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

Efficacy of intra-articular injections for the treatment of osteoarthritis: A narrative review

Osteoarthritis (OA) is a prevalent degenerative joint disease characterized by progressive cartilage loss, inflammation, and joint dysfunction. With profound effects on joint function and quality of life, OA imposes a substantial socio-economic burden. As of now, OA remains incurable, lacking approved medications, regenerative therapies, or procedures that can halt the progressive destruction of the joint. Intraarticular (IA) injections have emerged as a cornerstone in the management of knee OA, offering localized minimally invasive therapeutic options. Traditional IA therapies, including corticosteroids and hyaluronic acid (HA), primarily aim to reduce pain but lack regenerative capacity. Biologic IA therapies for knee OA including autologous blood-derived products like platelet-rich plasma (PRP), bone marrow aspirate concentrate (BMAC) and mesenchymal stromal cells (MSCs) have become more commonly used. Finally, newer IA therapies such as fibroblast growth factor 18 and gene therapy are being investigated. In this review, we highlight the current evidence around IA injections for the treatment of knee OA.

Randomized Controlled Trials Studying Nonoperative Treatments of Osteoarthritis Often Use Misleading and Uninformative Control Groups: A Systematic Review

BACKGROUND

Because there are no known treatments that alter the natural course of the pathophysiology of osteoarthritis, nonoperative treatment needs to be compared with known effective treatments that seek to mitigate symptoms or with similarly invasive inert (placebo) treatments to determine effectiveness. Comparing a treatment to an uninformative control group may inappropriately legitimize and support the use of potentially ineffective treatments. We therefore investigated the prevalence of inappropriate control groups in musculoskeletal research and asked whether these are associated with reporting a positive treatment effect.

QUESTIONS/PURPOSES

We systematically reviewed randomized trials of nonoperative treatments of osteoarthritis and asked: (1) What proportion of randomized trials use uninformative control groups (defined as a treatment less invasive than the tested treatment, or a treatment that might possibly not outperform placebo but is not acknowledged as such)? (2) Is the use of uninformative control groups independently associated with reporting a positive treatment effect (defined as p < 0.05 in favor of the intervention, or as making a recommendation favoring the intervention over the control treatment)?

METHODS

In a systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we searched PubMed, Cochrane, and Embase up to September 2023 for randomized controlled trials published between 2020 to 2022 that compared one or more nonoperative treatments for the symptoms of osteoarthritis. We excluded studies that contained a surgical treatment group. We identified 103 trials that met eligibility criteria, with a total of 15,491 patients. The risk of bias was high in 60% (n = 62) of trials using the Cochrane Risk of Bias Tool, version 2. Although the high risk of bias in the included studies is concerning, it does not invalidate our design; instead, it highlights that some studies may use flawed methods to recommend treatments with unproven effectiveness beyond nonspecific effects because the kinds of bias observed would tend to increase the apparent benefit of the treatment(s) being evaluated. We used logistic regression to test the association of uninformative control groups with a positive treatment effect, accounting for potential confounders such as conflict of interest and study bias using the Cochrane Risk of Bias score.

RESULTS

The use of uninformative control groups (treatments less invasive than the tested treatment, or treatments that might not outperform placebo but are not acknowledged as such) was found in 46% (47 of 103) of included studies. After accounting for potential confounding, there was no association between reporting positive treatment effects and the use of an uninformative control group. Studies with a low risk of bias had a lower likelihood of reporting a positive treatment effect (OR 0.2 [95% confidence interval 0.05 to 0.9]; p = 0.04, model pseudo R 2 = 0.21).

CONCLUSION

The finding that recent studies that mimic high-level evidence often use uninformative control groups that do not adequately account for nonspecific effects (perceived treatment benefits unrelated to a treatment's direct physiological effects) points to a high risk of legitimizing ineffective treatments. This raises the ethical imperative for patients, clinicians, journal peer reviewers, and journal editors to hold researchers to the standard of an adequate, informative control group. Awareness and risk of bias checklists might help patients and clinicians forgo new treatments based on seemingly high-level evidence that may carry only iatrogenic, financial, and psychological harm (false hope, in particular).

LEVEL OF EVIDENCE

Level I, therapeutic 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.

Most Publications Regarding Platelet-Rich Plasma Use in the Knee Are From Asia, Investigate Injection for Osteoarthritis, and Show Outcome Improvement: A Scoping Review

PURPOSE

To evaluate and synthesize the available literature related to platelet-rich plasma (PRP) treatment of knee pathologies and to provide recommendations to inform future research in the field.

METHODS

PubMed, CINAHL, and Scopus databases were queried on October 6, 2023. All identified citations were collated and uploaded into Covidence for screening and data extraction. Studies were included if they were human studies published in English with adult cohorts that received PRP as a procedural injection or surgical augmentation for knee pathologies with patient-reported outcome measures (PROMs) and level of evidence Levels I-IV.

RESULTS

Our search yielded 2,615 studies, of which 155 studies from 2006 to 2023 met the inclusion criteria. Median follow-up was 9 months (±11.2 months). Most studies (75.5%) characterized the leukocyte content of PRP, although most studies (86%) did not use a comprehensive classification scheme. In addition, most studies were from Asia (50%) and Europe (32%) and were from a single center (96%). In terms of treatment, 74% of studies examined PRP as a procedural injection, whereas 26% examined PRP as an augmentation. Most studies (68%) examined treatment of knee osteoarthritis. Many studies (83%) documented significant improvements in PROMs, including 93% of Level III/IV evidence studies and 72% of Level I/II evidence studies, although most studies (70%) failed to include minimal clinically important difference values. The visual analog scale was the most-used PROM (58% of studies), whereas the Short Form Health Survey 36-item was the least-used PROM (5% of studies).

CONCLUSIONS

Most published investigations of knee PRP are performed in Asia, investigate procedural injection for osteoarthritis, and show significant outcome improvements. In addition, this review highlights the need for better classification of PRP formulations.

LEVEL OF EVIDENCE

Level IV, scoping review of Level I-IV studies.

Effect of platelet-rich plasma versus placebo or corticosteroid for knee osteoarthritis: A systematic review and meta-analysis of randomized controlled trials

Background

The effectiveness of intra-articular platelet-rich plasma (IA-PRP) injections for managing pain in knee osteoarthritis (KOA) remains inconsistent. Therefore, this study aimed to systematically review randomized controlled trials (RCTs) assessing the efficacy of IA-PRP.

Methods

A total of 21 studies meeting the inclusion criteria were selected from various scientific databases, all of which compared PRP to either a placebo or an active comparator, such as corticosteroids (CS), in the treatment of KOA. Weighted mean differences (WMDs) for the Visual Analogue Scale (VAS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the Knee Injury and Osteoarthritis Outcome Score (KOOS), along with their 95 % confidence intervals (CIs), were calculated for each study. A subgroup analysis was conducted for the pain scores, comparing leukocyte-poor and leukocyte-rich PRP with either a placebo or CS. The evidence was synthesized using a random-effects meta-analysis.

