The Effect of Leukocyte Concentration on Platelet-Rich Plasma Injections for Knee Osteoarthritis: A Network Meta-Analysis

Platelet-Rich Plasma for Knee and Hip Osteoarthritis Pain: A Scoping Review

PURPOSE OF REVIEW

Platelet-rich plasma (PRP) is an emerging biological intervention for osteoarthritis (OA), yet the outcomes remain uncertain. The purpose of this study was to review current literature regarding the use of PRP for knee and hip OA.

RECENT FINDINGS

Recent systematic reviews have found significant clinical improvements in outcomes after the administration of PRP compared to hyaluronic acid (HA) in patients with knee OA. One of these reviews included bone marrow aspirate concentrate (BMAC) as a comparison group and found no significant differences in outcomes between PRP and BMAC. Currently, the literature is lacking on whether leukocyte-rich or leukocyte-poor PRP is superior in patients with knee OA. The literature on PRP for hip OA has not provided consistent results as it has for the knee. Two recent systematic reviews evaluated RCTs for patients undergoing treatment with either PRP or HA for hip OA and found no significant differences in clinical outcomes between groups at final follow-up. Current literature regarding the association between OA grade and PRP efficacy has found varying results. The use of PRP injections in the treatment of knee OA appears to be favorable, resulting in clinically comparable or superior outcomes compared to other injection treatments. However, the clinical efficacy of PRP injections in hip OA is far less consistent. Evidence is lacking to suggest that the presence of leukocytes significantly influences clinical outcomes. Further randomized controlled trials on larger cohorts, with longer follow-up, and with comparable formulations are required before recommendations can be made regarding use of PRP for hip OA, the effect of leukocyte concentration, and clinical efficacy based on OA grade.

Ultrasound-Guided Subfascial Platelet-Rich Plasma Injections Versus Enthesis Needling for Greater Trochanteric Pain Syndrome: A Randomized Controlled Trial

Background

Greater trochanteric pain syndrome (GTPS) is characterized by gluteal enthesopathy involving the peritrochanteric space and associated with chronic pain and functional impairment. A corticosteroid injection in the trochanteric bursa is the usual palliative treatment for pain. However, it is important to investigate treatment options that will relieve pain in the peritrochanteric space.

Purpose

To compare the clinical efficacy of subfascial platelet-rich plasma (PRP) injection and enthesis needling for GTPS.

Study Design

Randomized controlled trial; Level of evidence, 1.

Methods

A total of 92 patients (90% women; mean age, 55 years old; mean body mass index, 25.3 kg/m2) were randomly divided into a subfascial PRP injection group and an enthesis needling group. Descriptive data and radiographic measurements of the pelvis-including leg-length difference, pelvic width difference, and pelvic trochanteric index-were recorded. The primary outcome measures were the Hip Outcome Score (HOS) activities of daily living (HOS-ADL) and sports-specific (HOS-SS) subscales and the visual analog scale for pain at 3, 6, and 12 months posttreatment. In addition, we evaluated the presence or absence of ultrasound characteristics (fascia nodules, trochanteric bursa distension, and calcium deposits) over time in response to treatment.

Results

Baseline demographic and radiological characteristics were similar between the groups. The PRP group saw significantly greater improvement from baseline to 12 months posttreatment on the HOS-SS subscore compared with the needling group (32.09 [95% CI, 28.99-40.20] vs 20.52 [95% CI, 11.99-29.05]; P = .048). At 3 months, 60% of patients in the PRP group versus 33.3% in the needling group had a reduction in pain compared with a baseline of >20% (P = .040). After subfascial PRP injection, fewer patients had a fascia nodule over the trochanter and/or bursa distension (P = .006 and P = .004, respectively). The pelvic trochanteric index was predictive of HOS-ADL and HOS-SS outcomes (P = .011 and P = .022, respectively). The interaction between treatment modality and fascia nodule influenced HOS-ADL and HOS-SS outcomes (P = .021 and P = .023) as well as the interactions of treatment modality, fascia nodules, and calcifications (P = .027).

