Comparison of two platelet rich plasma formulations with viscosupplementation in treatment of moderate grade gonarthrosis: A prospective randomized controlled study

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.

Comparison of hyaluronic acid and platelet-rich plasma in knee osteoarthritis: a systematic review

BACKGROUND

Knee osteoarthritis (KOA) is a common joint disorder, and intra-articular injections of hyaluronic acid (HA) or platelet-rich plasma (PRP) are frequently employed therapeutic interventions. However, there remains controversy regarding their efficacy. This systematic review aims to compare the effectiveness and safety of HA and PRP through a meta-analysis, with the objective of identifying the optimal treatment protocol for KOA and enhancing its management.

METHODS

Randomized controlled trials evaluating the clinical outcomes of patients receiving intra-articular injections of either HA or PRP were included as eligible studies. Two independent investigators assessed the selected studies and evaluated their risk of bias. Primary outcome measures included the Visual Analog Scale (VAS) score, the Western Ontario and McMaster Universities Arthritis Index (WOMAC) score, and other relevant assessment indices. Dichotomous variables were analyzed using risk ratios (RR) with 95% confidence intervals (CI). Data analysis was conducted using RevMan software (version 5.3).

RESULTS

A total of forty-two randomized controlled trials were included in this meta-analysis. No significant differences were observed between the patient populations in the two groups. The analysis demonstrated that PRP resulted in lower VAS and WOMAC scores compared to HA. Additionally, PRP exhibited superior performance across other evaluation indices. Notably, the incidence of adverse events was higher in the PRP group; however, all reported complications were mild.

CONCLUSIONS

Based on the current evidence, intra-articular injection of PRP appears to be more effective than HA for the treatment of KOA, as indicated by the analysis of VAS, WOMAC scores, and other evaluation indices.

TRIAL REGISTRATION

Retrospectively registered.

Comparison of Different Molecular Weights of Intra-Articular Hyaluronic Acid Injections for Knee Osteoarthritis: A Level I Bayesian Network Meta-Analysis

Background: The present Bayesian network meta-analysis compared the efficacy of intra-articular injections of different molecular weights of hyaluronic acid (HA) in patients with knee osteoarthritis. Methods: In November 2024, the following databases were accessed: PubMed, Web of Science, Google Scholar, and Embase. All randomised controlled trials investigating the efficacy of intra-articular HA injections for knee osteoarthritis were accessed. The outcome of interest was to evaluate pain according to the visual analogue scale (VAS). The groups included for comparison were the ultra-high molecular weight (UHMW), high molecular weight (HMW), medium molecular weight (MMW), and low molecular weight (LMW). Results: Data from 9822 patients were collected. The mean age of the patients was 62.1 ± 5.0 years with given comparability at baseline. Different follow-up periods were compared. The longest control period ranged from four to six months, and the UHMW and HMW injections were the interventions associated with the greatest reduction in the VAS. LMW HA was the intervention associated with the lowest decrease in VAS, falling short of the control group. Conclusions: The main findings of the present Bayesian network meta-analysis, with a current level I of evidence, suggests that the UHMW and HMW HA has a beneficial effect on pain at 6 months post intervention in patients with knee osteoarthritis.

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).

Platelet-rich plasma intra-articular knee injections from open preparation techniques do not pose a higher risk of joint infection: A systematic review of 91 randomized controlled trials and 5914 injections

Purpose

To compare the infection rate of intraarticular platelet-rich plasma (PRP) knee injections between open and closed techniques in randomized controlled trials (RCTs) published in the last decade.

Methods

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, PubMed, Scopus and Virtual Health Library were accessed in October 2022 using the terms 'platelet-rich plasma', 'PRP', 'knee' and 'tibiofemoral' alone and in combination with Boolean operators AND/OR. RCTs published during the last 10 years evaluating PRP intra-articular knee injections were considered eligible. Studies were excluded if the kit/preparation technique was not described. Data were presented using individual studies' absolute values, totals, and pooled percentages. Publication bias was assessed using the ROBIS tool.

Results

Ninety-one studies met the predetermined eligibility criteria. Forty-one implemented a closed technique, while 50 were open. All studies implementing a closed technique disclosed their commercial kits. Only 16 studies (17.58%) failed to report joint infections. Among the studies reporting joint infections as outcomes, 30 implemented a closed technique with 1195 patients, 1921 intra-articular knee injections and 95.44% of patient follow-up. On the other hand, 45 of them implemented an open technique with 2290 patients, 3993 intra-articular knee injections and 97.07% of patient follow-up. No patient had a joint infection among the included studies. Thirty-three studies prepared their PRP in controlled environments (36.26%). Most studies did not report where the preparation occurred (48.35%). Only twelve studies disclosed using laminar flow during preparation (13.19%). The infection rate for both techniques was 0 per 1000 knee injections.