Results

There were 2406 participants in all included studies; 1223 were in the PRP versus placebo group and 1183 were in the PRP versus corticosteroid group. The IA-PRP showed significant improvement of VAS, and WOMAC scores compared to placebo (P < 0.00.05), except KOOS score (P > 0.05). All pain scores were highly sinficant improved with IA-PRP, compared to IA-CS (P < 0.05). Additionally, the leukocyte rich PRP was efficasious than leukocyte poor PRP (P < 0.05) improving the all pain scores at the 6-month follow-up.

Conclusions

PRP treatment showed better results than placebo and corticosteroids in terms of reducing pain and improving function in KOA patients. Furthermore, lecocyte rich PRP is more effective than lecocyte poor PRP [PROSPERO, CRD42024540507].

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.

Randomized Controlled Trials for Platelet-Rich Plasma Use in Knee Osteoarthritis Rarely Report Key Sociodemographic Patient Variables: A Scoping Review

Purpose

To investigate the characteristics and rate of sociodemographic variables reported in randomized controlled trials (RCTs) studying platelet-rich plasma (PRP) injections in the treatment of knee osteoarthritis (OA).

Methods

In January 2024, PubMed, Scopus, and Web of Science databases were queried for the phrase "Platelet-Rich Plasma Knee Osteoarthritis." Included studies were RCTs investigating PRP use in knee OA published in English between 2012 and 2023. Each RCT was inspected for patient age and sex or gender as well as the following sociodemographic variables: race, ethnicity, insurance status, income, housing status, work status, and education. Data were presented in a descriptive fashion and analyzed using χ2 test and Fisher's exact test to compare 2 and 3 categorical variables, respectively, with significance defined as P < .05.

Results

From 2012 through 2023, 71 RCTs met inclusion criteria. Included publications reported both age and sex or gender in 71/71 papers (100%). Reporting rates for other sociodemographic variables were as follows: race (3/71, 4.23%), work status (5/71, 7.04%), and education (3/71, 4.23%). No studies included the ethnicity, insurance status, income, or housing status of the enrolled patients. There was no difference in reporting sociodemographic variables by journal (P = .083) or by year of publication (P = .340). Sociodemographic variables were reported significantly less frequently than age and sex or gender (P < .001).

Conclusions

In this study, we found that age and sex or gender are always reported in RCTs of PRP use for knee OA. However, other sociodemographic variables, such as race, work status, and education, that may be important to understand are rarely reported.

Clinical Relevance

Sociodemographic variables may affect outcomes in knee osteoarthritis. It is important to understand which of these variables are most studied and which variables are most overlooked. This will help us better understand the quality of the available information.

Orthobiologics in knee osteoarthritis, dream or reality?

Cartilage restoration or repair, also known as orthobiologic therapy, is indicated after the failure of conservative or supportive treatment. However, there is paucity in evidence supporting the efficacy of orthobiologic therapy. The blood-derived products, such as platelet-rich plasma (PRP), is one of the commonly used orthobiologic therapy for knee osteoarthritis. Several studies have shown that PRP is superior to other treatments, but the anatomic changes are scarce. Treatment with mesenchymal stem cells (MSCs) offers the greatest potential for curing degenerative disease due to their self-renewal ability, ability to migrate towards injured tissues (homing/trafficking), and ability to promote repair and regeneration of osteochondral defects. However, ethical concerns and high costs remain major challenges associated with MSC therapy. Gene therapy, another promising orthobiologic therapy, is currently in phase II clinical trial and has shown promising results. The key factors for successful orthobiologic therapy include patient selection, appropriate dosing, treatment of underlying mechanical problems, age, severity, and cost-effectiveness.

Efficacy of Platelet-Rich Plasma Intra-articular Injections in Hip and Knee Osteoarthritis

Osteoarthritis (OA) is a chronic degenerative disorder that causes significant pain and functional limitations. Platelet-rich plasma (PRP) therapy has gained considerable attention in recent years in the treatment of musculoskeletal injuries. In this narrative review, we aim to investigate the role of intra-articular PRP injections in the treatment of knee and hip OA. The review also discusses different classifications of PRP based on composition. Furthermore, this narrative review also identified various limitations of PRP therapy in OA. PRP is classified into different types based on cell content and fibrin architecture, including pure platelet-rich plasma (P-PRP), leukocyte- and platelet-rich plasma (L-PRP), pure platelet-rich fibrin (P-PRF), and leukocyte- and platelet-rich fibrin (L-PRF). Various clinical trials have shown that PRP is an effective option for the treatment of knee and hip OA. However, the superiority of PRP over hyaluronic acid has been reported inconsistently. This variability can be attributed to PRP preparation techniques. The safety profiles of PRP are generally favorable and the adverse effects are generally mild in nature. Although there is sufficient evidence in support of PRP in the treatment of OA, the long-term effects of PRP have not been reported. Further studies should focus on longer follow-up periods to identify the efficacy and safety of PRP in treating knee OA. There is also a need for standardization of PRP preparations in OA management.

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.

Allogeneic platelet-rich plasma for knee osteoarthritis in patients with primary immune thrombocytopenia: A randomized clinical trial

The treatment of painful KOA in adult patients with ITP has not been well studied yet. We conducted a prospective, double-blind, randomized, placebo-controlled trial to evaluate the efficacy of intra-articular allogeneic PRP injections on symptoms and joint structure in patients with KOA and ITP. 80 participants were randomly allocated in a 1:1 ratio to allogeneic PRP group or saline group. The primary outcome was the WOMAC total score at 12 months post-injection. The number of patients in each group who achieved MCID of primary outcome showed a statistically significant difference only at 3-month (27/39 vs. 5/39, p = 0.001) and 6-month (15/39 vs. 3/38, p = 0.032). The difference in WOMAC total score exceeded the MCID only at 3 month (mean difference of -15.1 [95% CI -20.7 to -9.5], p < 0.001). Results suggest that allogeneic PRP was superior to placebo only with respect to symptoms at 3-month of follow-up.

American Academy of Orthopaedic Surgeons Technology Overview Summary: Platelet-Rich Plasma (PRP) for Knee Osteoarthritis

The Platelet-Rich Plasma (PRP) for Knee Osteoarthritis Technology Overview is based on a systematic review of current scientific and clinical research. Through analysis of the current best evidence, this technology overview seeks to evaluate the efficacy of PRP for patients with knee osteoarthritis. The systematic literature review resulted in 54 articles: 36 high-quality and 18 moderate-quality. The findings of these studies were summarized to present findings on PRP versus control/placebo, acetaminophen, non-steroidal anti-inflammatory drugs, corticosteroids, exercise, prolotherapy, autologous conditioned serum, bone marrow aspirate concentrate, hyaluronic acid, and ozone therapy. In addition, the work group highlighted areas that needed additional research when evidence proved lacking on the topic and carefully noted the potential harms associated with an intervention, required resource utilization, acceptability, and feasibility.