Conclusion

Both subfascial PRP injection and enthesis needling resulted in clinical improvements, but the improvement in the HOS-SS was greater in the PRP group.

Registration

NCT04231357 (ClinicalTrials.gov identifier).

Platelet-Rich Plasma, Bone Marrow Aspirate Concentrate, and Hyaluronic Acid Injections Outperform Corticosteroids in Pain and Function Scores at a Minimum of 6 Months as Intra-Articular Injections for Knee Osteoarthritis: A Systematic Review and Network Meta-analysis

PURPOSE

To compare the efficacy of common intra-articular injections used in the treatment of knee osteoarthritis, including corticosteroid (CS), hyaluronic acid (HA), platelet-rich plasma (PRP), and bone marrow aspirate concentrate (BMAC), with a minimum follow-up of 6-months.

METHODS

A literature search was conducted using the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines in August 2022 in the following databases: PubMed/MEDLINE, Scopus, Cochrane Database of Controlled Trials, and the Cochrane Database of Systematic Reviews. Level I to II randomized clinical trials with a minimum follow-up of 6 months that investigated the treatments of interest were included. Patient-reported outcome scores for pain and function at baseline and at latest follow-up were extracted, and the change in scores was converted to uniform 0 to 100 scales. Arm-based Bayesian network meta-analysis using a random-effects model was created to compare the treatment arms in pain and function.

RESULTS

Forty-eight studies comprising a total of 9,338 knees were included. The most studied intra-articular injection was HA (40.9%), followed by placebo (26.2%), PRP (21.5%), CS (8.8%), and then BMAC (2.5%). HA and PRP both led to a significant improvement in pain compared with placebo. HA, PRP, and BMAC all led to a significant improvement in function scores when compared with placebo. Surface under the cumulative ranking curves (SUCRAs) of the interventions revealed that PRP, BMAC, and HA were the treatments with the highest likelihood of improvement in both pain and function, with overall SUCRA scores of 91.54, 76.46, and 53.12, respectively. The overall SUCRA scores for CS and placebo were 15.18 and 13.70, respectively.

CONCLUSIONS

At a minimum 6-month follow-up, PRP demonstrated significantly improved pain and function for patients with knee osteoarthritis compared with placebo. Additionally, PRP exhibited the highest SUCRA values for these outcomes when compared with BMAC, HA, and CS.

LEVEL OF EVIDENCE

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

Review of Dohan Eherenfest et al. (2009) on "Classification of platelet concentrates: From pure platelet-rich plasma (P-PRP) to leucocyte- and platelet-rich fibrin (L-PRF)"

This classic discusses the original publication of Dohan Eherenfest et al. on "Classification of platelet concentrates: from pure platelet-rich plasma (P-PRP) to leucocyte- and platelet-rich fibrin (L-PRF)", in which the authors propose four categories of platelet concentrates depending on their leucocyte and fibrin content (P-PRP, leucocyte- and platelet-rich plasma (L-PRP), pure platelet-rich fibrin (P-PRF), and L-PRF) to group a "jungle" of products in which the term platelet-rich plasma (PRP) was used indistinctly. They were able to identify common factors such as: (1) the use of anticoagulants and immediate centrifugation of the blood after its collection; (2) most preparation techniques allowed platelet concentrate preparation within an hour; (3) the centrifugation aimed to separate the blood in layers that would allow the extraction of specific fractions; and (4) the product was activated with thrombin or calcium chloride. The reviewed manuscript has been listed among the most cited PRP articles in regenerative medicine, with more than 800 citations, driving current scientific research and clinical practise by categorising L-PRP and P-PRP (now, leucocyte-poor PRP). The classification has also opened the door to understanding intrinsic biological mechanisms between platelets, leukocytes, fibrin, and growth factors, which will later be considered for studying the proliferation and differentiation of cells in different tissues affected by PRP. Since the initial classification of platelet concentrates, several other classification systems have been proposed and published in the current literature such as platelet, activation, white blood cell (PAW), Mishra, platelet, leucocyte, red blood cells, and activation (PLRA), dose of platelet, efficiency, purity, and activation (DEPA), method, activation, red blood cells, spin, platelets, image guidance, leukocytes, and light activation (MARSPILL), etc. These classifications have identified important aspects of PRP that affect the biological composition and, ultimately, the indications and outcomes. To date, there is still a lack of standardisation in sample preparation, cohort heterogeneity, and incomplete reporting of sample preparation utilised, leading to a lack of clarity and challenging researchers and clinicians.

