500 mg daily, whereas the PRP group received 2 cycles of intra-articular injections at week 0 and week 6. Using propensity score matching based on age, sex, height, weight, BMI, and Kellgren and Lawrence (KL) classification, all three functional performance outcomes were compared between the baseline (pretreatment), 6-week, 12-week, 24-week, and 1-year FUs.

RESULTS

With a ratio of 2:1 (pCGS: PRP), 204 patients in the pCGS group were matched with 102 patients in the PRP group. Compared with the baseline levels, the PRP group showed significant improvements in 5xSST and TUGT outcomes from 6 weeks and significant improvements in 3MWDT outcomes from 12 weeks, whereas the pCGS group showed significant improvements in TUGT outcomes from 6 weeks and significant improvements in 5xSST and 3MWDT outcomes from 12 weeks. At the 24-week and 1-year FU, both groups showed significant improvements in all three functional performance tests without adverse events.

CONCLUSIONS

Although the PRP group showed faster improvements in 5xSST outcomes at six weeks, from the 12-week to 1-year FU, both the pCGS and PRP groups showed significant improvements in 5xSST, TUGT, and 3MWDT outcomes. As the use of PRP is more complicated and invasive than the use of oral pCGS, the benefits and drawbacks of selecting PRP over pCGS in knee OA treatment should be examined.

A primer on the restorative therapies for erectile dysfunction: a narrative review

INTRODUCTION

Erectile dysfunction (ED) is a common condition that affects millions worldwide. Patients and urologists alike are seeking alternative therapies that can provide long-lasting results in the treatment of ED. This review provides a comprehensive overview of restorative treatments available for ED, such as platelet-rich plasma, stem cell therapy, and shockwave therapy.

OBJECTIVE

The aim of this narrative review is to provide a primer for urologists and general practitioners on the basics of implementing ED restorative therapies in their practice.

METHODS

The PubMed, MEDLINE, and Google Scholar databases were searched for articles in the English language through August 31, 2023, that included key terms such as "erectile dysfunction," "restorative therapy," "shockwave therapy," "platelet-rich plasma," "stem cell therapy," and "stromal vascular fraction." Reference lists of selected studies were manually reviewed to find articles not identified by the initial database search.

RESULTS

Shockwave therapy has demonstrated effectiveness in treating ED, with devices like the Medispec ED1000 and Storz Duolith showing statistically significant improvements in patient scores for International Index of Erectile Function (IIEF)-Erectile Function scores in clinical trials. In reported studies of platelet-rich plasma injections, a substantial percentage of patients reached a minimal clinically important difference in the IIEF-Erectile Function scale after treatment. Studies of ED treatment with stem cell therapy, while limited and with small sample sizes, have demonstrated encouraging improvements in patient scores for the abridged 5-item version of the IIEF after treatment.

CONCLUSION

Shockwave, platelet-rich plasma, and stem cell therapies are important, novel, noninvasive restorative treatments for ED that can provide relief for patients wishing to avoid a more invasive approach. While these therapies have shown promising results in clinical trials, more research is required to establish them as standardized and efficacious options in the management of ED.

Mechanical loading and orthobiologic therapies in the treatment of post-traumatic osteoarthritis (PTOA): a comprehensive review

The importance of mechanical loading and its relationship to orthobiologic therapies in the treatment of post-traumatic osteoarthritis (PTOA) is beginning to receive attention. This review explores the current efficacy of orthobiologic interventions, notably platelet-rich plasma (PRP), bone marrow aspirate (BMA), and mesenchymal stem/stromal cells (MSCs), in combating PTOA drawing from a comprehensive review of both preclinical animal models and human clinical studies. This review suggests why mechanical joint loading, such as running, might improve outcomes in PTOA management in conjunction with orthiobiologic administration. Accumulating evidence underscores the influence of mechanical loading on chondrocyte behavior and its pivotal role in PTOA pathogenesis. Dynamic loading has been identified as a key factor for optimal articular cartilage (AC) health and function, offering the potential to slow down or even reverse PTOA progression. We hypothesize that integrating the activation of mechanotransduction pathways with orthobiologic treatment strategies may hold a key to mitigating or even preventing PTOA development. Specific loading patterns incorporating exercise and physical activity for optimal joint health remain to be defined, particularly in the clinical setting following joint trauma.

Platelet-Rich Fibrin Increases CXCL8 Expression in Gingival Fibroblasts

Platelet-rich fibrin (PRF), the coagulated plasma of fractionated blood, is widely used to support tissue regeneration in dentistry, and the underlying cellular and molecular mechanisms are increasingly being understood. Periodontal connective tissues steadily express CXCL8, a chemokine that attracts granulocytes and lymphocytes, supporting homeostatic immunity. Even though PRF is considered to dampen inflammation, it should not be ruled out that PRF increases the expression of CXCL8 in gingival fibroblasts. To test this hypothesis, we conducted a bioassay where gingival fibroblasts were exposed to PRF lysates and the respective serum. We show here that PRF lysates and, to a lesser extent, PRF serum increased the expression of CXCL8 by the gingival fibroblasts, as confirmed by immunoassay. SB203580, the inhibitor of p38 mitogen-activated protein kinase, reduced CXCL8 expression. Consistently, PRF lysates and, to a weaker range, the PRF serum also caused phosphorylation of p38 in gingival fibroblasts. Assuming that PRF is a rich source of growth factors, the TGF-β receptor type I kinase inhibitor SB431542 decreased the PRF-induced expression and translation of CXCL8. The findings suggest that PRF lysates and the respective serum drive CXCL8 expression by activating TGF-β and p38 signaling in gingival fibroblasts.

The varying clinical effectiveness of single, three and five intraarticular injections of platelet-rich plasma in knee osteoarthritis

OBJECTIVE

To investigate the variations in clinical effectiveness among patients diagnosed with knee osteoarthritis who underwent intra-articular administration of platelet-rich plasma using single, triple, or quintuple injections.

METHODS

One hundred twenty patients with grade I-III knee osteoarthritis were randomly assigned to three groups: PRP1 group, who received a single injection of platelet-rich plasma; PRP3 group, who received three PRP injections one week apart; PRP5 group, who received five PRP injections one week apart. The patients' conditions were evaluated using the Visual Analogue Scale (VAS) and the Western Ontario and McMaster Universities Arthritis Index-VA3.1 version (WOMAC-VA3.1) at baseline and 6, 12, 24, and 52 weeks 52 weeks follow up.

RESULTS

Out of the total participants, 106 patients (30 males and 76 females) completed the study. The primary outcome measure, WOMAC pain score, registered significant improvements across all groups when compared to pre-treatment levels. However, the application of 3 and 5 injections of platelet-rich plasma was substantially more effective than that of a single injection in reducing knee pain and stiffness, as well as enhancing physical function in patients with knee osteoarthritis. No statistically discernable difference was observed between PRP3 and PRP5 at all follow-up intervals, and there was no discernable difference between 3 and 5 PRP injections either. Mild side effects occurred in all three groups.

CONCLUSIONS

The administration of three or five injections of platelet-rich plasma is safe, substantially more effective than single injections, and leads to remarkable clinical improvement by significantly reducing knee pain, improving joint stiffness, and enhancing physical function in patients with grade I-III knee osteoarthritis. Furthermore, no significant difference was observed in the efficacy of three or five injections. Therefore, we recommend using three injections of PRP in the treatment of patients with knee osteoarthritis of grade I-III.

Cellular composition modifies the biological properties and stability of platelet rich plasma membranes for tissue engineering

Scaffolds should provide structural support for tissue regeneration, allowing their gradual biodegradation and interacting with cells and bioactive molecules to promote remodeling. Thus, the scaffold's intrinsic properties affect cellular processes involved in tissue regeneration, including migration, proliferation, differentiation, and protein synthesis. In this sense, due to its biological effect and clinical potential, Platelet Rich Plasma (PRP) fibrin could be considered a successful scaffold. Given the high variability in commercial PRPs formulations, this research focused on assessing the influence of cellular composition on fibrin membrane stability and remodeling cell activity. The stability and biological effect were evaluated at different time points via D-dimer, type I collagen and elastase quantification in culture media conditioned by Plasma Rich in Growth Factors - Fraction 1 (PRGF-F1), Plasma Rich in Growth Factors - Whole Plasma (PRGF-WP) and Leukocyte-rich Platelet Rich Plasma (L-PRP) membranes, and by gingival fibroblast cells seeded on them, respectively. Ultrastructure of PRP membranes was also evaluated. Histological analyses were performed after 5 and 18 days. Additionally, the effect of fibrin membranes on cell proliferation was determined. According to the results, L-PRP fibrin membranes degradation was complete at the end of the study, while PRGF membranes remained practically unchanged. Considering fibroblast behavior, PRGF membranes, in contrast to L-PRP ones, promoted extracellular matrix biosynthesis at the same time as fibrinolysis and enhanced cell proliferation. In conclusion, leukocytes in PRP fibrin membranes drastically reduce scaffold stability and induce behavioral changes in fibroblasts by reducing their proliferation rate and remodeling ability.