Comparative effectiveness of intra-articular therapies in knee osteoarthritis: a meta-analysis comparing platelet-rich plasma (PRP) with other treatment modalities

INTRODUCTION

Knee osteoarthritis (KOA) is a progressive joint disease commonly treated with intra-articular injections, including platelet-rich plasma (PRP), hyaluronic acid (HA), or corticosteroids (CS). This updated meta-analysis aims to enhance the statistical power of the results and provide comprehensive clinical evidence that reflects the most current research. By doing so, the authors aim to suggest a reliable estimate for the development of guidelines, addressing the pressing need for effective and minimally invasive treatment options.

METHODS

PubMed, Scopus, clinicaltrials.gov, Cochrane Central were searched until March 2023, for randomized controlled trials (RCTs) comparing the effectiveness of intra-articular injectable therapies, including PRP, HA, CS, and placebo, in KOA. Data extraction involved baseline characteristics and outcome measures [Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores, Visual Analog Scale (VAS) pain scores, KOOS, and IKDC scores] at 1, 3, 6 and 12 months. Statistical analysis, including subgroup analysis, assessment of heterogeneity, and publication bias, was conducted using Review Manager.

RESULTS

Our meta-analysis of 42 studies involving 3696 patients demonstrated that PRP treatment resulted in significant pain relief compared to HA injections, as evidenced by improved WOMAC pain (MD: -0.74; 95% CI: -1.02 to -0.46; P≤0.00001; I 2=94%) and VAS pain (MD: -0.65; 95% CI: -1.24 to -0.06; P=0.03; I2=97%) outcomes. Similarly, PRP showed greater efficacy in reducing WOMAC pain (MD: -8.06; 95% CI: -13.62 to -2.51: P=0.004; I 2=96%) and VAS pain (MD: -1.11; 95% CI: -1.64 to -0.59; P≤0.0001; I 2=68%) compared to CS injections, with the most significant improvement observed at 6 months.

CONCLUSIONS

PRP is an effective treatment for KOA. It provides symptomatic relief, has the potential to reduce disease progression, and has sustained effects up to 12 months. PRP offers superior pain relief and functional enhancement compared to CS and HA injections.

The Influence of Industry Affiliation on Randomized Controlled Trials of Platelet-Rich Plasma for Knee Osteoarthritis

BACKGROUND

Industry funding and corporate sponsorship have played a significant role in the advancement of orthopaedic research and technology. However, this relationship raises concerns for how industry association may bias research findings and influence clinical practice.

PURPOSE

To determine whether industry affiliation plays a role in the outcomes of randomized controlled trials (RCTs) investigating platelet-rich plasma (PRP).

STUDY DESIGN

Meta-analysis; Level of evidence, 2.

METHODS

A search of the PubMed, Cochrane, and MEDLINE databases for RCTs published between 2011 and the present comparing PRP versus hyaluronic acid, corticosteroid, or placebo for the treatment of knee osteoarthritis was performed. To determine industry affiliation, the conflict of interest, funding, and disclosure sections of publications were assessed, and all authors were assessed through the American Academy of Orthopaedic Surgeons disclosure database and the Centers for Medicare & Medicaid Services open payments database. Studies were classified as industry affiliated (IA) or non-industry affiliated (NIA). The outcomes of each study were rated as favorable, analogous, or unfavorable according to predefined criteria.

RESULTS

A total of 37 studies (6 IA and 31 NIA) were available for analysis. Overall, 19 studies (51.4%) reported PRP as favorable compared with other treatment options, while 18 studies (48.6%) showed no significant differences between PRP and other treatment methods. There was no significant difference in qualitative conclusions between the IA and NIA groups, with the IA group having 3 favorable studies and 3 analogous studies and the NIA group having 16 favorable studies and 15 analogous studies (P = .8881). When comparing IA versus NIA studies using 6- and 12-month Western Ontario and McMaster Universities Arthritis Index and International Knee Documentation Committee scores, there were no significant differences in outcomes.

CONCLUSION

The results of this study demonstrated that qualitative conclusions and outcome scores were found to not be associated with industry affiliation. Although the results of this study suggest that there is no influence of industry involvement on RCTs examining PRP, it is still necessary to carefully evaluate pertinent commercial affiliations when reviewing recommendations from studies before adopting new treatment approaches, such as the use of PRP for knee osteoarthritis.

Inflammatory ultrasound features as prognostic factors of pain and functional outcomes following intra-articular platelet-rich plasma in knee osteoarthritis

AIM

To explore inflammatory ultrasound predictors of improvements in pain and function over 2, 6, and 12 months following administration of intra-articular platelet-rich plasma (PRP) in knee osteoarthritis (OA).

METHOD

Patients with painful mild-moderate radiographic knee OA from a subset of the RESTORE RCT underwent ultrasound assessment according to the standardized OMERACT scanning protocol to detect inflammatory features such as synovitis, synovial hypertrophy, and effusion with power Doppler. The study knee was treated with 3 once-weekly PRP injections obtained after centrifugation at 1500 g for 5 min. Numerical Rating Score (NRS), Intermittent and Constant Osteoarthritis Pain (ICOAP) questionnaire, and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) function sub-score were used to measure pain and functional severity. Separate linear regression models were performed to determine whether baseline ultrasound-detected features of inflammation predicted the improvement in pain and function following PRP injection in both unadjusted and adjusted models for confounders.

RESULTS

Forty-four participants were included, with 25 (56.8%) being female. In an unadjusted model, higher OMERACT scores for inflammatory features such as global synovitis and/or effusion were significantly associated with greater improvement in all outcomes measured at 2 months but not at 6 and 12 months for pain measures. Only global synovitis showed significant association with functional improvement at 2 and 12 months. Similar findings were observed in the adjusted model.

CONCLUSION

Ultrasound indices of knee inflammation predicted short-term improvements in pain severity and both short- and longer-term improvements in function following intra-articular PRP injection.

Efficacy and safety of platelet-rich plasma injections for the treatment of osteoarthritis: a systematic review and meta-analysis of randomized controlled trials

Background

In recent years, platelet-rich plasma (PRP) injections for osteoarthritis (OA) have been widely promoted in clinical practice, but their effectiveness is controversial. Therefore, we conducted a meta-analysis of relevant randomized controlled trials (RCTs) to determine the efficacy and safety of PRP injections for the treatment of OA.