Conclusion

Open PRP preparation techniques do not pose a higher risk of joint infection and can lower manufacturing costs when appropriate facilities are available. However, PRP preparation setting and laminar flow implementation data are deficient, and minimal requirements for good manufacturing practices demand further studies while adhering to local and regional regulations.

Level of Evidence

Level I, systematic review of RCTs.

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.

Non-operative Treatment Options for Osteoarthritis in the Hip

With the increased disability associated with osteoarthritis (OA) progression, and the significant socioeconomic burden of joint replacement surgeries, there is a need for more reliable conservative treatments for patients presenting with hip OA. Most studies of OA treatments involve the knee. We conducted a literature search and reviewed non-operative hip OA treatment recommendations by the Osteoarthritis Research Society International, the American College of Rheumatology, American Academy of Orthopedic Surgeons, and European Alliance of Associations for Rheumatology, as well as Cochrane Reviews. Non-steroidal anti-inflammatory drugs and corticosteroid injections are the most supported and recommended options for hip OA; other medications with potential benefits for short-term pain relief include acetaminophen and tramadol. Most societies recommend against the use of glucosamine, typical opioids, and viscosupplementation injections. Platelet-rich plasma has potential benefits, but evidence of its effectiveness is incomplete. Further research is needed to better inform and guide clinicians who create treatment plans for patients with symptomatic hip OA.

How Does Platelet-Rich Plasma Compare Clinically to Other Therapies in the Treatment of Knee Osteoarthritis? A Systematic Review and Meta-analysis

BACKGROUND

There has been an increase in interest in the use of biological therapies in orthopaedic conditions such as knee osteoarthritis. Platelet-rich plasma (PRP) is one of these therapies, but it still lacks consistent results.

PURPOSE

To evaluate the effects (benefits and harms) of PRP intra-articular injection compared with other nonsurgical methods for the treatment of knee osteoarthritis.

STUDY DESIGN

Systematic review and meta-analysis of randomized and quasi-randomized controlled trials; Level of evidence, 2.

METHODS

Three electronic databases were searched to identify relevant studies published before January 2021. The primary outcomes were pain, function, and failure of treatment. Risks of bias of all trials were assessed using a Cochrane risk of bias tool. The Grading of Recommendations Assessment, Development and Evaluation System was used to assess the quality of evidence of included studies.

RESULTS

A total of 40 studies with 3035 participants were included. Analysis of this review focused on comparing PRP with hyaluronic acid, corticosteroid, and saline, as we believe they are the most relevant comparisons with the most studies available. At 6-month follow-up, PRP was as effective as and in some studies more effective than other therapies regarding pain, function, and stiffness. However, current evidence is of low or very low quality and is based on trials with high risk of bias and great heterogeneity among them. No significant difference among treatments was found concerning major adverse events and treatment failure.

CONCLUSION

Although studies suggest that PRP may be more effective than or at least as effective as other modalities of nonsurgical treatment for knee osteoarthritis in terms of pain, function, and adverse events, serious limitations and methodological flaws are considerable in the current literature. Therefore, the authors are not able to make recommendations for clinical practice regarding PRP for knee osteoarthritis.

Composition of Platelet-Rich Plasma Prepared From Knee Osteoarthritic Patients: Platelets, Leukocytes, and Subtypes of Leukocyte

INTRODUCTION

Platelet-rich plasma (PRP) has gained increasing popularity in the orthopedic field. There has been still no consensus on PRP preparation technique, thus providing a variety of final PRP products. Different preparation techniques lead to different compositions of PRP, which include platelet concentration, the number of leukocytes, and their subtypes. Here, we studied those compositions of PRP compared to whole blood samples.

METHODS

There were 335 participants who met the inclusion and exclusion criteria. Each participant underwent a blood drawing process to prepare PRP for their knee osteoarthritis treatment. We categorized baseline platelet concentration in whole blood samples into three groups: less than 2 x 10⁵/µL (Group 1), between 2 x 10⁵/µL and 2.99 x 10⁵/µL (Group 2), and greater than 2.99 x 10⁵/µL (Group 3). The primary outcome was reported as the platelet concentration in PRP and the ratio of platelet concentration in PRP compared to baseline whole blood samples. The secondary outcome was reported as the ratios of leukocyte, lymphocyte, and neutrophil in PRP compared to the baseline whole blood samples.