Adipose Tissue-Derived Products May Present Inflammatory Properties That Affect Chondrocytes and Synoviocytes from Patients with Knee Osteoarthritis

Adipose tissue-derived cell-based injectable therapies have been demonstrated to have disease-modifying effects on joint tissues in preclinical studies on animal osteoarthritis (OA) models, but clinical results are heterogeneous and not always satisfactory. The aim of this study was to investigate the influence of adipose tissue properties on the therapeutic effects of the adipose-derived product in an in vitro OA setting. Micro-fragmented adipose tissue (MF-AT) samples were obtained from 21 OA patients (mean age 51.7 ± 11.8 years, mean BMI 25.7 ± 4.1 kg/m2). The analysis of the MF-AT supernatant was performed to analyze the release of inflammatory factors. The effects of MF-AT inflammatory factors were investigated on chondrocytes and synoviocytes gene expression levels. Patients' characteristics were analyzed to explore their influence on MF-AT inflammatory molecules and on the MF-AT effects on the gene expression of chondrocytes and synoviocytes. The study results demonstrated that adipose tissue-derived products may present inflammatory properties that influence the therapeutic potential for OA treatment, with products with a higher pro-inflammatory profile stimulating a higher expression of genes related to a more inflamed and catabolic phenotype. A higher pro-inflammatory cytokine pattern and a higher pro-inflammatory effect were found in adipose tissue-derived products obtained from OA patients with higher BMI.

Office-Based Intraosseous Infiltrations of PRGF as an Effective Treatment for Knee Osteoarthritis: A Retrospective Observational Clinical Study

The aim of this study was to explore and assess office-based ultrasound-guided intraosseous and intra-articular infiltrations of plasma rich in growth factors (PRGF) in patients with moderate and severe knee osteoarthritis (KOA). Seventy-nine patients (30 women and 49 men) with grade 3-4 KOA according to the Kellgren-Lawrence classification participated in the study. All patients were treated with a minimally invasive technique using local anesthesia WALANT (wide-awake local anesthesia no tourniquet) in the ambulatory setting. A PRGF intra-articular infiltration and two intraosseous infiltrations in the tibial plateau and femoral condyle were performed weekly for a total of three sessions. The evaluation of the results was carried out using knee injury and osteoarthritis outcome score (KOOS) at baseline and post-treatment. After a follow-up period of 11 months (median) [interquartile range, 7-14], all the KOOS domains showed statistically significant improvement (p < 0.001). Moreover, 88% of the patients showed a pain reduction of at least 10 points (minimally clinically important improvement) from pre- to post-treatment. Our retrospective study using the in-office procedure of ultrasound-guided combination of intra-articular and intraosseous infiltrations of PRGF is a safe and efficacious approach for the treatment of grade 3-4 knee osteoarthritis.

Leukocyte-Rich Platelet-Rich Plasma Is Predominantly Anti-inflammatory Compared With Leukocyte-Poor Platelet-Rich Plasma in Patients With Mild-Moderate Knee Osteoarthritis: A Prospective, Descriptive Laboratory Study

BACKGROUND

Platelet-rich plasma (PRP) has been used extensively in clinical practice to treat patients with symptomatic knee osteoarthritis (OA). Leukocyte-poor PRP (LP-PRP) has been clinically preferred over leukocyte-rich PRP (LR-PRP); however, it is unclear which cytokine mediators of pain and inflammation are present in LR-PRP and LP-PRP from patients with mild to moderate knee OA in order to rationalize a specific formulation.

HYPOTHESIS

LP-PRP would be predominantly anti-inflammatory and have reduced nociceptive pain mediators compared with LR-PRP from the same individual with mild to moderate knee OA.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 24 unique samples of PRP were prepared in order to assess 48 samples of LR-PRP and LP-PRP taken from 12 patients (6 male and 6 female) with symptomatic knee OA of Kellgren-Lawrence grade 2 to 3. Patients underwent blood collection for LR-PRP and LP-PRP preparation through a double-spin protocol to obtain baseline whole blood, platelet concentration, and white blood cell subtypes. LR-PRP and LP-PRP from the same patient were produced at the same time and underwent a comprehensive panel through Luminex (multicytokine profiling) to assess key mediators of inflammation: interleukin 1 receptor antagonist (IL-1Ra), interleukin 4, 6, 8, and 10 (IL-4, IL-6, IL-8, and IL-10), IL-1β, tissue necrosis factor α (TNF-α), and matrix metalloproteinase 9 (MMP-9). To assess mediators of nociceptive pain, nerve growth factor (NGF) and tartrate resistant acid phosphatase 5 (TRAP5) were also assessed.

RESULTS

LR-PRP from patients with mild to moderate knee OA expressed significantly more IL-1Ra, IL-4, IL-8, and MMP-9 compared with LP-PRP formulations from the same patients. No significant differences were found between LR-PRP and LP-PRP in mediators of nociceptive pain-namely, NGF and TRAP5. Other mediators including TNF-α, IL-1β, IL-6, and IL-10 were also found to have no significant expression differences between LR-PRP and LP-PRP.

CONCLUSION

LR-PRP expressed significantly more IL-1Ra, IL-4, and IL-8, suggesting that LR-PRP may be more anti-inflammatory than LP-PRP. MMP-9 was expressed in higher concentrations in LR-PRP, suggesting that LR-PRP may be more chondrotoxic than LP-PRP.

CLINICAL RELEVANCE

LR-PRP was found to have a robust expression of anti-inflammatory mediators compared with LP-PRP and may be beneficial to patients with long-term knee OA where chronic low-grade inflammation is present. Mechanistic clinical trials are needed to elucidate the key mediators in both LR-PRP and LP-PRP to assess their effect on long-term progression of knee OA.

Platelet-Rich Plasma for Knee Osteoarthritis: What Does the Evidence Say?

The utilization of platelet-rich-plasma as a therapeutic intervention for knee osteoarthritis has gained immense attention since 2008. The increase in the number of scientific publications dedicated to this area can be attributed to the majority of favorable results reported in clinical trials and basic science studies. However, despite the growing evidence, the use of platelet-rich plasma in clinical practice still poses controversial aspects. The potential mechanisms of action described for platelet-rich-plasma so far indicate that it could serve as a disease-modifying drug, acting to counteract important aspects of knee osteoarthritis pathophysiology (cartilage breakdown, inflammation, and bone remodeling). Nevertheless, its efficacy in slowing down the progression of knee osteoarthritis remains unproven. While inconsistencies have been noted, the majority of controlled clinical trials and meta-analyses advocate for the utilization of platelet-rich-plasma in treating knee osteoarthritis, as it has demonstrated greater efficacy than hyaluronic acid and placebo, with a follow-up of at least 1 year. Despite advancements made in certain areas, significant diversity persists regarding the formulations used, therapeutic regimen, extended follow-up periods, patient selection, and assessment of clinically relevant outcomes. Consequently, the leading clinical practice guidelines do not recommend its use. In light of the emerging evidence, this narrative review aims to provide an objective evaluation of the recent available scientific literature (last 5 years) focused on randomized clinical trials and meta-analyses to present a current overview of the topic.

Pseudoseptic reaction to an intra-articular platelet-rich plasma injection into the knee: a case report

A variety of intra-articular injections are used for the management of osteoarthritis. A rare complication of intra-articular injections is acute pseudoseptic arthritis, which mimics true septic arthritis. To the authors knowledge, pseudosepsis has not been reported as a complication after platelet-rich plasma (PRP) injections. We present a case report of pseudoseptic arthritis resulting in acute postinjection pain and a joint effusion after an intra-articular PRP injection into the knee. Clinically, pseudosepsis can occur after PRP treatment with significantly elevated white blood cell counts in the synovial fluid, and should be a consideration in cases of post-PRP injection flares.