Methods

We searched databases including Embase, Web of Science, Medline, PubMed, and the Cochrane Library for relevant studies. Two researchers (YQX and CG) performed literature screening, baseline data extraction, literature quality assessment, and heterogeneity analysis of RCTs from the retrieved studies. Based on the magnitude of heterogeneity I², random-effects or fixed-effects models were selected for the meta-analysis.

Results

We included 24 RCTs comprising 1344 patients with OA who met the inclusion criteria, with the main types of morbidity being knee osteoarthritis (KOA), hip osteoarthritis (HOA), ankle osteoarthritis (AOA), and temporomandibular joint osteoarthritis (TMJOA). Our results indicate that PRP injections were effective in improving Visual Analog Scale (VAS) pain scores in patients with KOA, HOA, and AOA compared to controls (AOA, MD = -1.15, CI = 95% [-1.74, -0.56], I² = 40%, P < 0.05; KOA, MD = -1.03, CI = 95% [-1.16, -0.9], I² = 87%, P < 0.05; TMJOA, MD = -1.35, CI = 95% [-1.74, -0.97], I² = 92%, P < 0.05) but showed no significant efficacy in patients with HOA (MD = -0.27, CI = 95% [-0.8, 0.26], I² = 56%, P>0.05). Compared to controls, PRP injections were effective in improving Knee Injury and Osteoarthritis Outcome Score (KOOS), including the patient's pain symptoms, activities of daily living (ADL), and adhesion symptomatology, but not for that of sports function (KOOS-pain, MD = 2.77, CI = 95% [0, 5.53], I² = 0%, P < 0.05; KOOS-symptoms, MD = 3.73, CI = 95% [0.76, 6.71], I² = 0%, P < 0.05; KOOS-ADL, MD = 3.61, CI = 95% [0.79, 6.43], I² = 0%, P < 0.05; KOOS-QOL, MD = 4.66, CI = 95% [0.98, 8.35], I² = 29%, P < 0.05, KOOS-sport, MD = 0.48, CI = 95% [-3.02, 3.98], I² = 0%, P > 0.05). PRP injections were effective in improving Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores, including pain, stiffness, and functional joint motion, in patients with OA compared with the control group (WOMAC-pain, MD = -1.08, CI = 95% [-1.62, -0.53], I² = 87%, P < 0.05; WOMAC-stiffness, MD = -1.17, CI = 88% [-1.72, -0.63], I² = 87%, P < 0.05; WOMAC-function, MD = -1.12, CI = 95% [-1.65, -0.58], I² = 87%, P < 0.05). In addition, subgroup analysis showed that leukocyte-poor (LP) PRP injections were more effective than leukocyte-rich (LR) PRP injections in improving pain symptoms in patients with OA (VAS, LR-PRP, MD = -0.81, CI = 95% [-1.65, -0.03], I² = 83%, P = 0.06 > 0.05; LP-PRP, MD = -1.62, CI = 95% [-2.36, -0.88], I² = 92%, P < 0.05). A subgroup analysis based on injection sites showed that no statistical difference in efficacy between intra-articular (IA) combined with intra-osseous (IO) simultaneous PRP injections. IA PRP injections only improved VAS pain scores in patients with OA (IA+IO PRP injections, MD = -0.74, CI =95% [-1.29, -0.18], I² = 61%, P < 0.05; IA PRP injections, MD = -1.43, CI = 95% [-2.18, -0.68], I² = 87%, P < 0.05, test for subgroup differences, P > 0.05, I² = 52.7%).

Conclusion

PRP injection therapy can safely and effectively improve functional activity in patients with OA and produce positive analgesic effects in patients with KOA, TMJOA, and AOA. However, PRP injection therapy did not significantly reduce pain symptoms in patients with HOA. In addition, the analgesic effect of LP-PRP was greater than that of LR-PRP.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42022362066.

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.

Comparative Efficacy of Intra-Articular Injection, Physical Therapy, and Combined Treatments on Pain, Function, and Sarcopenia Indices in Knee Osteoarthritis: A Network Meta-Analysis of Randomized Controlled Trials

Knee osteoarthritis (KOA) is associated with a high risk of sarcopenia. Both intra-articular injections (IAIs) and physical therapy (PT) exert benefits in KOA. This network meta-analysis (NMA) study aimed to identify comparative efficacy among the combined treatments (IAI+PT) in patients with KOA. Seven electronic databases were systematically searched from inception until January 2023 for randomized controlled trials (RCTs) reporting the effects of IAI+PT vs. IAI or PT alone in patients with KOA. All RCTs which had treatment arms of IAI agents (autologous conditioned serum, botulinum neurotoxin type A, corticosteroids, dextrose prolotherapy (DxTP), hyaluronic acid, mesenchymal stem cells (MSC), ozone, platelet-rich plasma, plasma rich in growth factor, and stromal vascular fraction of adipose tissue) in combination with PT (exercise therapy, physical agent modalities (electrotherapy, shockwave therapy, thermal therapy), and physical activity training) were included in this NMA. A control arm receiving placebo IAI or usual care, without any other IAI or PT, was used as the reference group. The selected RCTs were analyzed through a frequentist method of NMA. The main outcomes included pain, global function (GF), and walking capability (WC). Meta-regression analyses were performed to explore potential moderators of the treatment efficacy. We included 80 RCTs (6934 patients) for analyses. Among the ten identified IAI+PT regimens, DxTP plus PT was the most optimal treatment for pain reduction (standard mean difference (SMD) = -2.54) and global function restoration (SMD = 2.28), whereas MSC plus PT was the most effective for enhancing WC recovery (SMD = 2.54). More severe KOA was associated with greater changes in pain (β = -2.52) and WC (β = 2.16) scores. Combined IAI+PT treatments afford more benefits than do their corresponding monotherapies in patients with KOA; however, treatment efficacy is moderated by disease severity.

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.

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).

Biologic Therapies for the Treatment of Knee Osteoarthritis: An Updated Systematic Review

BACKGROUND

Use of "orthobiologics" continues to expand for patients who have knee osteoarthritis (OA). We sought to perform a systemic review of biologic therapies relative to comparative groups, including the following: (1) platelet-rich plasma (PRP); (2) bone marrow-derived mesenchymal stem cells (BMSCs); (3) adipose-derived mesenchymal stem cells (ADSCs); and (4) amniotic-derived mesenchymal stem cells (AMSCs). We assessed the following: (1) study methodologies; (2) cell preparations and formulations; (3) patient-reported outcome scores (PROMs); and (4) structural changes.