Postinjection protocols following platelet-rich plasma administration for knee osteoarthritis: A systematic review

OBJECTIVE

Platelet-rich plasma (PRP) use in treating orthopedic conditions has increased, yet evidence of its clinical efficacy is inconsistent and limited by heterogeneity in osteoarthritis (OA) severity, PRP preparations and protocols, and clinical outcome measurement. This review aims to characterize the variations in postinjection protocols in studies assessing the clinical efficacy of PRP for knee OA.

LITERATURE SURVEY

A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A literature search from database inception to February 2023 of CINAHL, MEDLINE, and EMBASE was conducted.

METHODOLOGY

Article screening, data extraction, and risk of bias assessments were completed in duplicate by two reviewers. Primary outcomes were presence/absence and timing of the following postinjection protocol components: nonsteroidal anti-inflammatory drug (NSAID) restrictions, non-NSAID analgesic and cryotherapy use, immediate knee flexion/extension, immediate rest, activity restriction, return-to-activity guidelines, and rehabilitation protocols. A descriptive analysis was used to analyze the data. Given study heterogeneity, a meta-analysis was not performed.

SYNTHESIS

A total of 187 studies were included for analysis. Half of all studies (51.9%) excluded patients due to preinjection NSAID use, most often within 5 days of blood sampling or injection. Postinjection NSAID restriction was included in 42.8% of studies, ranging from 1 to 1800 days. Few studies (19.4%) that permitted non-NSAID analgesia restricted their use prior to clinical assessments. Postinjection immediate flexion, extension, and immobilization were rarely (8.6%) mentioned. Activity restriction was included in a third of studies (35.3%), with the most frequent length of restriction being 1 day. Postinjection return-to-activity protocols were less common (20.3%), usually with a "gradual" and/or "as tolerated" recommendation. A minority of studies (16.0%) reported physical therapy protocols and the vast majority (93.3%) were home based.

CONCLUSION

Significant heterogeneity remains in post-PRP injection protocols, with unclear consensus regarding optimal recommendations and limited rationale for the protocols outlined. Further study is necessary to compare protocols directly and to determine which pre- and postinjection recommendations can result in optimal outcomes.

A Greater Platelet Dose May Yield Better Clinical Outcomes for Platelet-Rich Plasma in the Treatment of Knee Osteoarthritis: A Systematic Review

PURPOSE

To determine whether the platelet dose administered during a platelet-rich plasma (PRP) injection for knee osteoarthritis (OA) affects clinical outcomes.

METHODS

A systematic review was performed by searching PubMed, Cochrane Library, and Embase for randomized controlled trials with at least 1 study arm using PRP for knee OA. Only studies that provided a platelet count, concentration, or dose with a minimum of 6-month outcome scores were included. Studies in which the PRP group had statistically significant positive outcomes were separated from those without statistical significance. The average platelet doses for studies with positive outcomes in the PRP group were compared with those without positive outcomes.