RESULTS

The average platelet concentration in PRP was 1.26 x 10⁶/µL (6.3 times higher compared to baseline whole blood samples). The mean platelet concentration of PRP in Group 1, Group 2, and Group 3 was 1.08 x 10⁶/µL, 1.38 x 10⁶/µL, and 1.71 x 10⁶/µL, respectively (p-value = 0.0001). The platelet concentration ratio of PRP condition to the baseline whole blood was 6.9, 5.8, and 4.2 in Group 1, Group 2, and Group 3, respectively (p-value = 0.0018). The average ratio of leukocytes in PRP to whole blood was 1.5. The average ratio of lymphocytes and neutrophils in PRP to whole blood was 2.0 and 0.5, respectively.  Conclusion: Different baseline platelet concentrations in whole blood samples provided significantly different platelet concentrations in PRP. The baseline platelet concentration in whole blood also provided an inverse relation to the fold change of the platelet concentration in PRP. Subtypes of leukocytes changed from neutrophil-predominated in the baseline whole blood samples to lymphocyte-predominated in PRP.

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.

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.

Efficacy and safety of platelet-rich plasma combined with hyaluronic acid versus platelet-rich plasma alone for knee osteoarthritis: a systematic review and meta-analysis

Purpose

To systematically evaluate the curative efficacy and safety of platelet-rich plasma (PRP) combined with hyaluronic acid (HA) in the treatment of knee osteoarthritis (KOA), comparing with platelet-rich plasma alone.

Methods

Cochrane Library, PubMed, China National Knowledge Infrastructure (CNKI) and Embase were searched for randomized controlled trials (RCTs) and cohort studies regarding the efficacy and safety of platelet-rich plasma (PRP) combined with hyaluronic acid (HA) in the treatment of knee osteoarthritis (KOA) comparing with platelet-rich plasma alone before January 15, 2022. The methodological quality of the ultimately included studies was assessed comprehensively, and meta-analysis was implemented using RevMan 5.3 software.

Results

Thirteen articles (9 RCTs, 4 cohort studies), including 1118 patients, were covered. There was no significant difference between the PRP + HA therapy and PRP-alone therapy in VAS scores at 3 months, 6 months and 12 months, WOMAC total scores at 3 months and KOOS at 1 month and 6 months. Compared with PRP-alone therapy, PRP + HA therapy was associated with significantly better improvement in VAS scores at 1 month, WOMAC total scores at 6 months, KOOS at 3 months, IKDC scores at 6 months and Lequesne index scores at 3 and 6 months. However, the smallest treatment effect of VAS scores, WOMAC total scores, KOOS and IKDC scores did not exceed the minimum clinically important difference (MCID). However, PRP + HA therapy got a greater reduction in the rate of adverse events, compared with PRP-alone therapy.

Conclusion

The results of this meta-analysis indicated that PRP + HA therapy was not found to be superior to PRP-alone therapy in pain relief and function improvement for patients with KOA. However, combined PRP with HA injections was generally safer than PRP injections alone, by assessing the incidence of adverse events.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-03398-6.

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

INTRODUCTION

Platelet-rich plasma (PRP) has gained popularity as a treatment option for knee osteoarthritis; however, its efficacy remains controversial. The optimal leukocyte concentration and number of injections have not been well investigated. This study was, therefore, designed to provide clinical evidence on the leukocyte concentration and number of intra-articular injections of PRP via a meta-analysis of randomized controlled trials (RCTs).

METHODS

The MEDLINE, Embase, Cochrane Library, CINAHL, and Scopus databases were searched and RCTs comparing PRP and hyaluronic acid (HA) for treating knee osteoarthritis were included. Clinical outcomes, including visual analog scale (VAS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and adverse reactions, were evaluated.

RESULTS

A total of 138 studies were screened, of which 21 level 1 RCTs (2086 knees; 1077 PRP and 1009 HA) were included. PRPs showed significant improvement in pain according to the VAS score compared to HA at 6 and 12 months, regardless of leukocyte concentration. Both single and multiple injections of PRP improved pain better than HA at 12 months. Regarding function, both single and multiple injections of leukocyte-poor PRP and leukocyte-rich PRP led to significantly better improvement in total WOMAC score compared with HA at 6 months. There was no significant difference in procedure-related knee pain or swelling between the PRP and HA groups. Leukocyte-rich PRP had a significantly higher odds ratio for procedure-related knee pain or swelling compared to HA (odds ratio, 3.3 [95% confidence interval, 1.1-10.2], P = .037).