METHODS

PubMed, Cochrane Library, and Embase databases were queried (2013-2021) to conduct a systematic review of biologic therapies for knee OA, according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Eighty-two studies were included: PRP (51); BMSC (15); ADSC (11); and AMSC (5). Study evaluations were made using the Modified Coleman Methodology Score. PROMs included the Western Ontario and McMaster Universities Arthritis Index and the Visual Analog Scale. Structural change evaluations included ultrasounds, radiographs, or magnetic resonance imaging.

RESULTS

PRP comprised a majority of the studies (n = 51), most with "fair" to "good" Modified Coleman Methodology Score. Studies had variable cell preparations and formulations, with comparison study results leading to inconsistent PROMs, and structural changes. A limited number of studies were included for BMSC, ADSC, and AMSC, all with similar findings to PRP.

CONCLUSION

Available literature evaluating "orthobiologics" for knee OA remain nonsuperior to comparison cohorts. Higher level studies with larger sample sizes and improved methodologies are warranted to suggest differences. Despite a growth of "orthobiologics" in clinics, this updated systematic review highlights the uncertain efficacy for use in knee OA.

The role of Platelet-Rich Plasma (PRP) intraarticular injections in restoring articular cartilage of osteoarthritic knees. A systematic review and meta-analysis

Objective

To assess the effect of PRP on knee articular cartilage content (thickness/volume) and examine the correlation between cartilage changes and clinical outcomes in patients with knee OA.

Method

A systematic literature search was performed using the Cochrane methodology in four online databases. Studies were included if they reported on cartilage content with cross-sectional imaging pre- and post-injection. A random-effects model meta-analysis was performed. Correlation with clinical outcomes was evaluated.

Results

14 studies (n ​= ​1099 patients) from 1452 records met the inclusion criteria: seven RCTs (n ​= ​688), one prospective (n ​= ​50), one retrospective (n ​= ​68), and four case-series (n ​= ​224). The PRP preparation process and treatment protocol varied widely (follow-up 6-12 months). In meta-analysis, PRP treatment was not associated with a significant increase in cartilage thickness (4 studies, n ​= ​187, standardized mean difference: Hedges g: 0.079; 95%CI: 0.358 - 0.516; p ​= ​0.723). Meta-analysis of 3 RCTs (n ​= ​112) showed no significant difference in the change of overall knee cartilage content with PRP injections compared with no PRP (Hedges' g: 0.217; 95%CI: 0.177 - 0.611; P ​= ​0.281).

Conclusion

The current literature does not support the PRP as chondrogenic in treatment of knee OA. However, there is substantial heterogeneity in the evaluated studies which limits the robustness of any conclusion. An adequately powered RCT, with a standardized PRP regime and standardized high-resolution MRI is needed to definitely define any effect of PRP on knee cartilage content and its relation to clinical outcomes. Until such high-quality evidence becomes available, we recommend that PRP is not administered with the intention of promoting chondrogenesis.

The Efficacy of Platelet-Rich Plasma for the Treatment of Knee Osteoarthritis Symptoms and Structural Changes: A Systematic Review and Meta-Analysis

BACKGROUND

Platelet-rich plasma (PRP) usage in orthopedics continues to rise, despite guidelines suggesting non-superiority to comparative cohorts. Therefore, we performed a systematic review and meta-analysis on PRP efficacy using two clinical assessments: (1) Visual Analog Scale and (2) Western Ontario and McMaster Universities Osteoarthritis Index. We assessed consistency and clinical relevancy by determining study heterogeneity (eg, sample sizes, ages, body mass index, arthritic severities, etc.). Comparative cohorts were: (A) hyaluronic acid (HA); (B) corticosteroid (CS); (C) normal saline (NS); and (D) exercise therapy. We performed sub-analyses of structural changes assessed on ultrasound, radiograph, or magnetic resonance imaging .

METHODS

We utilized PubMed, Cochrane Library, and Embase databases up to December 1, 2021, according to Preferred Reporting Items for Systematic-Reviews and Meta-Analyses guidelines. Twenty-four studies met criteria, with comparisons to: HA (n = 11); CS (n = 6); NS (n = 5); and exercise therapy (n = 3). Seven studies assessed structural changes. Evaluations utilized a methodological scoring system. I² statistics and forest plots pooled analyses and delineated study results.

RESULTS

PRP led to Visual Analog Scale and Western Ontario and McMaster Universities Osteoarthritis Index improvements in most studies when compared to HA, CS, and NS (P ≤ .05). Comparison to exercise therapy resulted in inconclusive findings (P ≥ .05). However, substantial heterogeneity (I² ≥ 76%) was reported due to study variability. No differences were found when assessing structural changes or cartilage thickness by magnetic resonance imaging (standardized mean difference -0.01 [-0.19, 0.18], P = .91).

CONCLUSIONS

PRP may be associated with pain and functional improvements but was not clinically relevant (inconsistent study- and patient-metrics). In addition, PRP did not confer superiority when assessing knee-related structural changes.

Osteotomies and Total Knee Arthroplasty: Systematic Review and Meta-Analysis

Total knee replacement (TKA) is a frequent modality performed in patients with osteoarthritis. Specific circumstances can make it much more difficult to execute successfully, and additional procedures such as osteotomy may be required. The aim of this study was to perform a meta-analysis and systematic review of osteotomies combined with TKA.

METHODS

In June 2022, a search PubMed, Embase, Cochrane, and Clinicaltrials was undertaken, adhering to PRISMA guidelines. The search included the terms "osteotomy" and "total knee arthroplasty".

RESULTS

Two subgroups (tibial tubercle osteotomy and medial femoral condyle osteotomy) were included in the meta-analysis. Further subgroups were described as a narrative review. The primary outcome showed no significant difference in favor to TTO. Secondary outcomes showed improved results in all presented subgroups compared to preoperative status.

CONCLUSION

This study showed a significant deficit of randomized control trials treated with osteotomies, in addition to TKA, and a lack of evidence-based surgical guidelines for the treatment of patients with OA in special conditions: posttraumatic deformities, stiff knee, severe varus, and valgus axis or patella disorders.

Comparison of the effects of autologous and allogeneic purified platelet-rich plasma on cartilage damage in a rabbit model of knee osteoarthritis

Background

Purified platelet-rich plasma (P-PRP) is gradually being used in the treatment of osteoarthritis (OA), and its sources are mainly divided into autologous and allogeneic blood. However, it is unclear whether autologous PRP is more effective or allogeneic PRP is superior.

Objective

In this study, autologous and allogeneic P-PRP was injected at early stage of KOA in rabbits, and then the differences in the efficacy of the two P-PRPs against KOA were compared from several perspectives, including pathological histology and immunohistochemistry.