RESULTS

After exclusion criteria were applied, 29 studies were analyzed. Of the 29, there were 31 arms that used PRP as a treatment method, of which 28 had statistically significant positive outcomes at 6 months compared with the control group. The mean platelet dose in the 28 with a positive outcome was 5,500 ± 474 × 106, whereas the 3 that had no positive difference had a mean platelet dose of 2,302 ± 437 × 106 (P < .01). There were 18 studies with 12-month outcomes, with 16 of 18 having positive outcomes. The positive studies had an average platelet dose of 5,464 ± 511, whereas the studies that had no statistical difference had an average platelet dose of 2,253 ± 753 × 106 (P < .05).

CONCLUSIONS

Improved clinical outcomes from PRP injections for knee OA may be related to a greater platelet dose.

LEVEL OF EVIDENCE

Level II, systematic review of Level I and II studies.

Experts Achieve Consensus on a Majority of Statements Regarding Platelet-Rich Plasma Treatments for Treatment of Musculoskeletal Pathology

PURPOSE

To establish consensus statements on platelet-rich plasma (PRP) for the treatment of musculoskeletal pathologies.

METHODS

A consensus process on the treatment of PRP using a modified Delphi technique was conducted. Thirty-five orthopaedic surgeons and sports medicine physicians participated in these consensus statements on PRP. The participants were composed of representatives of the Biologic Association, representing 9 international orthopaedic and musculoskeletal professional societies invited due to their active interest in the study of orthobiologics. Consensus was defined as achieving 80% to 89% agreement, strong consensus was defined as 90% to 99% agreement, and unanimous consensus was indicated by 100% agreement with a proposed statement.

RESULTS

There was consensus on 62% of statements about PRP.

CONCLUSIONS

(1) PRP should be classified based on platelet count, leukocyte count, red blood count, activation method, and pure-plasma versus fibrin matrix; (2) PRP characteristics for reporting in research studies are platelet count, leukocyte count, neutrophil count, red blood cell count, total volume, the volume of injection, delivery method, and the number of injections; (3) the prognostic factors for those undergoing PRP injections are age, body mass index, severity/grade of pathology, chronicity of pathology, prior injections and response, primary diagnosis (primary vs postsurgery vs post-trauma vs psoriatic), comorbidities, and smoking; (4) regarding age and body mass index, there is no minimum or maximum, but clinical judgment should be used at extremes of either; (5) the ideal dose of PRP is undetermined; and (6) the minimal volume required is unclear and may depend on the pathology.

LEVEL OF EVIDENCE

Level V, expert opinion.

Systematic Review of Platelet-Rich Plasma for Low Back Pain

BACKGROUND

Low back pain (LBP) has a high economic burden and is strongly related to the degenerative process of the spine, especially in the intervertebral disc and of the facet joints. Numerous treatment modalities have been proposed for the management of LBP, and the use of platelet-rich plasma (PRP) has emerged as an innovative therapeutic option for degenerative disease of the spine. The present study aims to evaluate the efficacy of PRP injections in managing low back pain.

METHODS

We conducted a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations, a registered at PROSPERO Systematic Reviews Platform, under number CRD42021268491. The PubMed, Web of Science, and Scopus databases were searched to identify relevant articles, along with hand searching to identify gray literature articles, with no language restrictions. Randomized clinical trials (RCTs), nonrandomized trials (NRTs), and case series (CSs) with more than 10 patients were considered eligible. The quality assessment and the risk of bias of the randomized clinical trials were evaluated using the RoB II tool. An evaluation of the description of the preparation methods was performed using an adapted version of the MIBO checklist.

RESULTS

An electronic database search resulted in 2324 articles, and after the exclusion of noneligible articles, 13 RCTs and 27 NRTs or CSs were analyzed. Of the 13 RCTs, 11 found favorable results in comparison to the control group in pain and disability, one showed no superiority to the control group, and one was discontinued because of the lack of therapeutic effect at eight-week evaluation. Description of the PRP preparation techniques were found in almost all papers. The overall risk of bias was considered high in 2 papers and low in 11. An adapted MIBO checklist showed a 72.7% compliance rate in the selected areas.