Clinical results of autologous protein solution injection for knee osteoarthritis with severe disease grade is inferior to mild or moderate grade

Autologous protein solution (APS) is made from platelet-rich plasma that extracts high-concentration growth factors and cytokines. Intra-articular APS injection was reported to improve knee osteoarthritis (KOA) pain and function. However, efficacy differences regarding osteoarthritis severity remained unknown. This retrospective study clinically assessed 220 knees with KOA in the Kellgren-Lawrence (KL) grades 2-4 that underwent APS injection using the Knee Injury and Osteoarthritis Outcome Score (KOOS). A telephone survey was performed for patients who dropped out to check symptom changes. The recalculated estimated responder rate included the telephone survey results. The 12-month follow-up was completed with 148 knees (67%), whereas 72 knees dropped out. The follow-up rate was significantly lower in KL4 than KL2 and 3. The KOOS significantly improved in 148 knees, whereas the KOOS was lower in KL4 than in KL2. The responder rate was 55% total, 58% in KL2, 57% in KL3, and 47% in KL4; however, the estimated responder rate, including the telephone survey, was 49% total, 55% in KL2, 54% in KL3, and 36% in KL4. This study showed improved clinical symptoms 1-year after APS injections for KOA, with a lower responder rate in KL4 than in KL2 or KL3.

The Efficacy of Microfracture Combined with Extracorporeal Shock Wave Therapy for Treating Osteochondral Lesion of the Talus and the Quality of Regenerated Cartilage: A Retrospective Cohort Study and MRI Assessment

BACKGROUND

osteochondral lesion of the talus (OLT) is a common disease in the physically active population, and extracorporeal shock wave therapy (ESWT) is a noninvasive treatment. We hypothesized that microfracture (MF) combined with ESWT may have great potential to become a novel combination treatment of OLT.

METHODS

the OLT patients who received MF + ESWT or MF + platelet-rich plasma (PRP) injection were retrospectively included, with a minimal follow up of 2y. The daily activating VAS, exercising VAS, and American Orthopedic Foot and Ankle Society Ankle-Hindfoot Score (AOFAS) were used to assess the efficacy and functional outcome, and ankle MRI T2 mapping was used to evaluate the quality of regenerated cartilage in the OLT patients.

RESULTS

only transient synovium-stimulated complications were found during the treatment sessions; the complication rate and daily activating VAS did not have differences between groups. MF + ESWT had a higher AOFAS and a lower T2 mapping value than MF + PRP at the 2y follow up.

CONCLUSIONS

the MF + ESWT had superior efficacy for treating OLT, which resulted in better ankle function and more hyaline-like regenerated cartilage, superior to the traditional MF + PRP.

Autologous Platelet and Extracellular Vesicle-Rich Plasma as Therapeutic Fluid: A Review

The preparation of autologous platelet and extracellular vesicle-rich plasma (PVRP) has been explored in many medical fields with the aim to benefit from its healing potential. In parallel, efforts are being invested to understand the function and dynamics of PVRP that is complex in its composition and interactions. Some clinical evidence reveals beneficial effects of PVRP, while some report that there were no effects. To optimize the preparation methods, functions and mechanisms of PVRP, its constituents should be better understood. With the intention to promote further studies of autologous therapeutic PVRP, we performed a review on some topics regarding PVRP composition, harvesting, assessment and preservation, and also on clinical experience following PVRP application in humans and animals. Besides the acknowledged actions of platelets, leukocytes and different molecules, we focus on extracellular vesicles that were found abundant in PVRP.

Effects of Conditioned Medium of Adipose-Derived Stem Cells Exposed to Platelet-Rich Plasma on the Expression of Endothelial Nitric Oxide Synthase and Angiogenesis by Endothelial Cells

ABSTRACT

Platelet-rich plasma (PRP) and adipose-derived stem cells (ADSCs) are known to secrete angiogenic factors that contribute to the treatment of intractable ulcers. The combination of PRP and ADSCs may enhance their angiogenic effects. However, it remains unclear whether treatment of ADSCs with PRP influences angiogenesis. We studied whether the conditioned medium from PRP-treated ADSCs under hypoxic conditions exerts angiogenic effects. Although PRP stimulated the proliferation of ADSCs obtained from rats, it decreased the mRNA levels of vascular endothelial growth factor, hepatocyte growth factor, and TGF-β1, but not of basic fibroblast growth factor, under hypoxia. The conditioned medium of PRP-treated ADSCs inhibited endothelial nitric oxide synthase phosphorylation, decreased NO production, and suppressed tube formation in human umbilical vein endothelial cells. Transplantation of ADSCs alone increased both blood flow and capillary density of the ischemic limb; however, its combination with PRP did not further improve blood flow or capillary density. This suggests that both conditioned medium of ADSCs treated with PRP and combination of PRP with ADSCs transplantation may attenuate the phosphorylation of endothelial nitric oxide synthase and angiogenesis.

Pure Platelet and Leukocyte-Platelet-Rich Plasma for Regenerative Medicine in Orthopedics-Time- and Preparation-Dependent Release of Growth Factors and Effects on Synovial Fibroblasts: A Comparative Analysis

Intra-articular injections of autologous platelet concentrates are considered capable to enhance the healing of cartilage lesions, alleviate joint inflammation, and relieve other musculoskeletal pathological conditions. The aim of this study was to analyze the soluble fractions obtained from platelet-rich plasma (pure- and leukocyte-PRP) to compare time- and preparation-dependent modifications of growth factor concentrations and the supporting activity of the two preparations on synovial fibroblast growth and hyaluronic acid (HA) production in vitro. The release kinetics of FGF-2, SDF-1, VEGF, HGF, EGF, PD GF-AB/BB, IGF-1, VCAM-1, and TGF-β isoforms were followed up to 168 h after PRP activation, and their amounts were determined by multiplex-beads immunoassay. Synovial cell growth and supernatant HA production were respectively analyzed by Alamar Blue assay and ELISA. Time-dependent modifications grouped molecules in three peculiar patterns: one reaching the highest concentrations within 18 h and decreasing afterwards, another progressively increasing up to 168 h, and the last peaking at the central time points. Synovial fibroblast growth in response to L-PRP and P-PRP revealed differences over time and among added concentrations. Both preparations displayed a preserved supporting capacity of HA synthesis.

Leukocyte-Rich vs. Leukocyte-Poor Platelet-Rich Plasma for the Treatment of Knee Osteoarthritis

Knee osteoarthritis (OA) is a well-established form of OA and accounts for nearly 4/5 of global OA burden […].

Platelet-Rich Plasma for Intra-articular Injections: Preclinical and Clinical Evidence

The use of platelet-rich plasma (PRP) has been supported by encouraging data from in vitro and preclinical in vivo studies, both in terms of safety and efficacy. This led to the wide use of PRP injections in the clinical practice, with promising results especially as a minimally invasive treatment for cartilage degeneration and osteoarthritis (OA). While many controversies remain on the best PRP formulation, the overall available clinical studies support the benefits of PRP, with functional improvement and reduction of pain-related symptoms up to 12 months, especially in young patients and early OA stages.

The Effects of Intra-Articular Platelet-Rich Plasma Injections in Rheumatoid Arthritis: A Narrative Review

Platelet-rich plasma injections have been a therapeutic option with exponential growth in several pathologies in the last decades, particularly musculoskeletal for their effect on improving pain and functionality. Rheumatoid arthritis is a chronic joint disease, which involves inflammation of the synovial membrane with cartilage and juxta-articular bone destruction. Conventional and biological disease-modifying anti-rheumatoid drugs are the cornerstone of the treatment of this disease. However, the use of intra-articular glucocorticoids is often necessary and the role of platelet-rich plasma injections in these patients remains uncertain.

A literature review was carried out through the PubMed database, Cochrane and Google Scholar for the search terms “rheumatoid arthritis” and “platelet-rich plasma”. Eleven studies have been included in this review: two of these are in vitro studies, five are animal studies, one case report, two case series and one randomized controlled trial. Most of the studies demonstrated a decrease in pain and inflammatory mediators and improvement of functional outcomes, with no severe adverse effects reported.

However, the quantity and quality of literature about the effects and safety of plasma-rich plasma injections in rheumatoid arthritis patients are still scarce. It is essential that well-designed randomized controlled trials are made on this topic to understand if platelet-rich plasma may be useful as a coadjuvant therapy in rheumatoid arthritis.