Method

Experimental rabbits were divided into normal group (n = 8), model group (n = 8), autologous P-PRP group (n = 8), and allogeneic P-PRP group (n = 8) using a random number table method. The normal and model groups did not receive any treatment, and the autologous P-PRP and allogeneic P-PRP groups received intra-articular injections of autologous and allogeneic P-PRP, respectively, to observe the changes in the gross specimens of the knee joints of the experimental rabbits in each group. The histopathological changes of chondrocytes were also observed by HE-stained sections of articular cartilage, and the expression of chondrocytes Bone morphogenetic protein-2 (BMP-2) and Sox9 were detected by immunohistochemistry.

Results

Compared with the allogeneic P-PRP group, the differences were statistically significant (P < 0.05) in the gross specimens and pathological histological findings in the autologous PRP group. Immunohistochemical results showed that the expression of BMP-2 and Sox9 was elevated in both the autologous P-PRP group and the allogeneic P-PRP group compared with the model group, and the expression of BMP-2 was higher in the autologous P-PRP group than in the allogeneic P-PRP group, with a statistically significant difference (P < 0.05), while there was no difference in the expression of Sox9 between the two groups (P > 0.05).

Conclusion

Intra-articular injection of autologous P-PRP activated the expression of BMP-2 and Sox9 in chondrocytes and effectively improved KOA cartilage repair and reduced bone redundancy and joint fluid formation, and its efficacy was superior to that of intra-articular injection of allogeneic P-PRP.

Role of Platelets in Osteoarthritis-Updated Systematic Review and Meta-Analysis on the Role of Platelet-Rich Plasma in Osteoarthritis

Platelets are an essential component of hemostasis, with an increasing role in host inflammatory processes in injured tissues. The reaction between receptors and vascular endothelial cells results in the recruitment of platelets in the immune response pathway. The aim of the present review is to describe the role of platelets in osteoarthritis. Platelets induce secretion of biological substances, many of which are key players in the inflammatory response in osteoarthritis. Molecules involved in cartilage degeneration, or being markers of inflammation in osteoarthritis, are cytokines, such as tumor necrosis factor α (TNFα), interleukins (IL), type II collagen, aggrecan, and metalloproteinases. Surprisingly, platelets may also be used as a treatment modality for osteoarthritis. Multiple randomized controlled trials included in our systematic review and meta-analyses prove the effectiveness of platelet-rich plasma (PRP) as a minimally invasive method of pain alleviation in osteoarthritis treatment.

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.

PRP Injections for the Treatment of Knee Osteoarthritis: A Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

To evaluate effectiveness, in terms of patient-reported outcome measures, of platelet-rich plasma (PRP) injections for knee osteoarthritis compared to placebo and other intraarticular treatments.

DESIGN

PubMed, Cochrane Library, Scopus, Embase, Web of Science, as well as the gray literature were searched on January 17, 2020. Randomized controlled trials (RCTs) comparing PRP injections with placebo or other injectable treatments, in any language, on humans, were included. Risk of bias was assessed following the Cochrane guidelines; quality of evidence was graded using the GRADE guidelines.

RESULTS

Thirty-four RCTs, including 1403 knees in PRP groups and 1426 in control groups, were selected. WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) score favored PRP, with a statistically and clinically significant difference versus placebo at 12-month follow-up (P = 0.02) and versus HA (hyaluronic acid) at 6-month (P < 0.001) and 12-month (P < 0.001) follow-ups. A clinically significant difference favoring PRP versus steroids was documented for VAS (Visual Analogue Scale) pain (P < 0.001), KOOS (Knee Injury and Osteoarthritis Outcome Score) pain (P < 0.001), function in daily activities (P = 0.001), and quality of life (P < 0.001) at 6-month follow-up. However, superiority of PRP did not reach the minimal clinically important difference for all outcomes, and quality of evidence was low.

CONCLUSIONS

The effect of platelet concentrates goes beyond its mere placebo effect, and PRP injections provide better results than other injectable options. This benefit increases over time, being not significant at earlier follow-ups but becoming clinically significant after 6 to 12 months. However, although substantial, the improvement remains partial and supported by low level of evidence. This finding urges further research to confirm benefits and identify the best formulation and indications for PRP injections in knee OA.

Injectable therapies for knee osteoarthritis

Knee osteoarthritis is a degenerative arthritis that mainly affects older adults. Over time, osteoarthritis can result in significant and sustained discomfort, pain, and disability. Current treatment focuses on the alleviation of pain and functional impairment. While arthroplasty is the definitive management option, it subjects patients to surgical complications, and the possibility of surgical revisions. In addition, many patients are not surgical candidates. Instead, pharmacological therapy is recommended first-line for most patients. On top of pharmacological therapy, there are a range of non-operative procedural options available. However, leading professional guidelines vary in their recommendations for these agents. Therefore, we present a review of recent randomized controlled trials and meta-analyses on injectable corticosteroids, hyaluronic acid (HA), platelet-rich plasma (PRP), mesenchymal stem cell injections, and ozone therapy. The preliminary data reveal the strongest evidence in favour of corticosteroid injections, although there are promising findings regarding the long-term efficacy of HA and PRP.

Effect of Intra-articular Platelet-Rich Plasma vs Placebo Injection on Pain and Medial Tibial Cartilage Volume in Patients With Knee Osteoarthritis: The RESTORE Randomized Clinical Trial

IMPORTANCE

Most clinical guidelines do not recommend platelet-rich plasma (PRP) for knee osteoarthritis (OA) because of lack of high-quality evidence on efficacy for symptoms and joint structure, but the guidelines emphasize the need for rigorous studies. Despite this, use of PRP in knee OA is increasing.

OBJECTIVE

To evaluate the effects of intra-articular PRP injections on symptoms and joint structure in patients with symptomatic mild to moderate radiographic medial knee OA.

DESIGN, SETTING, AND PARTICIPANTS

This randomized, 2-group, placebo-controlled, participant-, injector-, and assessor-blinded clinical trial enrolled community-based participants (n = 288) aged 50 years or older with symptomatic medial knee OA (Kellgren and Lawrence grade 2 or 3) in Sydney and Melbourne, Australia, from August 24, 2017, to July 5, 2019. The 12-month follow-up was completed on July 22, 2020.

INTERVENTIONS

Interventions involved 3 intra-articular injections at weekly intervals of either leukocyte-poor PRP using a commercially available product (n = 144 participants) or saline placebo (n = 144 participants).

MAIN OUTCOMES AND MEASURES

The 2 primary outcomes were 12-month change in overall average knee pain scores (11-point scale; range, 0-10, with higher scores indicating worse pain; minimum clinically important difference of 1.8) and percentage change in medial tibial cartilage volume as assessed by magnetic resonance imaging (MRI). Thirty-one secondary outcomes (25 symptom related and 6 MRI assessed; minimum clinically important difference not known) evaluated pain, function, quality of life, global change, and joint structures at 2-month and/or 12-month follow-up.