CONCLUSIONS

In this systematic review, we analyzed articles from English, Spanish and Russian language, from large databases and grey literature. PRP was in general an effective and safe treatment for degenerative LPB. Positive results were found in almost studies, a small number of adverse events were related, the risk of bias of the RCTs was low. Based on the evaluation of the included studies, we graded as level II the quality of the evidence supporting the use of PRP in LBP. Large-scale, multicenter RCTs are still needed to confirm these findings.

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.

Patients With Knee Osteoarthritis Who Receive Platelet-Rich Plasma or Bone-Marrow Aspirate Concentrate Injections Have Better Outcomes Than Patients Who Receive Hyaluronic Acid: Systematic Review and Meta-analysis

PURPOSE

To systematically review the literature in order to compare the efficacy and safety of platelet-rich plasma (PRP), bone marrow aspirate concentrate (BMAC), and hyaluronic acid (HA) injections for the treatment of knee osteoarthritis (OA).

METHODS

A systematic review was performed by searching PubMed, the Cochrane Library, and Embase to identify Level I studies that compared the clinical efficacy of at least 2 of the following 3 injection therapies: PRP, BMAC, and HA for knee OA. The search phrase used was knee AND osteoarthritis AND randomized AND ("platelet rich plasma" OR "bone marrow aspirate" OR "hyaluronic acid"). Patients were primarily assessed based on patient-reported outcome scores (PROs) including the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), visual analog scale (VAS) for pain, and Subjective International Knee Documentation Committee (IKDC) score.

RESULTS

Twenty-seven studies (all Level I) met inclusion criteria, including 1,042 patients undergoing intra-articular injection(s) with PRP (mean age 57.7 years, mean follow-up 13.5 months), 226 patients with BMAC (mean age 57.0 years, mean follow-up 17.5 months), and 1,128 patients with HA (mean age 59.0 years, mean follow-up 14.4 months). Non-network meta-analyses demonstrated significantly better post-injection WOMAC (p < 0.001), VAS (p < 0.01), and Subjective IKDC scores (p < 0.001) in PRP patients when compared to HA patients. Similarly, network meta-analyses demonstrated significantly better post-injection WOMAC (p < 0.001), VAS (p = 0.03), and Subjective IKDC (p < 0.001) scores in BMAC patients when compared to HA patients. There were no significant differences in post-injection outcome scores when comparing PRP to BMAC.

CONCLUSION

Patients undergoing treatment for knee OA with PRP or BMAC can be expected to experience improved clinical outcomes when compared to HA patients.

LEVEL OF EVIDENCE

I, Meta-Analysis of Level I studies.

The Use of Biologics in NFL Athletes: An Expert Consensus of NFL Team Physicians

Background

There is a lack of published information outlining the use of biologics in National Football League (NFL) athletes and limited data to guide biologic treatment strategies.

Purpose

To develop a consensus on the use of biologics among NFL team physicians.

Study Design

Consensus statement.

Methods

A working group of 6 experts convened a consensus process involving NFL team physicians using validated Delphi methodology. Physicians from 32 NFL teams as well as NFL London were invited to take part. This iterative process was used to define statements on the use of biologics in NFL athletes. A recent scoping review exploring biologics in professional athletes was used to inform the first of 3 rounds of surveys, with statements considered under 7 headings: biologics in general, challenges of treating NFL athletes, terminology/nomenclature, autologous blood products, cell-based therapies, guidance for NFL team physicians, and biologic research in the NFL. In addition to rating agreement, experts were encouraged to propose further items or modifications. Predefined criteria were used to refine item lists after each survey. For a consensus within the final round, defined a priori, items were included in the final information set if a minimum of 75% of respondents agreed and fewer than 10% disagreed.