Umbilical Cord PRP vs. Autologous PRP for the Treatment of Hip Osteoarthritis

Umbilical cord platelet-rich plasma (C-PRP) has more growth factors and anti-inflammatory molecules compared with autologous PRP (A-PRP) derived from peripheral blood. The aim of this study was to compare intra-articular C-PRP or A-PRP injections in terms of safety and clinical efficacy for the treatment of patients with hip osteoarthritis (OA). This study investigated the results of 100 patients with hip OA treated with three weekly ultrasound-guided injections of either C-PRP or A-PRP. Clinical evaluations were performed before the treatment and after two, six, and twelve months with the HHS, WOMAC, and VAS scores. No major adverse events were recorded. Overall, the improvement was limited with both treatments. Significant improvements in VAS (p = 0.031) and HHS (p = 0.011) were documented at two months for C-PRP. Patients with a low OA grade (Tonnis 1-2) showed a significantly higher HHS improvement with C-PRP than A-PRP at twelve months (p = 0.049). C-PRP injections are safe but offered only a short-term clinical improvement. The comparative analysis did not demonstrate benefits compared with A-PRP in the overall population, but the results are influenced by OA severity, with C-PRP showing more benefits when advanced OA cases were excluded. Further studies are needed to confirm the most suitable indications and potential of this biological injective approach.

Leukocyte-Rich versus Leukocyte-Poor Platelet-Rich Plasma for the Treatment of Knee Osteoarthritis: A Double-Blind Randomized Trial

BACKGROUND

Platelet-rich plasma (PRP) is gaining large interest in clinical practice as a minimally invasive injective treatment for knee osteoarthritis (OA). Different preparation methods are available, and the presence of leukocytes, deemed detrimental in some preclinical studies, is one of the most debated aspects regarding PRP efficacy.

PURPOSE

To compare the safety and effectiveness of leukocyte-rich PRP (LR-PRP) and leukocyte-poor PRP (LP-PRP) for the treatment of knee OA.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 192 patients with symptomatic knee OA (Kellgren-Lawrence grade 1-3) were randomly allocated to 3 weekly injections of LR-PRP or LP-PRP. LP-PRP was obtained with a filter for leukodepletion. LR-PRP and LP-PRP were divided into aliquots of 5 mL, with a mean platelet concentration of 1146.8 × 10⁹/L and 1074.9 × 10⁹/L and a mean leukocyte concentration of 7991.4 × 10⁶/L and 0.1 × 10⁶/L, respectively. Patients were evaluated at baseline and thereafter at 2, 6, and 12 months for the primary outcome, the International Knee Documentation Committee (IKDC) subjective score; and for secondary outcomes, the Knee injury and Osteoarthritis Outcome Score (KOOS) subscales, EuroQol-visual analog scale (EQ-VAS), and Tegner score.

RESULTS

No differences between groups were observed in terms of absolute values or improvement of the clinical scores across all follow-up intervals. The mean IKDC subjective score at baseline and 12 months improved from 45.6 to 60.7 in the LR-PRP group as compared with 46.8 to 62.9 in the LP-PRP group (P = .626). No severe adverse events were described in either group, although 15 mild adverse events (knee pain or swelling) were reported: 12.2% for LR-PRP and 4.7% for LP-PRP (P = .101). No statistically significant difference was also found between LR-PRP and LP-PRP in terms of failures (7.8% vs 3.5%, P = .331).

CONCLUSION

This double-blind randomized trial showed that 3 intra-articular LR-PRP or LP-PRP injections produced similar clinical improvement in the 12 months of follow-up in patients with symptomatic knee OA. Both treatment groups reported a low number of adverse events, without intergroup differences. The presence of leukocytes did not significantly affect the clinical results of PRP injections.

REGISTRATION

NCT02923700 (ClinicalTrials.gov identifier).

Orthobiologics: Diagnosis and Treatment of Common Tendinopathies

Orthobiologics, including platelet-rich plasma, prolotherapy, and mesenchymal stem cells, are seeing increasing use in the treatment of osteoarthritis (OA), muscle injury, and tendinopathy. This article reviews the biology and applications of orthobiologics in tendons, muscles, and joints, and focuses on platelet-rich plasma (PRP). Clinical evidence-based literature related to the use of PRP in the treatment of rotator cuff injury, lateral epicondylosis, Achilles tendinopathy, plantar fasciitis, knee OA, and acute muscle injury are discussed.

Regenerative Potential of Platelet Concentrate Lysate in Mechanically Injured Cartilage and Matrix-Associated Chondrocyte Implantation In Vitro

Adjuvant therapy in autologous chondrocyte implantation (ACI) can control the post-traumatic environment and guide graft maturation to support cartilage repair. To investigate both aspects, we examined potential chondro-regenerative effects of lysed platelet concentrate (PC) and supplementary interleukin 10 (IL-10) on mechanically injured cartilage and on clinically used ACI scaffolds. ACI remnants and human cartilage explants, which were applied to an uniaxial unconfined compression as injury model, were treated with human IL-10 and/or PC from thrombocyte concentrates. We analyzed nuclear blebbing/TUNEL, sGAG content, immunohistochemistry, and the expression of COL1A1, COL2A1, COL10A1, SOX9, and ACAN. Post-injuriously, PC was associated with less cell death, increased COL2A1 expression, and decreased COL10A1 expression and, interestingly, the combination with Il-10 or Il-10 alone had no additional effects, except on COL10A1, which was most effectively decreased by the combination of PC and Il-10. The expression of COL2A1 or SOX9 was statistically not modulated by these substances. In contrast, in chondrocytes in ACI grafts the combination of PC and IL-10 had the most pronounced effects on all parameters except ACAN. Thus, using adjuvants such as PC and IL-10, preferably in combination, is a promising strategy for enhancing repair and graft maturation of autologous transplanted chondrocytes after cartilage injury.

Platelet-rich plasma injections induce disease-modifying effects in the treatment of osteoarthritis in animal models

PURPOSE

The mechanisms of action and disease-modifying potential of platelet-rich plasma (PRP) injection for osteoarthritis (OA) treatment are still not fully established. The aim of this systematic review of preclinical evidence was to determine if PRP injections can induce disease-modifying effects in OA joints.

METHODS

A systematic review was performed on animal studies evaluating intra-articular PRP injections as treatment for OA joints. A synthesis of the results was performed investigating the disease-modifying effects of PRP by evaluating studies that compared PRP with OA controls or other injectable products, different PRP formulations or injection intervals, and the combination of PRP with other products. The risk of bias was assessed according to the SYRCLE's tool.

RESULTS

Forty-four articles were included, for a total of 1251 animals. The publication trend remarkably increased over time. PRP injections showed clinical effects in 80% and disease-modifying effects in 68% of the studies, attenuating cartilage damage progression and reducing synovial inflammation, coupled with changes in biomarker levels. Evidence is limited on the best PRP formulation, injection intervals, and synergistic effect with other injectables. The risk of bias was low in 40%, unclear in 56%, and high in 4% of items.

CONCLUSION

Intra-articular PRP injections showed disease-modifying effects in most studies, both at the cartilage and synovial level. These findings in animal OA models can play a crucial role in understanding mechanism of action and structural effects of this biological approach. Nevertheless, the overall low quality of the published studies warrants further preclinical studies to confirm the positive findings, as well as high-level human trials to demonstrate if these results translate into disease-modifying effects when PRP is used in the clinical practice to treat OA.

LEVEL OF EVIDENCE

Level II.

Healing through the lens of immunothrombosis: Biology-inspired, evolution-tailored, and human-engineered biomimetic therapies

Evolution, from invertebrates to mammals, has yielded and shaped immunoclotting as a defense and repair response against trauma and infection. This mosaic of immediate and local wound-sealing and pathogen-killing mechanisms results in survival, restoration of homeostasis, and tissue repair. In mammals, immunoclotting has been complemented with the neuroendocrine system, platelets, and contact system among other embellishments, adding layers of complexity through interconnecting blood-born proteolytic cascades, blood cells, and the neuroendocrine system. In doing so, immunothrombosis endows humans with survival advantages, but entails vulnerabilities in the current unprecedented and increasingly challenging environment. Immunothrombosis and tissue repair appear to go hand in hand with common mechanisms mediating both processes, a fact that is underlined by recent advances that are deciphering the mechanisms of the repair process and of the biochemical pathways that underpins coagulation, hemostasis and thrombosis. This review is intended to frame both the universal aspects of tissue repair and the therapeutic use of autologous fibrin matrix as a biology-as-a-drug approach in the context of the evolutionary changes in coagulation and hemostasis. In addition, we will try to shed some light on the molecular mechanisms underlying the use of the autologous fibrin matrix as a biology-inspired, evolution-tailored, and human-engineered biomimetic therapy.