RESULTS

Among 288 patients who were randomized (mean age, 61.9 [SD, 6.5] years; 169 [59%] women), 269 (93%) completed the trial. In both groups, 140 participants (97%) received all 3 injections. After 12 months, treatment with PRP vs placebo injection resulted in a mean change in knee pain scores of -2.1 vs -1.8 points, respectively (difference, -0.4 [95% CI, -0.9 to 0.2] points; P = .17). The mean change in medial tibial cartilage volume was -1.4% vs -1.2%, respectively (difference, -0.2% [95% CI, -1.9% to 1.5%]; P = .81). Of 31 prespecified secondary outcomes, 29 showed no significant between-group differences.

CONCLUSIONS AND RELEVANCE

Among patients with symptomatic mild to moderate radiographic knee OA, intra-articular injection of PRP, compared with injection of saline placebo, did not result in a significant difference in symptoms or joint structure at 12 months. These findings do not support use of PRP for the management of knee OA.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry Identifier: ACTRN12617000853347.

Efficacy of platelet-rich plasma and plasma for symptomatic treatment of knee osteoarthritis: a double-blinded placebo-controlled randomized clinical trial

Background

Platelet-rich plasma (PRP) has a still conflicting efficacy for knee osteoarthritis (KOA) and might be a minimally invasive and safe treatment alternative. The potential benefit of only plasma (non-enriched) has never been investigated. Our aim was to evaluate the efficacy of intra-articular platelet-rich plasma (PRP) and plasma to improve pain and function in participants with KOA over 24 weeks.

Methods

Randomized, double-blind, placebo-controlled trial with 3 groups (n = 62): PRP (n = 20), plasma (n = 21) and saline (n = 21). Two ultrasound-guided knee injections were performed with a 2-week interval. The primary outcome was visual analog scale 0-10 cm (VAS) for overall pain at week 24, with intermediate assessments at weeks 6 and 12. Main secondary outcomes were: KOOS, OMERACT-OARSI criteria and TUGT.

Results

At baseline, 92% of participants were female, with a mean age of 65 years, mean BMI of 28.0 Kg/m²and mean VAS pain of 6.2 cm. Change in pain from baseline at week 24 were -2.9 (SD 2.5), -2.4 (SD 2.5) and -3.5 cm (SD 3.3) for PRP, plasma and saline, respectively (p intergroup = 0.499). There were no differences between the three groups at weeks 6 and 12. Similarly, there were no differences between groups regarding secondary outcomes. The PRP group showed higher frequency of adverse events (65% versus 24% and 33% for plasma and saline, respectively, p = 0.02), mostly mild transitory increase in pain.

Conclusions

PRP and plasma were not superior to placebo for pain and function improvement in KOA over 24 weeks. The PRP group had a higher frequency of mild transitory increase in pain.

Trial registration

ClinicalTrials.gov, NCT03138317, 03/05/2017.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04706-7.

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.

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.

Role of platelet-rich plasma in the treatment of osteoarthritis: a meta-analysis

OBJECTIVE

The clinical efficacy of platelet-rich plasma (PRP) in the treatment of osteoarthritis remains controversial. In this paper, we evaluated the clinical efficacy of PRP in the treatment of osteoarthritis using meta-analysis, providing evidence for the selection of clinical treatment options.

METHODS

We performed a computer-based search of PubMed, Embase, and the Cochrane Library databases to retrieve articles using the search terms "platelet-rich plasma", "osteoarthrosis", and "knee joint". Quality evaluation and data extraction were performed. The combined effect was assessed using RevMan 5.3 software.

RESULTS

Five randomized controlled trials, involving 320 patients, were included in this study. No significant differences were observed in the International Knee Documentation Committee score, visual analog scale (VAS) score, or the absolute value of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score between the experimental and control groups. The absolute value of the VAS score and change in the WOMAC score were significantly decreased and patient satisfaction was increased in the experimental group, as compared with the control group.

CONCLUSION

The findings of this meta-analysis suggest that intra-articular injection of PRP is an effective treatment for osteoarthritis that can reduce post-operative pain, improve locomotor function, and increase patient satisfaction.

Efficacy and Safety of Intra-Articular Platelet-Rich Plasma in Osteoarthritis Knee: A Systematic Review and Meta-Analysis

Background

Knee osteoarthritis (KOA) is a common disease in aged adults. Intra-articular (IA) injection of platelet-rich plasma (PRP) therapy is an effective minimally invasive treatment for KOA. We aimed to compare the efficacy and safety of platelet-rich plasma (PRP) with placebo or other conservative treatments.

Methods

We conducted a meta-analysis to identify relevant articles from online register databases such as PubMed, Medline, Embase, and the Cochrane Library. The primary outcomes were the visual analogue scale (VAS) score, Western Ontario and McMaster Universities Arthritis Index (WOMAC) score, and International Knee Documentation Committee (IKDC) subjective score. The secondary outcome was the adverse event rate.

Results

A total of 895 articles were identified, of which 23 randomized controlled trials that met the inclusion criteria were determined as eligible. Compared with placebo, PRP had a lower VAS score and higher IKDC subjective score at the 6^th month after treatment and significantly less WOMAC score during the follow-up period. Compared with oral NSAIDs, PRP gained a lower WOMAC score at the 6^th month after treatment. The VAS score decreased after treatment when reaching PRP and CS. As compared to the HA, the VAS score, WOMAC score, and IKDC subjective score all revealed better PRP results. There were no significant differences in adverse event rates comparing PRP versus placebo or HA. Different PRP applications did not show significant differences in VAS score in the 1^st month and WOMAC score in the 3^rd month after treatment.

Conclusion

To compare with the conservative treatments mentioned above, PRP is more effective in relieving symptoms. There were no significant differences between triple PRP application and single PRP application in short-term curative effect.

Association of Gut Microbiome and Vitamin D Deficiency in Knee Osteoarthritis Patients: A Pilot Study

BACKGROUND

Few preclinical studies have shown that Knee osteoarthritis (KOA) is linked to gut microbiome dysbiosis and chronic inflammation. This pilot study was designed to look at the gut microbiome composition in KOA patients and normal individuals with or without vitamin D deficiency (VDD, serum vitamin D <30 ng/mL).

METHODS

This pilot study was conducted prospectively in 24 participants. The faecal samples of all the participants were taken for DNA extraction. The V3-V4 region of 16s rRNA was amplified, and the library was prepared and sequenced on the Illumina Miseq platform.