Results

Physicians from 26 NFL teams and NFL London responded to the initial invitation to participate in the Delphi process; 88.9% of participating team physicians completed the round 1 survey, with response rates of 87.5% in round 2 and 95.2% in round 3. After 3 rounds, 47 statements reached a consensus. A consensus was achieved that platelet-rich plasma has a positive impact on patellar tendinopathy and on symptoms in early osteoarthritis but not for other indications. NFL team physicians agreed that while cell therapies have the potential to improve symptoms, the misrepresentation of uncharacterized preparations as "stem cells" has contributed to the widespread use of unproven therapies.

Conclusion

This study established an expert consensus on 47 statements relating to the use of biologics in NFL athletes. In addition to providing clinical guidance for the use of biologics in NFL athletes, this study identified key areas for future focus including the development of athlete education materials.

Research trends of platelet-rich plasma therapy on knee osteoarthritis from 2011 to 2021: A review

BACKGROUND

Platelet-rich plasma (PRP) has been widely used to alleviate osteoarthritis of the knee, and research results are abundant. However, there are no bibliometric reports in publications in this field. Therefore, the current status of PRP for the treatment of osteoarthritis of the knee from 2011 to 2021 was analyzed using Citespace 6.1.R2 software.

METHODS

Publications regarding PRP treating Knee Osteoarthritis between 2011 and 2021 were extracted from the Web of Science database. CiteSpace was used to analyze the number of publications, countries, institutions, journals, authors, cited references, and keywords by using standard bibliometric indicators.

RESULTS

A total of 988 publications were searched from 2011 to 2021. In the last decade, the number of publications has increased in the field. Brian J. Cole was the author with the most output, with 31 relevant articles, and Giuseppe Filardo ranked first in cited authors. Am J Sport Med was the most cited journal. In this field, the most prolific country is the United States and the most prolific institution is Rush University. An article published by Sandeep Patel ranked first in cited references with 118 citations. "Randomized controlled trial" was the most bursting keyword and other more popular keywords about PRP for knee osteoarthritis: "hyaluronic acid," "double-blind," and "mesenchymal stem cell."

CONCLUSION

This bibliometric study provides a decade of current clinical research on PRP for the treatment of osteoarthritis of the knee, which can help researchers understand the hot spots in the field and provide a new direction for their research.

Intra-articular injection of platelet-rich plasma in patients with hemophilia and painful knee joint cartilage degeneration

INTRODUCTION

Knee arthropathy causes pain to people with hemophilia (PWH). One of the current controversies is whether injections of intra-articular platelet-rich plasma (PRP) are effective in relieving the knee pain of PWH.

AREAS COVERED

A narrative literature review was conducted on the efficacy of PRP injections in the knees of PWH.

EXPERT OPINION

Intra-articular PRP knee injections are widely used in patients with knee osteoarthritis to relieve pain and delay total knee arthroplasty. Although numerous publications have supported the use of PRP in knee osteoarthritis, there is still major controversy regarding its true usefulness, given that a number of studies with a high degree of evidence have failed to show the efficacy of PRP. With respect to painful hemophilic arthropathy, the use of PRP injections is even more controversial, as there are only four publications on the subject supporting the use of PRP in hemophilia, all of them with a low degree of evidence. A publication with grade 1 evidence recommended against the use of PRP in hemophilic arthropathy because its efficacy has not been demonstrated. My opinion is that intra-articular PRP injections should not be used in hemophilia until there is more evidence of its benefits.

Comparison of clinical efficiency between intra-articular injection of platelet-rich plasma and hyaluronic acid for osteoarthritis: a meta-analysis of randomized controlled trials

Background

Platelet-rich plasma (PRP) and hyaluronic acid (HA) are non-surgical treatments for osteoarthritis (OA), but the comparison of their efficiency is still inconclusive.

Objectives

The objectives of this study were to compare the efficacy of PRP and HA in the treatment of OA by meta-analysis and to explore the effects of different injection times and leukocyte concentration on the efficacy of PRP.