CONCLUSION

Based on evidence from Level 1 studies, intra-articular injection of PRP improves pain and function in patients with knee osteoarthritis for up to 12 months and is superior to HA, regardless of leukocyte concentration or number of injections. The findings of this study support the routine clinical use of intra-articular injections of PRP for the treatment of knee osteoarthritis, regardless of the type and frequency of PRP injection.

LEVEL OF EVIDENCE

Meta-analysis of level I studies.

Bibliometric analysis of the top 50 highly cited articles on platelet-rich plasma in osteoarthritis and tendinopathy

The primary goal of this study was to compile the top 50 most cited articles on the use of platelet-rich plasma (PRP). A search of relevant studies was performed in accordance with the PRISMA guidelines in Web of Science. The top 25 most cited articles in osteoarthritis and tendinopathy were then compiled and evaluated. Level 1 evidence articles constituted the majority of the studies (64%) and were more likely to have a higher citation density. Altmetric data was highest for level 1 systematic reviews. Of the articles that report a positive outcome for PRP, 13% (2/16) had low risk of bias. This study defines the most cited and influential publications regarding PRP to further research in this area.

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

BACKGROUND

It is hypothesized that leukocyte-poor (LP) platelet-rich plasma (PRP) is preferred over leukocyte-rich (LR) PRP for the treatment of knee osteoarthritis (OA).

METHODS

The MEDLINE, Embase, and Cochrane databases were reviewed for all English-language studies comparing LP-PRP or LR-PRP with relevant controls or each other. The follow-up periods were 6 months and 12 months. The primary outcome measure was the change in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score between baseline and follow-up. The secondary outcome measures were changes in the WOMAC pain subscale, visual analog scale (VAS) for pain, and International Knee Documentation Committee (IKDC) subjective score between baseline and follow-up, and the incidence of local adverse reactions. Treatment outcomes were analyzed using the mean difference between treatments for continuous outcomes and the odds ratio for binary outcomes, with 95% credibility intervals. Treatment modalities were ranked using the surface under the cumulative ranking (SUCRA) probabilities. Risk of bias was assessed using the relevant Cochrane tools, RoB 2 (version 2 of the Cochrane risk-of-bias tools) for randomized controlled trials (RCTs) and ROBINS-I (Risk of Bias in Non-Randomized Studies - of Interventions) for prospective comparative studies (PCSs).

RESULTS

This network meta-analysis included 23 studies: 20 RCTs and 3 PCSs, with a total of 2,260 patients and a mean follow-up period of 9.9 months. The overall risk-of-bias assessment of the RCTs revealed that 9 studies had low risk, 7 had some concerns, and 4 had high risk. The overall risk-of-bias assessment of the PCSs revealed that 1 study had low risk and 2 had moderate risk. We found no significant (p < 0.05) difference in all outcome measures and local adverse reactions between LP-PRP and LR-PRP. SUCRA rankings revealed that, for all outcome measures, LP-PRP is preferred to LR-PRP across follow-up periods.

CONCLUSIONS

Leukocyte concentration of PRP does not play a significant role in patient-reported outcome measures for knee OA. LP-PRP is preferred to LR-PRP according to SUCRA rankings, but this preference may not be important in clinical practice.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

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).

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.

Efficacy of different platelet-rich plasma injections in the treatment of mild-moderate knee osteoarthritis: A systematic review and meta-analysis

AIMS

This study aimed to compare the efficacy of different numbered sets of injections of platelet-rich plasma (PRP) in the treatment of mild-moderate knee osteoarthritis (OA).

METHODS

A comprehensive search in three databases of Cochrane Library, Embase, and PubMed was conducted to find relevant articles that investigated the efficacy of PRP injection therapies in the treatment of mild-moderate knee OA through August 2020. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function scores were the primary outcomes and visual analogue scale (VAS) was the secondary outcome. The pooled improvements amongst different injection therapies were compared.

RESULTS

No significant differences in the improvement of WOMAC pain were observed amongst 1-, 2-, and 3-injection therapies at 3- (P = .26) and 6-month (P = .13) follow-ups. For a 12-month follow-up, the difference amongst different therapies reached borderline significance (P = .05) in which 3-injection therapy had a significantly better improvement than 2-injection therapy (P = .02) and reached borderline significance compared with 1-injection (P = .07). However, no significant differences in the improvement of VAS scores were observed amongst three injection therapies for all the follow-up visits (P > .05). For WOMAC function score, 3-injection therapy performed significantly better than 1-injection (P < .00001) or 2-injection therapy (P < .0001) only at 12-month follow-up visit.

CONCLUSIONS

Our results demonstrated that 3-injection therapy of PRP in the treatment of mild-moderate knee OA had the best efficacy in pain relief and function improvement compared with 1- and 2-injection therapies.

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.