Intraosseous Injections Are Safe And Effective in Knee Osteoarthritis: A Systematic Review

PURPOSE

To evaluate clinical outcomes after intraosseous injection for knee osteoarthritis systematically with available clinical evidence.

METHODS

A systematic search methodology of the PUBMED, EMBASE, and CINAHL databases was conducted in November 2020. The search workflow was in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The following inclusion criteria were adopted: clinical trials of any level of evidence, reporting clinical outcomes following intraosseous injections of bone substitutes or biologic agents, and mesenchymal stem cells or platelet-rich plasma into the knee as treatment modalities for osteoarthritis. Duplicate data and articles not written in English were excluded from this review.

RESULTS

Six studies were identified and included in this review, with a total of 167 patients. Two studies used subchondroplasty CaP injections, while 4 studies used intraosseous injections of platelet-rich plasma. Two studies provided Level II evidence, 2 studies provided Level III evidence, and a further 2 provided Level IV evidence. Five out of 6 studies reported data using the visual analog scale, 4 studies used the Knee Injury and Osteoarthritis Outcome Score, while 3 studies used the Western Ontario and McMaster Universities Osteoarthritis Index. Clinical improvements in pain and functionality were documented in all trials, with only a few patients experiencing adverse events.

CONCLUSION

Intraosseous injections for knee osteoarthritis are safe and effective. However, multiple pertinent variables such as safety, cost of treatment, and performance against placebos and other treatment modalities require further evaluation before intraosseous injections can be considered as standard treatment for patients presenting with osteoarthritis of the knee.

Intra-Articular Injections of Platelet-Rich Plasma, Adipose Mesenchymal Stem Cells, and Bone Marrow Mesenchymal Stem Cells Associated With Better Outcomes Than Hyaluronic Acid and Saline in Knee Osteoarthritis: A Systematic Review and Network Meta-analysis

PURPOSE

To perform a network meta-analysis to evaluate clinical efficacy and treatment-related adverse events (AEs) of intra-articular hyaluronic acid (HA), leukocyte-poor platelet-rich plasma (LP-PRP), leukocyte-rich platelet-rich plasma (LR-PRP), bone marrow mesenchymal stem cells (BM-MSCs), adipose mesenchymal stem cells (AD-MSCs), and saline (placebo) during 6 and 12 months of follow-up.

METHODS

Six databases were searched for randomized controlled trials. Outcome assessment included the visual analog scale (VAS) score, Western Ontario and McMaster Universities Osteoarthritis (WOMAC) pain subscore, WOMAC score, International Knee Documentation Committee (IKDC) subjective score, and treatment-related AEs. Main inclusion criteria were at least one of the aforementioned outcome measurements, a minimum follow-up period of 5 months, and >80% patient follow-up. Treatments combined with the use of other operations or drugs were excluded.

RESULTS

Forty-three studies meeting the eligibility criteria were included. At 6 months, VAS scores and WOMAC pain subscores showed that AD-MSCs were the best treatment option (surface under the cumulative ranking curve [SUCRA] = 96.7%, SUCRA = 85.3%, respectively). According to WOMAC scores and subjective IKDC scores, LP-PRP was the most effective treatment (SUCRA = 86.0%, SUCRA = 80.5%, respectively). At 12 months, only AD-MSCs were associated with improved VAS scores compared with the placebo (weighted mean difference [WMD] = -20.93, 95% credibility interval [CrI], -41.71 to -0.78). Both LP-PRP and AD-MSCs were more beneficial than the placebo for improving WOMAC pain subscores (WMD = -30.08; 95% CrI, -53.59 to -6.25; WMD = -34.85; 95% CrI, -68.03 to -4.86, respectively). For WOMAC scores, LP-PRP and LR-PRP were significantly associated with improved WOMAC scores compared with the placebo after sensitivity analysis was performed (WMD = -35.26; 95% CrI, -64.99 to -6.01; WMD = -38.69; 95% CrI, -76.21 to -2.76). LP-PRP exhibited relatively better efficacy in improving subjective IKDC scores than the placebo (WMD = 13.67; 95% CrI, 4.05-23.39). Regarding safety, all treatments except for LP-PRP (relative risk = 1.83; 95% CrI, 0.89-4.64) increased treatment-related AEs compared with the placebo.

CONCLUSIONS

Based on the results of current research findings, during 6 months of follow-up, AD-MSCs relieved pain the best; LP-PRP was most effective for functional improvement. During the 12-month follow-up, both AD-MSCs and LP-PRP showed potential clinical pain relief effects; functional improvement was achieved with LP-PRP. Unfortunately, AD-MSC/LP-PRP functional comparisons were only based on WOMAC scores due to missing IKDC scores. BM-MSCs seem to have potentially beneficial effects, but the wide credibility interval makes it impossible to draw a well-supported conclusion. HA viscosupplementation clinical efficacy was lower than that of biological agents during follow-up, which may be related to the properties of the drugs. Considering the evaluation of treatment-related AEs, LP-PRP is the most advisable choice; although the AEs of these treatments are not serious, they may affect treatment compliance and satisfaction.

LEVEL OF EVIDENCE

Level II, meta-analysis of Level I and II studies.

Allogenic Pure Platelet-Rich Plasma Therapy for Adhesive Capsulitis: A Bed-to-Bench Study With Propensity Score Matching Using a Corticosteroid Control Group

BACKGROUND

While platelet-rich plasma (PRP) has been widely studied for musculoskeletal disorders, few studies to date have reported its use for adhesive capsulitis (AC). Fully characterized and standardized allogenic PRP may provide clues to solve the underlying mechanism of PRP with respect to synovial inflammation and thus may clarify its clinical indications.

PURPOSE

To clinically evaluate the safety and efficacy of a fully characterized pure PRP injection in patients with AC and to assess the effects of pure PRP on synoviocytes with or without inflammation in vitro.

STUDY DESIGN

Controlled laboratory study and cohort study; Level of evidence, 3.

METHODS

For the clinical analysis, a total of 15 patients with AC received an ultrasonography-guided intra-articular PRP injection and were observed for 6 months. Pain, range of motion (ROM), muscle strength, shoulder function, and overall satisfaction in the patients were evaluated using questionnaires at 1 week as well as at 1, 3, and 6 months after the PRP injection and results were compared with the results of a propensity score-matched control group that received a corticosteroid injection (40 mg triamcinolone acetonide). For the in vitro analysis, synoviocytes were cultured with or without interleukin-1β (IL-1β) and PRP. The gene expression of proinflammatory and anti-inflammatory cytokines as well as matrix enzymes and their inhibitors was evaluated.

RESULTS

At 6-month follow-up, pure PRP significantly decreased pain and improved ROM, muscle strength, and shoulder function to levels comparable with those after a corticosteroid injection. All pain values, strength measurements, and functional scores significantly improved up to 6 months in the PRP group, but these measures improved up to 3 months and then were decreased at 6 months in the corticosteroid group. ROM was significantly improved in the 2 groups at 6 months compared with baseline. Allogenic PRP did not cause adverse events. For the in vitro findings, PRP induced inflammation but significantly improved the IL 1β-induced synovial inflammatory condition by decreasing proinflammatory cytokines such as IL-1β, tumor necrosis factor-α, IL-6, cyclooxygenase-2, and microsomal prostaglandin E synthase-1 and decreased matrix enzymes (matrix metalloproteinase-1, -3, and -13 as well as a disintegrin and metalloproteinase with thrombospondin motifs-4 and -5) and further increasing anti-inflammatory cytokines such as vasoactive intestinal peptide.

CONCLUSION

This study showed that PRP decreased pain and improved shoulder ROM and function to an extent comparable with that of a corticosteroid in patients with AC. Allogenic pure PRP acted in a pleiotropic manner and decreased proinflammatory cytokines only in the inflammatory condition.

CLINICAL RELEVANCE

Allogenic PRP could be a treatment option for the inflammatory stage of AC.