Design

Meta-analysis and subgroup analysis were conducted. The data were analyzed by Review Manager v5.4.1.

Data sources and methods

Articles were retrieved and screened from PubMed, the Cochrane Library, Web of Science, and Embase. The outcome included the total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the visual analog scale (VAS), adverse events (AEs), the International Knee Documentation Committee (IKDC), and the satisfaction rate.

Results

A total of 30 articles involving 2733 patients were included. The total WOMAC score and IKDC score of the PRP group were better than those of the HA group at the last follow-up time, while there was no significant difference in AEs, satisfaction rate, and VAS between the two groups. In our subgroup analysis, there was no significant difference between single-injection PRP and triple-injection PRP. Leukocyte-poor PRP (LP-PRP) was better than leukocyte-rich PRP (LR-PRP) in IKDC, but there was no significant difference between them in the other scores.

Conclusions

In the treatment of OA, compared with HA, PRP performed better in the improvement of the patient's function. There was no significant difference in VAS and AEs between the two groups, and the safety was comparable. LP-PRP looked to be superior to LR-PRP in functional recovery, but there appeared to be no significant difference in pain relief between them. There was no significant difference between single PRP and triple PRP in the subgroup analysis.

Comparison of the clinical effectiveness of activated and non-activated platelet-rich plasma in the treatment of knee osteoarthritis: a systematic review and meta-analysis

INTRODUCTION/OBJECTIVES

Platelet-rich plasma (PRP) has shown to be clinically effective in the treatment of knee osteoarthritis (OA). Notwithstanding, some inconsistences remain due to methodological differences in PRP preparation such as the use (or not) of activation strategies. We aimed to evaluate whether the use of non-activated PRP would be as effective as activated PRP in patients with knee OA.

METHOD

All randomized, placebo-controlled trials were identified through a search in MEDLINE, EMBASE, Scopus, and Web of Science up to June 2022. Pre- and post-injection pain and function scores were collected. The meta-analysis was conducted with a random-effects model and generic inverse variance method. Effect sizes were estimated using standardized mean differences (SMD).

RESULTS

Fourteen clinical trials involving 1292 subjects were included for meta-analysis. Exogenous activation of PRP revealed a significant pain relief (SMD, - 1.05 [95% CI - 1.58 to - 0.52]; p = 0.0001) and a significant functional improvement (SMD, - 1.21 [95% CI - 1.75 to - 0.67]; p < 0.0001) unlike studies describing the use of a non-activated PRP. The sensitivity analysis indicated that the effect size for both outcomes was not influenced by a single study.

CONCLUSIONS

The results of this systematic review suggest that the use of an exogenously activated PRP is more effective in improving both pain and functional scores in patients with knee OA. Key Points • Results from meta-analysis suggest that exogenously activated PRP is clinically more effective than non-activated PRP. • The use of an activated PRP was more frequently reported by the included studies. • The most frequent method for activation was the use of calcium chloride (CaCl₂).

Modifying Orthobiological PRP Therapies Are Imperative for the Advancement of Treatment Outcomes in Musculoskeletal Pathologies