RESULTS

The mean (±SD) age was 45.5 (±10.2) years with no defined comorbidities. Of 447 total Operational Taxonomic Units (OTUs), a differential abundance of 16 nominally significant OTUs between the groups was observed. Linear discriminate analysis (LEfSe) revealed a significant difference in bacteria among the study groups. Pseudobutyrivibrio and Odoribacter were specific for VDD, while Parabacteroides, Butyricimonas and Gordonibacter were abundant in the KOA_VDD group, and Peptococcus, Intestimonas, Delftia and Oribacterium were abundant in the KOA group. About 80% of bacterial species were common among different groups and hence labelled as core bacterial species. However, the core microbiome of KOA and VDD groups were not seen in the KOA_VDD group, suggesting that these bacterial groups were affected by the interaction of the KOA and VDD factors.

CONCLUSION

Parabacteroides, Butyricimonas, Pseudobutyrivibrio, Odoribacter and Gordonibacter are the predominant bacteria in vitamin D deficient patients with or without KOA. Together these results indicate an association between the gut microbiome, vitamin D and knee osteoarthritis.

Nonsurgical Management of Cartilage Defects of the Knee: Who, When, Why, and How?

The nonoperative practitioner managing individuals with cartilage defects should use a patient-centered, multifaceted approach that aims to individualize treatment to provide optimal benefit. These include addressing modifiable risk factors for disease progression and instituting interventions such as weight loss, nutrition, physical activity, and potentially regenerative medicine strategies. This review will focus on these nonoperative treatment strategies with a focus on when treatments are necessary, who will benefit from these approaches, why they are specifically appropriate, and, finally, how these treatments directly modify the structure of a patient's cartilage and resulting symptoms.

The Clinical Use of Platelet-Rich Plasma in Knee Disorders and Surgery-A Systematic Review and Meta-Analysis

In recent years, the interest in biological treatment of knee lesions has increased, especially the application of platelet-rich plasma is of particular note. The number of articles evaluating platelet-rich plasma (PRP) efficacy in the recovery of knee disorders and during knee surgery has exponentially increased over the last decade. A systematic review with meta-analyses was performed by assessing selected studies of local PRP injections to the knee joint. The study was completed in accordance with 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. A multistep search of PubMed, Embase, Cochrane Database of Systematic Reviews, and Clinicaltrials.gov was performed to identify studies on knee surgery and knee lesion treatment with PRP. Of the 4004 articles initially identified, 357 articles focusing on knee lesions were selected and, consequently, only 83 clinical trials were analyzed using the revised Cochrane risk-of-bias tool to evaluate risk. In total, seven areas of meta-analysis reported a positive effect of PRP. Among them, 10 sub-analyses demonstrated significant differences in favor of PRP when compared to the control groups (p < 0.05). This study showed the positive effects of PRP, both on the recovery of knee disorders and during knee surgery; however further prospective and randomized studies with a higher number of subjects and with lower biases are needed.

Platelet Concentrates in Musculoskeletal Medicine

Platelet concentrates (PCs), mostly represented by platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) are autologous biological blood-derived products that may combine plasma/platelet-derived bioactive components, together with fibrin-forming protein able to create a natural three-dimensional scaffold. These types of products are safely used in clinical applications due to the autologous-derived source and the minimally invasive application procedure. In this narrative review, we focus on three main topics concerning the use of platelet concentrate for treating musculoskeletal conditions: (a) the different procedures to prepare PCs, (b) the composition of PCs that is related to the type of methodological procedure adopted and (c) the clinical application in musculoskeletal medicine, efficacy and main limits of the different studies.

Platelet-Rich Plasma for Sport-Active Patients with Knee Osteoarthritis: Limited Return to Sport

Objective

To evaluate a cohort of sport-active patients suffering from cartilage degeneration and OA, in terms of clinical outcome and return to sport (RTS) after platelet-rich plasma (PRP) injective treatment.

Design

This study included forty-seven sport-active patients ≤50 years old with unilateral symptomatic knee cartilage degeneration or OA. Patients received 3 PRP injections and were prospectively evaluated at baseline and then at 2, 6, 12, and 24 months follow-up by IKDC subjective EQ-VAS, and Tegner scores. Furthermore, patients were asked about their RTS, in terms of return to any sport level or to their activity level before symptoms onset.

Results

IKDC subjective score improved significantly at all follow-ups, changing from 59.2 ± 13.6 to 70.6 ± 13 at 12 months and to 76.7 ± 12.5 at 24 months (p < 0.0005). A similar outcome was observed with the EQ-VAS score. Tegner score improved from 3.6 ± 1.4 to 4.8 ± 0.9 at 24 months (p < 0.0005). A similar outcome was observed with the EQ-VAS score. Tegner score improved from 3.6 ± 1.4 to 4.8 ± 0.9 at 24 months (p < 0.0005). A similar outcome was observed with the EQ-VAS score. Tegner score improved from 3.6 ± 1.4 to 4.8 ± 0.9 at 24 months (p < 0.0005). A similar outcome was observed with the EQ-VAS score. Tegner score improved from 3.6 ± 1.4 to 4.8 ± 0.9 at 24 months (

Conclusions

Sport-active patients affected by knee OA can benefit from PRP injections, with pain and function improvement over time. However, results are less satisfactory in terms of RTS since only half can achieve the same sport level as before the onset of symptoms. Patients undergoing PRP treatment should be made aware of their low chances to go back to high-impact sport activities.

[Prospective clinical study on extracorporeal shock wave therapy combined with platelet-rich plasma injection for knee osteoarthritis]

OBJECTIVE

To investigate the effectiveness of extracorporeal shock wave therapy combined with platelet-rich plasma (PRP) injection in treatment of knee osteoarthritis (KOA) by prospective clinical study.

METHODS

Between June 2015 and June 2018, 180 patients with KOA met the inclusion criteria were included in study and randomly allocated to group A (n=60), group B (n=60), and group C (n=60). The patients were treated with autologous PRP intra-articular injection in group A, extracorporeal shock wave therapy in group B, and extracorporeal shock wave therapy combined with autologous PRP intra-articular injection in group C, once a week and 5 times a duration of treatment. There was no significant difference in age, gender, disease duration, side of KOA, and Kellgren-Lawrence grading between groups (P>0.05). The pain and function of knee joint were assessed by visual analogue scale (VAS) score, Lequesne Index score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and knee joint activity before treatment and at 1, 3, and 5 weeks after the first treatment.

RESULTS

There were significant differences in VAS score, Lequesne Index score, WOMAC score, and knee joint activity between pre- and post-treatment in all groups (P<0.05). VAS score, Lequesne Index score, and WOMAC score gradually decreased with the prolongation of treatment time (P<0.05); but there was no significant difference in knee joint activity between different time points (P>0.05). There was no significant difference in VAS score, Lequesne Index score, WOMAC score, and knee joint activity between groups before treatment (P>0.05); the scores of group C were superior to groups A and B (P< 0.05) at different time points after treatment; while the knee joint activities of 3 groups were similar (P>0.05).

CONCLUSION

The extracorporeal shock wave therapy combined with PRP injection can relieve the pain synergistically for KOA.