Adverse Reactions and Clinical Outcomes for Leukocyte-Poor Versus Leukocyte-Rich Platelet-Rich Plasma in Knee Osteoarthritis: A Systematic Review and Meta-analysis

Background:

Platelet-rich plasma (PRP) has gained attention as a therapeutic option for knee osteoarthritis; however, its efficacy varies widely. Leukocytes in PRP raise the concern of aggravating proinflammatory activity. To date, PRP has rarely been investigated with regard to leukocyte concentration.

Purpose:

To provide clinical evidence of the intra-articular injection of PRPs containing different leukocyte concentrations.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

We systematically searched the MEDLINE, Embase, Cochrane Library, CINAHL, and Scopus databases. PRP was classified into leukocyte-poor (LP-PRP) and leukocyte-rich (LR-PRP). Clinical outcomes including Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), visual analog scale (VAS) for pain score, International Knee Documentation Committee (IKDC) subjective score, and adverse reactions were evaluated. The Methodological Index for Non-Randomized Studies criteria were used for quality assessment.

Results:

Included were 32 studies with an evidence level between 1 and 4. Both LP-PRP and LR-PRP showed improvements above the minimal clinically important difference (MCID) in VAS pain score. No significant intergroup difference was seen at 3, 6, or 12 months of follow-up. Regarding function, both LP-PRP and LR-PRP showed improvements above the MCID in the WOMAC and IKDC scores, with no significant difference between the groups. Adverse reactions for pain were significantly higher in LR-PRP than in LP-PRP (odds ratio, 1.64; 95% confidence interval, 1.29-2.10; P = .01). After intra-articular PRP injection, LR-PRP showed a significantly higher rate of swelling than LP-PRP (odds ratio, 1.56; 95% confidence interval, 1.22-1.99; P = .02). The mean Methodological Index for Non-Randomized Studies score of the included studies was 18.6 (range, 10-24).

Conclusion:

Intra-articular PRP injection resulted in improvements above the MCID in terms of pain and function in patients with knee osteoarthritis up to 12 months. The risk of local adverse reactions appeared to be increased after LR-PRP compared with LP-PRP injection. The findings of this review can support the potential use of intra-articular PRP injection for the treatment of knee osteoarthritis. In clinical application, clinicians need to consider selecting a specific type of PRP for knee osteoarthritis.

Intra-articular injections of platelet-rich plasma in symptomatic knee osteoarthritis: a consensus statement from French-speaking experts

PURPOSE

There has been much debate regarding the use of intra-articular injections of platelet-rich plasma (PRP) as symptomatic treatment for knee osteoarthritis. The objective of this consensus was to develop guidelines for PRP injections in knee osteoarthritis according to the French National Authority for Health recommendations.

METHODS

Fifteen physicians from different French-speaking countries (10 rheumatologists, 4 specialists in rehabilitation and sports medicine and 1 radiologist) were selected for their expertise in the areas of PRP and osteoarthritis. A comprehensive literature review was conducted on Medline including all published therapeutic trials, open studies, meta-analysis and systematic reviews focusing on the effects of PRP in knee OA, as well as fundamental studies concerning the characteristics of the various types of PRP and their mechanisms, indexed before April 2019. Using the method recommended by the French National Authority for Health inspired by the Delphi consensus process, 25 recommendations were finally retained and evaluated. The recommendations were classified as appropriate or not appropriate, with strong or relative agreement, or uncertain if a consensus was not achieved.

RESULTS

Among the 25 recommendations selected, the main ones are the following: (1) Intra-articular injections of PRP are an effective symptomatic treatment for early to moderate knee osteoarthritis. This recommendation was considered appropriate with a relative agreement (Median = 8; rank = 6-9). Level of evidence 1A. (2) A PRP treatment sequence in knee osteoarthritis may include 1-3 injections. This recommendation was considered appropriate with a strong agreement (Median = 9; rank = 7-9). Level of evidence 1A. (3) Leucocytes-poor PRP should be preferred in knee osteoarthritis. This recommendation was considered appropriate with a relative agreement (Median = 8; rank = 5-9). Level of evidence 5. (4) Intra-articular PRP knee injections should be performed under ultrasound or fluoroscopic guidance. This recommendation was considered uncertain with no consensus (Median = 8; rank = 3-9). Level of evidence 5. (5) PRP should not be mixed with an anesthetic or intra-articular corticosteroid. This recommendation was considered appropriate with a relative agreement (Median = 9; rank = 6-9). Level of evidence 5 CONCLUSION: Those 25 recommendations should standardize and facilitate the use of IA PRP injections, which are considered by experts as an effective treatment especially in early or moderate knee OA. Although a strong or relative agreement from the experts was obtained for most of the recommendations, many of them had a very low level of evidence (Level 5) and were principally based on the clinical experience of the experts.

PRP in wound healing applications

Platelets play a crucial role in hemostasis, tissue regeneration and host defense. Based on these settings, platelet-rich plasma (PRP) and its derivatives are therapeutically used to promote wound healing in several scenarios. This review summarizes the biological mechanisms underlying the most traditional as well as innovative applications of PRP in wound healing. These mechanisms involve the combined action of platelet-derived growth factors and cytokines, together with the role of plasma-derived fibrillar, antioxidant and homeostatic factors. In addition, regenerative treatments with PRP consist of personalized and non-standardized methods. Thus, the quality of PRP varies depending on endogenous factors (e.g., age; gender; concomitant medication; disease-associated systemic factors; nutrition) and exogenous factors (anticoagulants and cellular composition). This review also analyses whether these factors affect the biological mechanisms of PRP in wound healing applications.

Complement Expression and Activation in Osteoarthritis Joint Compartments

Objective

To investigate complement(C) factors(F) and their activation fragments expression in OA joint tissues.

Design

Immunohistochemistry and quantitative imaging were performed to analyze C3, C4, and CF (factor) B expression on osteochondral biopsies (43 patients) collected during arthroplasty. Isolated chondrocytes and synoviocytes, cartilage and synovial tissues obtained from surgical specimens of OA patients (15 patients) were cultured with or without IL-1β. Real time PCR for CFB, C3, and C4 was performed. Culture supernatants were analyzed for C3a, C5a, CFBa, and terminal complement complex (TCC) production.

Results

In osteochondral biopsies, C factor expression was located in bone marrow, in a few subchondral bone cells and chondrocytes. C3 was the most expressed while factor C4 was the least expressed factor. Gene expression showed that all C factors analyzed were expressed both in chondrocytes and synoviocytes. In chondrocyte cultures and cartilage explants, CFB expression was significantly higher than C3 and C4. Furthermore, CFB, but not C3 and C4 expression was significantly induced by IL-1β. As to C activation factors, C3a was the most produced and CFBa was induced by IL-1β in synovial tissue. TCC production was undetectable in isolated chondrocytes and synoviocytes cell culture supernatants, whereas it was significantly augmented in cartilage explants.

Conclusion

C factors were locally produced and activated in OA joint with the contribution of all tissues (cartilage, bone, and synovium). Our results support the involvement of innate immunity in OA and suggest an association between some C alternative pathway component and joint inflammation.

Biological strategies for osteoarthritis: from early diagnosis to treatment

PURPOSE

To provide an updated review of the literature on the use of orthobiologics as a potential treatment option to alleviate symptoms associated with osteoarthritis (OA), slow the progression of the disease, and aid in cartilage regeneration.

METHODS

A comprehensive review of the literature was performed to identify basic science and clinical studies examining the role of orthobiologics in the diagnosis and management of osteoarthritis.

RESULTS

Certain molecules (such as interleukin-6 (IL-6), interleukin-8 (IL-8), matrix metalloproteinase (MMPs), cartilage oligomeric matrix protein (COMP), and tumor necrosis factor (TNF), microRNAs, growth differentiation factor 11 (GDF-11)) have been recognized as biomarkers that are implicated in the pathogenesis and progression of degenerative joint disease (DJD). These biomarkers have been used to develop newer diagnostic applications and targeted biologic therapies for DJD. Local injection therapy with biologic agents such as platelet-rich plasma or stem cell-based preparations has been associated with significant improvement in joint pain and function in patients with OA and has increased in popularity during the last decade. The combination of PRP with kartogenin or TGF-b3 may also enhance its biologic effect. The mesenchymal stem cell secretome has been recognized as a potential target for the development of OA therapies due to its role in mediating the chondroprotective effects of these cells. Recent experiments have also suggested the modification of gut microbiome as a newer method to prevent OA or alter the progression of the disease.