Autologous biological cellular preparations have materialized as a growing area of medical advancement in interventional (orthopedic) practices and surgical interventions to provide an optimal tissue healing environment, particularly in tissues where standard healing is disrupted and repair and ultimately restoration of function is at risk. These cellular therapies are often referred to as orthobiologics and are derived from patient's own tissues to prepare point of care platelet-rich plasma (PRP), bone marrow concentrate (BMC), and adipose tissue concentrate (ATC). Orthobiological preparations are biological materials comprised of a wide variety of cell populations, cytokines, growth factors, molecules, and signaling cells. They can modulate and influence many other resident cells after they have been administered in specific diseased microenvironments. Jointly, the various orthobiological cell preparations are proficient to counteract persistent inflammation, respond to catabolic reactions, and reinstate tissue homeostasis. Ultimately, precisely delivered orthobiologics with a proper dose and bioformulation will contribute to tissue repair. Progress has been made in understanding orthobiological technologies where the safety and relatively easy manipulation of orthobiological treatment tools has been demonstrated in clinical applications. Although more positive than negative patient outcome results have been registered in the literature, definitive and accepted standards to prepare specific cellular orthobiologics are still lacking. To promote significant and consistent clinical outcomes, we will present a review of methods for implementing dosing strategies, using bioformulations tailored to the pathoanatomic process of the tissue, and adopting variable preparation and injection volume policies. By optimizing the dose and specificity of orthobiologics, local cellular synergistic behavior will increase, potentially leading to better pain killing effects, effective immunomodulation, control of inflammation, and (neo) angiogenesis, ultimately contributing to functionally restored body movement patterns.

Swiss Medical Devices for Autologous Regenerative Medicine: From Innovation to Clinical Validation

Regenerative medicine, based on the use of autologous tissues and embryonic, stem or differentiated cells, is gaining growing interest. However, their preparation, in a manner compliant with good practices and health regulations, is a technical challenge. The aim of this manuscript is to present the design of reliable CE marked medical devices for the preparation of standardized platelet-rich plasma (PRP) and other autologous biologics intended for therapeutic uses. There are numerous PRP isolation processes. Depending on the methodology used, PRP composition varies greatly in terms of platelet concentration, platelet quality, and level of contamination with red and white blood cells. This variability in PRP composition might affect the clinical outcomes. The devices presented here are based on a specific technology, patented all over the world, that allows the precise separation of blood components as a function of their density using thixotropic separator gels in closed systems. This allows the preparation, in an automated manner, of leukocyte poor PRP with a standardized composition. Production of different forms of PRP is a clinical asset to suit various therapeutic needs. Therefore, we are offering solutions to prepare PRP either in liquid or gel form, and PRP combined with hyaluronic acid. These biologics have been successfully used in many different therapeutic domains, resulting in more than 150 published clinical studies. We also developed the CuteCell technology platform for cell culture expansion for further autologous cell therapies. This technology enables the safe and rapid in vitro expansion of cells intended for therapeutic use in good manufacturing practices (GMP) and autologous conditions, using blood-derived products as culture media supplementation. We summarize in this article our 20 years’ experience of research and development for the design of PRP devices and, more recently, for PRP combined with hyaluronic acid.

Intra-Articular Platelet-Rich Plasma Injections in Knee Osteoarthritis: A Review of Their Current Molecular Mechanisms of Action and Their Degree of Efficacy

Knee osteoarthritis (OA) is estimated to affect more than 10% of the population, with a lifetime risk of 45%. Contemporary guidelines advise control of body weight, therapeutic physical exercise, drug treatment (oral non-steroidal anti-inflammatory drugs, paracetamol, opioids), and mechanical aids (walking aids, braces, orthoses). Nevertheless, these treatments typically have only short-term benefits. Intra-articular corticosteroids are typically advised, but only for short-term pain alleviation, given that their benefits last only a few weeks. The efficacy of hyaluronic acid is controversial. When the aforesaid options fail, total knee arthroplasty is generally recommended as an efficacious treatment. However, it is costly and can involve medical and postoperative complications. Therefore, determining alternate safe and effective treatments for knee OA is paramount. Platelet-rich plasma (PRP) has lately been investigated for the treatment of knee OA. This article reviews recent knowledge concerning PRP’s molecular mechanisms of action. The effectiveness of intra-articular PRP injections in the knee joint remains controversial, although most recent publications show pain alleviation in the short term. Orthopedic surgeons treating people with knee OA are becoming increasingly interested in PRP, despite indecisive clinical data and basic science information. Further studies comparing PRP with placebo are required.