CONCLUSIONS

The application of orthobiologics for the diagnosis and treatment of DJD is a rapidly evolving field that will continue to expand. The identification of OA-specific and joint-specific biomarker molecules for early diagnosis of OA would be extremely useful for the development of preventive and therapeutic protocols. Local injection therapies with HA, PRP, BMAC, and other stem cell-based preparations are currently being used to improve pain and function in patients with early OA or those with progressed disease who are not surgical candidates. Although the clinical outcomes of these therapies seem to be promising in clinical studies, future research will determine the true role of orthobiologic applications in the field of DJS.

Efficacy of Autologous Conditioned Serum (ACS), Platelet-Rich Plasma (PRP), Hyaluronic Acid (HA) and Steroid for Early Osteoarthritis Knee: A Comparative Analysis

BACKGROUND

Intra-articular injection therapy constituting corticosteroids, viscosupplements and blood-derived products are considered to have a key role in non-operative management of osteoarthritis knee. While corticosteroids and viscosupplements have proven short-term efficacy in early osteoarthritis; orthobiologics are gaining increased attention in osteoarthritis management. The aim of present study was thus to compare two commonly used biologics (platelet-rich plasma/PRP and autologous conditioned serum/ACS) to each other and to established therapies.

METHODS

After required institutional clearances, all patients presenting with early primary osteoarthritis knee who had failed initial conservative management and received only unilateral knee injection were included. Patients in the PRP group were compared to the other groups (comprising the HA/hyaluronic acid group, steroid group, and a matched cohort who had been administered ACS for the same indication earlier). Clinical outcome was evaluated using the Western Ontario and McMaster Universities Arthritis Index (WOMAC) questionnaire and Visual Analogue scale (VAS) pre-injection and at 6 months.

RESULTS

ACS and PRP did not have any significant difference in terms of either WOMAC score (p = 0.154) or VAS score at 6 months (p = 0.850). The scores for both these orthobiologics were better than the control groups (HA group and Steroid group). Between the two control groups, HA group had better VAS scores as compared to the Steroid group (p = 0.008).

CONCLUSION

The clinical outcomes following intra-articular injection of ACS and PRP are better than controls (HA and steroid), but a difference between the two orthobiologics could not be demonstrated.

LEVEL OF EVIDENCE

3b.

Autologous Protein Solution Injections for the Treatment of Knee Osteoarthritis: 3-Year Results

BACKGROUND

Blood derivative injections have been recently proposed to address osteoarthritis (OA) with overall positive results, although long-term data on their efficacy are lacking. A novel blood derivative has been developed to concentrate growth factors and antagonists of inflammatory cytokines and shown promising early findings.

PURPOSE

To investigate if the positive effects of a single intra-articular injection of autologous protein solution (APS) in patients affected by knee OA-previously documented at 1 year in a multicenter double-blind randomized saline-controlled trial-last up to 3 years.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 46 patients with Kellgren-Lawrence 2 or 3 knee OA were randomized into 2 groups: 1 ultrasound-guided APS injection (n = 31) or 1 saline injection (n = 15). At 1 year, the saline group was allowed to cross over. Patients were re-evaluated at 24 and 36 months through the visual analog scale for pain (VAS), Western Ontario and McMaster Universities Osteoarthritis Index Likert 3.1 (WOMAC LK 3.1), Knee injury and Osteoarthritis Outcome Score (KOOS), 36-Item Short Form Health Survey (SF-36), and Outcome Measures in Rheumatology-Osteoarthritis Research Society International (OMERACT-OARSI) responder rate. Magnetic resonance imaging evaluation was performed with the MRI Osteoarthritis Knee Score (MOAKS) before and at 24 months after treatment, and radiographs were assessed per Kellgren-Lawrence before and annually after treatment.

RESULTS

In the APS cohort, WOMAC pain improved from 11.5 ± 2.4 (mean ± SD) to 4.3 ± 4.0 at 1 year and to 5.7 ± 5.0 at 3 years (P < .0001 vs baseline). The APS cohort also showed a statistically significant improvement in its KOOS pain score from 39.4 ± 13.1 to 70.6 ± 21.5 at 1 year and to 64.1 ± 24.6 at 3 years (P < .0001 vs baseline) and VAS pain scores from 5.5 ± 2.2 to 2.6 ± 2.5 at 1 year and to 3.4 ± 2.9 at 3 years (P = .0184 vs baseline). VAS pain score significantly worsened from 12 to 36 months (P = .0411). All patients in the saline group decided to cross over to APS, and their final scores were better than baseline, although not significantly better than at the crossover point. Overall, 7 of 26 (26.9%) APS cases and 4 of 14 (28.6%) crossover cases were considered failures as patients underwent further injective treatments or surgical procedures between the 12- and 36-month follow-up. MOAKS findings showed no statistically significant differences. Patients with better cartilage had greater WOMAC pain improvement when their baseline scores were worse, whereas the trend was reversed for patients with cartilage loss at baseline.

CONCLUSION

Intra-articular use of APS for mild to moderate knee OA was safe, and significant pain improvement was documented 3 years after a single injection. Patients with better cartilage status seem to respond better than patients with more cartilage loss, with more clinical improvement even when starting from more painful conditions.

REGISTRATION

NCT02138890 (ClinicalTrials.gov identifier).

The efficiency of platelet-rich plasma treatment in patients with knee osteoarthritis

OBJECTIVE

The aim of this study was to determine the effects of platelet-rich plasma (PRP) treatment on pain, functionality, quality of life, and cartilage thickness in patients with knee osteoarthritis (OA).

METHODS

Sixty patients with chronic knee pain were randomly separated into two groups. The first group was administered 4-ml PRP intra-articularly (IA) in three doses at one-week intervals, and the second group had only one dose of a 4-ml saline solution IA. The patients' pain was measured using the Visual Analogue Scale (VAS); functionality was measured using the Western Ontario and McMaster University Osteoarthritis Index (WOMAC). The distal femur cartilage thickness was assessed using ultrasonography (USG).

RESULTS

All baseline parameters were similar (p> 0.05). In the first and sixth months after the treatment, the VAS scores of the PRP group were significantly low (p< 0.001). In the same group, only the pain sub-score was low in the WOMAC assessment in the first month after treatment. However, in the sixth month, all parameters of the WOMAC score were lower than those of the placebo group (p< 0.05). Cartilage thickness measurements were similar in the two groups (p< 0.05).

CONCLUSION

PRP treatment had positive effects on the pain, physical function, and quality of life of patients with knee OA, but it did not increase cartilage thickness.

Evidence on ankle injections for osteochondral lesions and osteoarthritis: a systematic review and meta-analysis

PURPOSE

To evaluate the evidence supporting safety and effectiveness of intra-articular injective treatments for ankle lesions ranging from osteochondral lesions of the talus (OLT) to osteoarthritis (OA).

METHODS

A systematic review and a meta-analysis were performed on PubMed, Embase, and Cochrane Library in March 2020. Safety was evaluated through the reported side effects and effectiveness through the scores used. The quality of the studies was assessed using the Cochrane Collaboration Risk of Bias 2.0 tool and the Downs and Black checklist. For each outcome, the quality of evidence was graded according to GRADE guidelines.

RESULTS

Twenty-four studies (21 for OA, 3 for OLT) were included on hyaluronic acid (HA), platelet-rich plasma (PRP), saline, methylprednisolone, botulinum toxin type A (BoNT-A), mesenchymal stem cells (MSCs), and prolotherapy. No severe adverse events were reported. For OLT, a comparison was possible between HA and PRP showing no significant difference. For ankle OA, a significant difference favouring HA versus saline was documented at six months (p < 0.001). The GRADE level of evidence was very low.

CONCLUSION

This meta-analysis supports the safety of intra-articular treatment for ankle OA and OLT, while only a very low evidence supports the efficacy of HA in terms of better results versus placebo for the treatment of ankle OA, and other conclusions are hindered by the scarcity of the available literature. This urges further and stronger trials to specifically investigate potential and limitations of these different injective approaches for the treatment of OLT and ankle OA.

Intra-articular Injection of Pure Platelet-Rich Plasma Is the Most Effective Treatment for Joint Pain by Modulating Synovial Inflammation and Calcitonin Gene-Related Peptide Expression in a Rat Arthritis Model

BACKGROUND

Platelet-rich plasma (PRP) has emerged as a treatment for osteoarthritis (OA). However, the effect that leukocyte concentrations in PRP have on OA remains unclear.

PURPOSE

To clarify the optimal PRP formulation for OA treatment by comparing pure PRP, leukocyte-poor PRP (LP-PRP), and leukocyte-rich PRP (LR-PRP) in a rat arthritis model.

STUDY DESIGN

Controlled laboratory study.

METHODS

Knee arthritis was induced bilaterally in male Wistar rats with intra-articular injections of monosodium iodoacetate (MIA) on day 0. Rats were randomly assigned to 1 of 3 treatment groups (pure PRP, LP-PRP, and LR-PRP). On day 1, allogenic PRP was injected into the right knee of rats and phosphate-buffered saline was injected into the left knee as a control. Weight distribution on the hindlimbs was measured for 14 days to assess pain behavior. Rats were euthanized at day 5 or 14 for histological assessment of synovial tissue and cartilage. Immunohistochemical staining of calcitonin gene-related peptide (CGRP) and α-smooth muscle actin was performed to determine the mechanism of pain relief induced by the PRP preparations.

RESULTS

In all groups, PRP increased the load-sharing ratio on PRP-injected knees, with pure PRP eliciting the largest effect among the 3 kinds of PRP (P < .05). Structural changes in the synovial tissue were significantly inhibited in the pure-PRP group compared with the control group after both 5 and 14 days (P < .001 and P = .025, respectively), whereas no significant difference was found between the control, LP-PRP, and LR-PRP groups. An inhibitory effect on cartilage degeneration was observed only in the pure-PRP group on day 14. Pure PRP also significantly inhibited expression of CGRP-positive nerve fibers in the infrapatellar fat pad compared with the other groups (P < .05).

CONCLUSION

In an MIA-induced arthritis model, pure PRP injection was the most effective treatment for reduction of pain-related behavior and inhibition of synovial inflammation and pain sensitization.

CLINICAL RELEVANCE

PRP formulations should be optimized for each specific disease. This study shows the superiority of pure PRP for treatment of arthritis and joint pain.

Growth Factor Delivery to a Cartilage-Cartilage Interface Using Platelet-Rich Concentrates on a Hyaluronic Acid Scaffold

PURPOSE

To determine whether (1) human leukocyte-platelet-rich plasma (L-PRP) or (2) leukocyte-platelet-rich fibrin (L-PRF) delivered on a hyaluronic acid (HA) scaffold at a bovine chondral defect, a simulated cartilage tear interface, in vitro would improve tissue formation based on biomechanical, histologic, and biochemical measures.

METHODS

L-PRF and L-PRP were prepared from 3 healthy volunteer donors and delivered in conjunction with HA scaffolds to defects created in full-thickness bovine cartilage plugs harvested from bovine femoral condyle and trochlea. Specimens were cultured in vitro for up to 42 days. Treatment groups included an HA scaffold alone and scaffolds containing L-PRF or L-PRP. Cartilage repair was assessed using biomechanical testing, histology, DNA quantification, and measurement of sulfated glycosaminoglycan and collagen content at 28 and 42 days.

RESULTS

L-PRF elicited the greatest degree of defect filling and improvement in other histologic measures. L-PRF-treated specimens also had the greatest cellularity when compared with L-PRP and control at day 28 (560.4 μg vs 191.4 μg vs 124.2 μg, P = .15); at day 48, there remained a difference, although not significant, between L-PRF versus L-PRP (761.1 μg vs 589.3 μg, P = .219) . L-PRF had greater collagen deposition when compared with L-PRP at day 42 (40.1 μg vs 16.3 μg, P < .0001). L-PRF had significantly greater maximum interfacial strength compared with the control at day 42 (10.92 N vs 0.66 N, P = .015) but had no significant difference compared with L-PRP (10.92 N vs 6.58 N, P = .536). L-PRP facilitated a greater amount of sulfated glycosaminoglycan production at day 42 when compared with L-PRF (15.9 μg vs 4.3 μg, P = .009).

CONCLUSIONS

Delivery of leukocyte-rich platelet concentrates in conjunction with a HA scaffold may allow for improvements in cartilage healing through different pathways. L-PRF was not superior to L-PRP in its biomechanical strength, suggesting that both treatments may be effective in improving biomechanical strength of healing cartilage through different pathways.

CLINICAL RELEVANCE

The delivery of platelet-rich concentrates in conjunction HA scaffolds may augment healing cartilaginous injuries.

Release kinetic of pro- and anti-inflammatory biomolecules from platelet-rich plasma and functional study on osteoarthritis synovial fibroblasts

BACKGROUND AIMS

This study evaluated the release kinetics of numerous representative and less studied platelet-rich plasma (PRP) cytokines/chemokines with regard to the effects of various cellular compositions and incubation times. In addition, the biological effects of different PRPs on osteoarthritis synovial fibroblasts in vitro were tested.

METHODS

Peripheral whole blood was collected from healthy donors, and pure platelet-rich plasma (P-PRP), leukocyte-rich platelet-rich plasma (L-PRP) and platelet-poor plasma (PPP) were prepared for the analysis of the following biomolecules: IL-1β, IL-4, IL-6, IL-10, IL-17a, IL-22, MIP-1α/CCL-3, RANTES/CCL-5, MCP-3/CCL-7, Gro-α/CXCL-1, PF-4/CXCL-4, ENA-78/CXCL-5, NAP-2/CXCL-7, IL-8/CXCL-8, Fractalkine/CX3CL-1, s-CD40L P-PRP, L-PRP and PPP. Their effect on osteoarthritis synovial fibroblasts in vitro was tested by analyzing changes induced in both gene expression on a panel of representative molecules involved in physiopathology of joint environment and synthesis of IL-1β, IL-8 and hyaluronic acid.

RESULTS

This study demonstrated that among the 16 analyzed biomolecules, four were undetectable, whereas most of the detected biomolecules were more concentrated in L-PRP even when concentrations were normalized to platelet number. Despite the pro-inflammatory boost, the various PRP preparations did not alter synovial fibroblast gene expression of specific factors that play a pivotal role in joint tissue homeostasis and are able to induce anti-inflammatory (TIMP-1) biomolecules.

DISCUSSION

This study provides a set of reference data on the concentration and release kinetics of some less explored biomolecules that could represent potential specific effectors in the modulation of inflammatory processes and in tissue repair after treatment with PRP.

Platelet-Rich Plasma Augmentation to Microfracture Provides a Limited Benefit for the Treatment of Cartilage Lesions: A Meta-analysis

Background:

Microfracture is the most common first-line option for the treatment of small chondral lesions, although increasing evidence shows that the clinical benefit of microfracture decreases over time. Platelet-rich plasma (PRP) has been suggested as an effective biological augmentation to improve clinical outcomes after microfracture.

Purpose:

To evaluate the clinical evidence regarding the application of PRP, documenting safety and efficacy of this augmentation technique to improve microfracture for the treatment of cartilage lesions.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

A systematic review was performed in PubMed, EBSCOhost database, and the Cochrane Library to identify comparative studies evaluating the clinical efficacy of PRP augmentation to microfracture. A meta-analysis was performed on articles that reported results for visual analog scale (VAS) for pain, International Knee Documentation Committee (IKDC), and American Orthopaedic Foot and Ankle Society (AOFAS) scores. Risk of bias was documented through use of the Cochrane Collaboration Risk of Bias 2.0 and Risk of Bias in Non-randomized Studies of Interventions assessment tools. The quality assessment was performed according to the Grading of Recommendations Assessment, Development and Evaluation guidelines.

Results:

A total of 7 studies met the inclusion criteria and were included in the meta-analysis: 4 randomized controlled trials, 2 prospective comparative studies, and 1 retrospective comparative study, for a total of 234 patients. Of the 7 studies included, 4 studies evaluated the effects of PRP treatment in the knee, and 3 studies evaluated effects in the ankle. The analysis of all scores showed a difference favoring PRP treatment in knees (VAS, P = .002 and P < .001 at 12 and 24 months, respectively; IKDC, P < .001 at both follow-up points) and ankles (both VAS and AOFAS, P < .001 at 12 months). The improvement offered by PRP did not reach the minimal clinically important difference (MCID).

Conclusion:

PRP provided an improvement to microfracture in knees and ankles at short-term follow-up. However, this improvement did not reach the MCID, and thus it was not clinically perceivable by the patients. Moreover, the overall low evidence and the paucity of high-level studies indicate further research is needed to confirm the potential of PRP augmentation to microfracture for the treatment of cartilage lesions.